aboutsummaryrefslogblamecommitdiffstats
path: root/include/asm-cris/scatterlist.h
blob: 4bdc44c4ac3d74a1477dc8654dc1f3f78b3ea5a1 (plain) (tree) 
1da177e4c3f4




















1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20




















                                                                       
#ifndef __ASM_CRIS_SCATTERLIST_H
#define __ASM_CRIS_SCATTERLIST_H

struct scatterlist {
	char *  address;    /* Location data is to be transferred to */
	unsigned int length;

	/* The following is i386 highmem junk - not used by us */
	struct page * page; /* Location for highmem page, if any */
	unsigned int offset;/* for highmem, page offset */

};

#define sg_dma_address(sg)	((sg)->address)
#define sg_dma_len(sg)		((sg)->length)
/* i386 junk */

#define ISA_DMA_THRESHOLD (0x1fffffff)

#endif /* !(__ASM_CRIS_SCATTERLIST_H) */
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-13 07:12:43 -0500
263'>263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 
/*
   drbd.c

   This file is part of DRBD by Philipp Reisner and Lars Ellenberg.

   Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
   Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
   Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.

   Thanks to Carter Burden, Bart Grantham and Gennadiy Nerubayev
   from Logicworks, Inc. for making SDP replication support possible.

   drbd is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   drbd is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with drbd; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/drbd.h>
#include <linux/uaccess.h>
#include <asm/types.h>
#include <net/sock.h>
#include <linux/ctype.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/memcontrol.h>
#include <linux/mm_inline.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/reboot.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/workqueue.h>
#define __KERNEL_SYSCALLS__
#include <linux/unistd.h>
#include <linux/vmalloc.h>

#include <linux/drbd_limits.h>
#include "drbd_int.h"
#include "drbd_protocol.h"
#include "drbd_req.h" /* only for _req_mod in tl_release and tl_clear */
#include "drbd_vli.h"
#include "drbd_debugfs.h"

static DEFINE_MUTEX(drbd_main_mutex);
static int drbd_open(struct block_device *bdev, fmode_t mode);
static void drbd_release(struct gendisk *gd, fmode_t mode);
static void md_sync_timer_fn(unsigned long data);
static int w_bitmap_io(struct drbd_work *w, int unused);

MODULE_AUTHOR("Philipp Reisner <phil@linbit.com>, "
	      "Lars Ellenberg <lars@linbit.com>");
MODULE_DESCRIPTION("drbd - Distributed Replicated Block Device v" REL_VERSION);
MODULE_VERSION(REL_VERSION);
MODULE_LICENSE("GPL");
MODULE_PARM_DESC(minor_count, "Approximate number of drbd devices ("
		 __stringify(DRBD_MINOR_COUNT_MIN) "-" __stringify(DRBD_MINOR_COUNT_MAX) ")");
MODULE_ALIAS_BLOCKDEV_MAJOR(DRBD_MAJOR);

#include <linux/moduleparam.h>
/* allow_open_on_secondary */
MODULE_PARM_DESC(allow_oos, "DONT USE!");
/* thanks to these macros, if compiled into the kernel (not-module),
 * this becomes the boot parameter drbd.minor_count */
module_param(minor_count, uint, 0444);
module_param(disable_sendpage, bool, 0644);
module_param(allow_oos, bool, 0);
module_param(proc_details, int, 0644);

#ifdef CONFIG_DRBD_FAULT_INJECTION
int enable_faults;
int fault_rate;
static int fault_count;
int fault_devs;
/* bitmap of enabled faults */
module_param(enable_faults, int, 0664);
/* fault rate % value - applies to all enabled faults */
module_param(fault_rate, int, 0664);
/* count of faults inserted */
module_param(fault_count, int, 0664);
/* bitmap of devices to insert faults on */
module_param(fault_devs, int, 0644);
#endif

/* module parameter, defined */
unsigned int minor_count = DRBD_MINOR_COUNT_DEF;
bool disable_sendpage;
bool allow_oos;
int proc_details;       /* Detail level in proc drbd*/

/* Module parameter for setting the user mode helper program
 * to run. Default is /sbin/drbdadm */
char usermode_helper[80] = "/sbin/drbdadm";

module_param_string(usermode_helper, usermode_helper, sizeof(usermode_helper), 0644);

/* in 2.6.x, our device mapping and config info contains our virtual gendisks
 * as member "struct gendisk *vdisk;"
 */
struct idr drbd_devices;
struct list_head drbd_resources;
struct mutex resources_mutex;

struct kmem_cache *drbd_request_cache;
struct kmem_cache *drbd_ee_cache;	/* peer requests */
struct kmem_cache *drbd_bm_ext_cache;	/* bitmap extents */
struct kmem_cache *drbd_al_ext_cache;	/* activity log extents */
mempool_t *drbd_request_mempool;
mempool_t *drbd_ee_mempool;
mempool_t *drbd_md_io_page_pool;
struct bio_set *drbd_md_io_bio_set;

/* I do not use a standard mempool, because:
   1) I want to hand out the pre-allocated objects first.
   2) I want to be able to interrupt sleeping allocation with a signal.
   Note: This is a single linked list, the next pointer is the private
	 member of struct page.
 */
struct page *drbd_pp_pool;
spinlock_t   drbd_pp_lock;
int          drbd_pp_vacant;
wait_queue_head_t drbd_pp_wait;

DEFINE_RATELIMIT_STATE(drbd_ratelimit_state, 5 * HZ, 5);

static const struct block_device_operations drbd_ops = {
	.owner =   THIS_MODULE,
	.open =    drbd_open,
	.release = drbd_release,
};

struct bio *bio_alloc_drbd(gfp_t gfp_mask)
{
	struct bio *bio;

	if (!drbd_md_io_bio_set)
		return bio_alloc(gfp_mask, 1);

	bio = bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
	if (!bio)
		return NULL;
	return bio;
}

#ifdef __CHECKER__
/* When checking with sparse, and this is an inline function, sparse will
   give tons of false positives. When this is a real functions sparse works.
 */
int _get_ldev_if_state(struct drbd_device *device, enum drbd_disk_state mins)
{
	int io_allowed;

	atomic_inc(&device->local_cnt);
	io_allowed = (device->state.disk >= mins);
	if (!io_allowed) {
		if (atomic_dec_and_test(&device->local_cnt))
			wake_up(&device->misc_wait);
	}
	return io_allowed;
}

#endif

/**
 * tl_release() - mark as BARRIER_ACKED all requests in the corresponding transfer log epoch
 * @connection:	DRBD connection.
 * @barrier_nr:	Expected identifier of the DRBD write barrier packet.
 * @set_size:	Expected number of requests before that barrier.
 *
 * In case the passed barrier_nr or set_size does not match the oldest
 * epoch of not yet barrier-acked requests, this function will cause a
 * termination of the connection.
 */
void tl_release(struct drbd_connection *connection, unsigned int barrier_nr,
		unsigned int set_size)
{
	struct drbd_request *r;
	struct drbd_request *req = NULL;
	int expect_epoch = 0;
	int expect_size = 0;

	spin_lock_irq(&connection->resource->req_lock);

	/* find oldest not yet barrier-acked write request,
	 * count writes in its epoch. */
	list_for_each_entry(r, &connection->transfer_log, tl_requests) {
		const unsigned s = r->rq_state;
		if (!req) {
			if (!(s & RQ_WRITE))
				continue;
			if (!(s & RQ_NET_MASK))
				continue;
			if (s & RQ_NET_DONE)
				continue;
			req = r;
			expect_epoch = req->epoch;
			expect_size ++;
		} else {
			if (r->epoch != expect_epoch)
				break;
			if (!(s & RQ_WRITE))
				continue;
			/* if (s & RQ_DONE): not expected */
			/* if (!(s & RQ_NET_MASK)): not expected */
			expect_size++;
		}
	}

	/* first some paranoia code */
	if (req == NULL) {
		drbd_err(connection, "BAD! BarrierAck #%u received, but no epoch in tl!?\n",
			 barrier_nr);
		goto bail;
	}
	if (expect_epoch != barrier_nr) {
		drbd_err(connection, "BAD! BarrierAck #%u received, expected #%u!\n",
			 barrier_nr, expect_epoch);
		goto bail;
	}

	if (expect_size != set_size) {
		drbd_err(connection, "BAD! BarrierAck #%u received with n_writes=%u, expected n_writes=%u!\n",
			 barrier_nr, set_size, expect_size);
		goto bail;
	}

	/* Clean up list of requests processed during current epoch. */
	/* this extra list walk restart is paranoia,
	 * to catch requests being barrier-acked "unexpectedly".
	 * It usually should find the same req again, or some READ preceding it. */
	list_for_each_entry(req, &connection->transfer_log, tl_requests)
		if (req->epoch == expect_epoch)
			break;
	list_for_each_entry_safe_from(req, r, &connection->transfer_log, tl_requests) {
		if (req->epoch != expect_epoch)
			break;
		_req_mod(req, BARRIER_ACKED);
	}
	spin_unlock_irq(&connection->resource->req_lock);

	return;

bail:
	spin_unlock_irq(&connection->resource->req_lock);
	conn_request_state(connection, NS(conn, C_PROTOCOL_ERROR), CS_HARD);
}


/**
 * _tl_restart() - Walks the transfer log, and applies an action to all requests
 * @connection:	DRBD connection to operate on.
 * @what:       The action/event to perform with all request objects
 *
 * @what might be one of CONNECTION_LOST_WHILE_PENDING, RESEND, FAIL_FROZEN_DISK_IO,
 * RESTART_FROZEN_DISK_IO.
 */
/* must hold resource->req_lock */
void _tl_restart(struct drbd_connection *connection, enum drbd_req_event what)
{
	struct drbd_request *req, *r;

	list_for_each_entry_safe(req, r, &connection->transfer_log, tl_requests)
		_req_mod(req, what);
}

void tl_restart(struct drbd_connection *connection, enum drbd_req_event what)
{
	spin_lock_irq(&connection->resource->req_lock);
	_tl_restart(connection, what);
	spin_unlock_irq(&connection->resource->req_lock);
}

/**
 * tl_clear() - Clears all requests and &struct drbd_tl_epoch objects out of the TL
 * @device:	DRBD device.
 *
 * This is called after the connection to the peer was lost. The storage covered
 * by the requests on the transfer gets marked as our of sync. Called from the
 * receiver thread and the worker thread.
 */
void tl_clear(struct drbd_connection *connection)
{
	tl_restart(connection, CONNECTION_LOST_WHILE_PENDING);
}

/**
 * tl_abort_disk_io() - Abort disk I/O for all requests for a certain device in the TL
 * @device:	DRBD device.
 */
void tl_abort_disk_io(struct drbd_device *device)
{
	struct drbd_connection *connection = first_peer_device(device)->connection;
	struct drbd_request *req, *r;

	spin_lock_irq(&connection->resource->req_lock);
	list_for_each_entry_safe(req, r, &connection->transfer_log, tl_requests) {
		if (!(req->rq_state & RQ_LOCAL_PENDING))
			continue;
		if (req->device != device)
			continue;
		_req_mod(req, ABORT_DISK_IO);
	}
	spin_unlock_irq(&connection->resource->req_lock);
}

static int drbd_thread_setup(void *arg)
{
	struct drbd_thread *thi = (struct drbd_thread *) arg;
	struct drbd_resource *resource = thi->resource;
	unsigned long flags;
	int retval;

	snprintf(current->comm, sizeof(current->comm), "drbd_%c_%s",
		 thi->name[0],
		 resource->name);

restart:
	retval = thi->function(thi);

	spin_lock_irqsave(&thi->t_lock, flags);

	/* if the receiver has been "EXITING", the last thing it did
	 * was set the conn state to "StandAlone",
	 * if now a re-connect request comes in, conn state goes C_UNCONNECTED,
	 * and receiver thread will be "started".
	 * drbd_thread_start needs to set "RESTARTING" in that case.
	 * t_state check and assignment needs to be within the same spinlock,
	 * so either thread_start sees EXITING, and can remap to RESTARTING,
	 * or thread_start see NONE, and can proceed as normal.
	 */

	if (thi->t_state == RESTARTING) {
		drbd_info(resource, "Restarting %s thread\n", thi->name);
		thi->t_state = RUNNING;
		spin_unlock_irqrestore(&thi->t_lock, flags);
		goto restart;
	}

	thi->task = NULL;
	thi->t_state = NONE;
	smp_mb();
	complete_all(&thi->stop);
	spin_unlock_irqrestore(&thi->t_lock, flags);

	drbd_info(resource, "Terminating %s\n", current->comm);

	/* Release mod reference taken when thread was started */

	if (thi->connection)
		kref_put(&thi->connection->kref, drbd_destroy_connection);
	kref_put(&resource->kref, drbd_destroy_resource);
	module_put(THIS_MODULE);
	return retval;
}

static void drbd_thread_init(struct drbd_resource *resource, struct drbd_thread *thi,
			     int (*func) (struct drbd_thread *), const char *name)
{
	spin_lock_init(&thi->t_lock);
	thi->task    = NULL;
	thi->t_state = NONE;
	thi->function = func;
	thi->resource = resource;
	thi->connection = NULL;
	thi->name = name;
}

int drbd_thread_start(struct drbd_thread *thi)
{
	struct drbd_resource *resource = thi->resource;
	struct task_struct *nt;
	unsigned long flags;

	/* is used from state engine doing drbd_thread_stop_nowait,
	 * while holding the req lock irqsave */
	spin_lock_irqsave(&thi->t_lock, flags);

	switch (thi->t_state) {
	case NONE:
		drbd_info(resource, "Starting %s thread (from %s [%d])\n",
			 thi->name, current->comm, current->pid);

		/* Get ref on module for thread - this is released when thread exits */
		if (!try_module_get(THIS_MODULE)) {
			drbd_err(resource, "Failed to get module reference in drbd_thread_start\n");
			spin_unlock_irqrestore(&thi->t_lock, flags);
			return false;
		}

		kref_get(&resource->kref);
		if (thi->connection)
			kref_get(&thi->connection->kref);

		init_completion(&thi->stop);
		thi->reset_cpu_mask = 1;
		thi->t_state = RUNNING;
		spin_unlock_irqrestore(&thi->t_lock, flags);
		flush_signals(current); /* otherw. may get -ERESTARTNOINTR */

		nt = kthread_create(drbd_thread_setup, (void *) thi,
				    "drbd_%c_%s", thi->name[0], thi->resource->name);

		if (IS_ERR(nt)) {
			drbd_err(resource, "Couldn't start thread\n");

			if (thi->connection)
				kref_put(&thi->connection->kref, drbd_destroy_connection);
			kref_put(&resource->kref, drbd_destroy_resource);
			module_put(THIS_MODULE);
			return false;
		}
		spin_lock_irqsave(&thi->t_lock, flags);
		thi->task = nt;
		thi->t_state = RUNNING;
		spin_unlock_irqrestore(&thi->t_lock, flags);
		wake_up_process(nt);
		break;
	case EXITING:
		thi->t_state = RESTARTING;
		drbd_info(resource, "Restarting %s thread (from %s [%d])\n",
				thi->name, current->comm, current->pid);
		/* fall through */
	case RUNNING:
	case RESTARTING:
	default:
		spin_unlock_irqrestore(&thi->t_lock, flags);
		break;
	}

	return true;
}


void _drbd_thread_stop(struct drbd_thread *thi, int restart, int wait)
{
	unsigned long flags;

	enum drbd_thread_state ns = restart ? RESTARTING : EXITING;

	/* may be called from state engine, holding the req lock irqsave */
	spin_lock_irqsave(&thi->t_lock, flags);

	if (thi->t_state == NONE) {
		spin_unlock_irqrestore(&thi->t_lock, flags);
		if (restart)
			drbd_thread_start(thi);
		return;
	}

	if (thi->t_state != ns) {
		if (thi->task == NULL) {
			spin_unlock_irqrestore(&thi->t_lock, flags);
			return;
		}

		thi->t_state = ns;
		smp_mb();
		init_completion(&thi->stop);
		if (thi->task != current)
			force_sig(DRBD_SIGKILL, thi->task);
	}

	spin_unlock_irqrestore(&thi->t_lock, flags);

	if (wait)
		wait_for_completion(&thi->stop);
}

int conn_lowest_minor(struct drbd_connection *connection)
{
	struct drbd_peer_device *peer_device;
	int vnr = 0, minor = -1;

	rcu_read_lock();
	peer_device = idr_get_next(&connection->peer_devices, &vnr);
	if (peer_device)
		minor = device_to_minor(peer_device->device);
	rcu_read_unlock();

	return minor;
}

#ifdef CONFIG_SMP
/**
 * drbd_calc_cpu_mask() - Generate CPU masks, spread over all CPUs
 *
 * Forces all threads of a resource onto the same CPU. This is beneficial for
 * DRBD's performance. May be overwritten by user's configuration.
 */
static void drbd_calc_cpu_mask(cpumask_var_t *cpu_mask)
{
	unsigned int *resources_per_cpu, min_index = ~0;

	resources_per_cpu = kzalloc(nr_cpu_ids * sizeof(*resources_per_cpu), GFP_KERNEL);
	if (resources_per_cpu) {
		struct drbd_resource *resource;
		unsigned int cpu, min = ~0;

		rcu_read_lock();
		for_each_resource_rcu(resource, &drbd_resources) {
			for_each_cpu(cpu, resource->cpu_mask)
				resources_per_cpu[cpu]++;
		}
		rcu_read_unlock();
		for_each_online_cpu(cpu) {
			if (resources_per_cpu[cpu] < min) {
				min = resources_per_cpu[cpu];
				min_index = cpu;
			}
		}
		kfree(resources_per_cpu);
	}
	if (min_index == ~0) {
		cpumask_setall(*cpu_mask);
		return;
	}
	cpumask_set_cpu(min_index, *cpu_mask);
}

/**
 * drbd_thread_current_set_cpu() - modifies the cpu mask of the _current_ thread
 * @device:	DRBD device.
 * @thi:	drbd_thread object
 *
 * call in the "main loop" of _all_ threads, no need for any mutex, current won't die
 * prematurely.
 */
void drbd_thread_current_set_cpu(struct drbd_thread *thi)
{
	struct drbd_resource *resource = thi->resource;
	struct task_struct *p = current;

	if (!thi->reset_cpu_mask)
		return;
	thi->reset_cpu_mask = 0;
	set_cpus_allowed_ptr(p, resource->cpu_mask);
}
#else
#define drbd_calc_cpu_mask(A) ({})
#endif

/**
 * drbd_header_size  -  size of a packet header
 *
 * The header size is a multiple of 8, so any payload following the header is
 * word aligned on 64-bit architectures.  (The bitmap send and receive code
 * relies on this.)
 */
unsigned int drbd_header_size(struct drbd_connection *connection)
{
	if (connection->agreed_pro_version >= 100) {
		BUILD_BUG_ON(!IS_ALIGNED(sizeof(struct p_header100), 8));
		return sizeof(struct p_header100);
	} else {
		BUILD_BUG_ON(sizeof(struct p_header80) !=
			     sizeof(struct p_header95));
		BUILD_BUG_ON(!IS_ALIGNED(sizeof(struct p_header80), 8));
		return sizeof(struct p_header80);
	}
}

static unsigned int prepare_header80(struct p_header80 *h, enum drbd_packet cmd, int size)
{
	h->magic   = cpu_to_be32(DRBD_MAGIC);
	h->command = cpu_to_be16(cmd);
	h->length  = cpu_to_be16(size);
	return sizeof(struct p_header80);
}

static unsigned int prepare_header95(struct p_header95 *h, enum drbd_packet cmd, int size)
{
	h->magic   = cpu_to_be16(DRBD_MAGIC_BIG);
	h->command = cpu_to_be16(cmd);
	h->length = cpu_to_be32(size);
	return sizeof(struct p_header95);
}

static unsigned int prepare_header100(struct p_header100 *h, enum drbd_packet cmd,
				      int size, int vnr)
{
	h->magic = cpu_to_be32(DRBD_MAGIC_100);
	h->volume = cpu_to_be16(vnr);
	h->command = cpu_to_be16(cmd);
	h->length = cpu_to_be32(size);
	h->pad = 0;
	return sizeof(struct p_header100);
}

static unsigned int prepare_header(struct drbd_connection *connection, int vnr,
				   void *buffer, enum drbd_packet cmd, int size)
{
	if (connection->agreed_pro_version >= 100)
		return prepare_header100(buffer, cmd, size, vnr);
	else if (connection->agreed_pro_version >= 95 &&
		 size > DRBD_MAX_SIZE_H80_PACKET)
		return prepare_header95(buffer, cmd, size);
	else
		return prepare_header80(buffer, cmd, size);
}

static void *__conn_prepare_command(struct drbd_connection *connection,
				    struct drbd_socket *sock)
{
	if (!sock->socket)
		return NULL;
	return sock->sbuf + drbd_header_size(connection);
}

void *conn_prepare_command(struct drbd_connection *connection, struct drbd_socket *sock)
{
	void *p;

	mutex_lock(&sock->mutex);
	p = __conn_prepare_command(connection, sock);
	if (!p)
		mutex_unlock(&sock->mutex);

	return p;
}

void *drbd_prepare_command(struct drbd_peer_device *peer_device, struct drbd_socket *sock)
{
	return conn_prepare_command(peer_device->connection, sock);
}

static int __send_command(struct drbd_connection *connection, int vnr,
			  struct drbd_socket *sock, enum drbd_packet cmd,
			  unsigned int header_size, void *data,
			  unsigned int size)
{
	int msg_flags;
	int err;

	/*
	 * Called with @data == NULL and the size of the data blocks in @size
	 * for commands that send data blocks.  For those commands, omit the
	 * MSG_MORE flag: this will increase the likelihood that data blocks
	 * which are page aligned on the sender will end up page aligned on the
	 * receiver.
	 */
	msg_flags = data ? MSG_MORE : 0;

	header_size += prepare_header(connection, vnr, sock->sbuf, cmd,
				      header_size + size);
	err = drbd_send_all(connection, sock->socket, sock->sbuf, header_size,
			    msg_flags);
	if (data && !err)
		err = drbd_send_all(connection, sock->socket, data, size, 0);
	/* DRBD protocol "pings" are latency critical.
	 * This is supposed to trigger tcp_push_pending_frames() */
	if (!err && (cmd == P_PING || cmd == P_PING_ACK))
		drbd_tcp_nodelay(sock->socket);

	return err;
}

static int __conn_send_command(struct drbd_connection *connection, struct drbd_socket *sock,
			       enum drbd_packet cmd, unsigned int header_size,
			       void *data, unsigned int size)
{
	return __send_command(connection, 0, sock, cmd, header_size, data, size);
}

int conn_send_command(struct drbd_connection *connection, struct drbd_socket *sock,
		      enum drbd_packet cmd, unsigned int header_size,
		      void *data, unsigned int size)
{
	int err;

	err = __conn_send_command(connection, sock, cmd, header_size, data, size);
	mutex_unlock(&sock->mutex);
	return err;
}

int drbd_send_command(struct drbd_peer_device *peer_device, struct drbd_socket *sock,
		      enum drbd_packet cmd, unsigned int header_size,
		      void *data, unsigned int size)
{
	int err;

	err = __send_command(peer_device->connection, peer_device->device->vnr,
			     sock, cmd, header_size, data, size);
	mutex_unlock(&sock->mutex);
	return err;
}

int drbd_send_ping(struct drbd_connection *connection)
{
	struct drbd_socket *sock;

	sock = &connection->meta;
	if (!conn_prepare_command(connection, sock))
		return -EIO;
	return conn_send_command(connection, sock, P_PING, 0, NULL, 0);
}

int drbd_send_ping_ack(struct drbd_connection *connection)
{
	struct drbd_socket *sock;

	sock = &connection->meta;
	if (!conn_prepare_command(connection, sock))
		return -EIO;
	return conn_send_command(connection, sock, P_PING_ACK, 0, NULL, 0);
}

int drbd_send_sync_param(struct drbd_peer_device *peer_device)
{
	struct drbd_socket *sock;
	struct p_rs_param_95 *p;
	int size;
	const int apv = peer_device->connection->agreed_pro_version;
	enum drbd_packet cmd;
	struct net_conf *nc;
	struct disk_conf *dc;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;

	rcu_read_lock();
	nc = rcu_dereference(peer_device->connection->net_conf);

	size = apv <= 87 ? sizeof(struct p_rs_param)
		: apv == 88 ? sizeof(struct p_rs_param)
			+ strlen(nc->verify_alg) + 1
		: apv <= 94 ? sizeof(struct p_rs_param_89)
		: /* apv >= 95 */ sizeof(struct p_rs_param_95);

	cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;

	/* initialize verify_alg and csums_alg */
	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);

	if (get_ldev(peer_device->device)) {
		dc = rcu_dereference(peer_device->device->ldev->disk_conf);
		p->resync_rate = cpu_to_be32(dc->resync_rate);
		p->c_plan_ahead = cpu_to_be32(dc->c_plan_ahead);
		p->c_delay_target = cpu_to_be32(dc->c_delay_target);
		p->c_fill_target = cpu_to_be32(dc->c_fill_target);
		p->c_max_rate = cpu_to_be32(dc->c_max_rate);
		put_ldev(peer_device->device);
	} else {
		p->resync_rate = cpu_to_be32(DRBD_RESYNC_RATE_DEF);
		p->c_plan_ahead = cpu_to_be32(DRBD_C_PLAN_AHEAD_DEF);
		p->c_delay_target = cpu_to_be32(DRBD_C_DELAY_TARGET_DEF);
		p->c_fill_target = cpu_to_be32(DRBD_C_FILL_TARGET_DEF);
		p->c_max_rate = cpu_to_be32(DRBD_C_MAX_RATE_DEF);
	}

	if (apv >= 88)
		strcpy(p->verify_alg, nc->verify_alg);
	if (apv >= 89)
		strcpy(p->csums_alg, nc->csums_alg);
	rcu_read_unlock();

	return drbd_send_command(peer_device, sock, cmd, size, NULL, 0);
}

int __drbd_send_protocol(struct drbd_connection *connection, enum drbd_packet cmd)
{
	struct drbd_socket *sock;
	struct p_protocol *p;
	struct net_conf *nc;
	int size, cf;

	sock = &connection->data;
	p = __conn_prepare_command(connection, sock);
	if (!p)
		return -EIO;

	rcu_read_lock();
	nc = rcu_dereference(connection->net_conf);

	if (nc->tentative && connection->agreed_pro_version < 92) {
		rcu_read_unlock();
		mutex_unlock(&sock->mutex);
		drbd_err(connection, "--dry-run is not supported by peer");
		return -EOPNOTSUPP;
	}

	size = sizeof(*p);
	if (connection->agreed_pro_version >= 87)
		size += strlen(nc->integrity_alg) + 1;

	p->protocol      = cpu_to_be32(nc->wire_protocol);
	p->after_sb_0p   = cpu_to_be32(nc->after_sb_0p);
	p->after_sb_1p   = cpu_to_be32(nc->after_sb_1p);
	p->after_sb_2p   = cpu_to_be32(nc->after_sb_2p);
	p->two_primaries = cpu_to_be32(nc->two_primaries);
	cf = 0;
	if (nc->discard_my_data)
		cf |= CF_DISCARD_MY_DATA;
	if (nc->tentative)
		cf |= CF_DRY_RUN;
	p->conn_flags    = cpu_to_be32(cf);

	if (connection->agreed_pro_version >= 87)
		strcpy(p->integrity_alg, nc->integrity_alg);
	rcu_read_unlock();

	return __conn_send_command(connection, sock, cmd, size, NULL, 0);
}

int drbd_send_protocol(struct drbd_connection *connection)
{
	int err;

	mutex_lock(&connection->data.mutex);
	err = __drbd_send_protocol(connection, P_PROTOCOL);
	mutex_unlock(&connection->data.mutex);

	return err;
}

static int _drbd_send_uuids(struct drbd_peer_device *peer_device, u64 uuid_flags)
{
	struct drbd_device *device = peer_device->device;
	struct drbd_socket *sock;
	struct p_uuids *p;
	int i;

	if (!get_ldev_if_state(device, D_NEGOTIATING))
		return 0;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p) {
		put_ldev(device);
		return -EIO;
	}
	spin_lock_irq(&device->ldev->md.uuid_lock);
	for (i = UI_CURRENT; i < UI_SIZE; i++)
		p->uuid[i] = cpu_to_be64(device->ldev->md.uuid[i]);
	spin_unlock_irq(&device->ldev->md.uuid_lock);

	device->comm_bm_set = drbd_bm_total_weight(device);
	p->uuid[UI_SIZE] = cpu_to_be64(device->comm_bm_set);
	rcu_read_lock();
	uuid_flags |= rcu_dereference(peer_device->connection->net_conf)->discard_my_data ? 1 : 0;
	rcu_read_unlock();
	uuid_flags |= test_bit(CRASHED_PRIMARY, &device->flags) ? 2 : 0;
	uuid_flags |= device->new_state_tmp.disk == D_INCONSISTENT ? 4 : 0;
	p->uuid[UI_FLAGS] = cpu_to_be64(uuid_flags);

	put_ldev(device);
	return drbd_send_command(peer_device, sock, P_UUIDS, sizeof(*p), NULL, 0);
}

int drbd_send_uuids(struct drbd_peer_device *peer_device)
{
	return _drbd_send_uuids(peer_device, 0);
}

int drbd_send_uuids_skip_initial_sync(struct drbd_peer_device *peer_device)
{
	return _drbd_send_uuids(peer_device, 8);
}

void drbd_print_uuids(struct drbd_device *device, const char *text)
{
	if (get_ldev_if_state(device, D_NEGOTIATING)) {
		u64 *uuid = device->ldev->md.uuid;
		drbd_info(device, "%s %016llX:%016llX:%016llX:%016llX\n",
		     text,
		     (unsigned long long)uuid[UI_CURRENT],
		     (unsigned long long)uuid[UI_BITMAP],
		     (unsigned long long)uuid[UI_HISTORY_START],
		     (unsigned long long)uuid[UI_HISTORY_END]);
		put_ldev(device);
	} else {
		drbd_info(device, "%s effective data uuid: %016llX\n",
				text,
				(unsigned long long)device->ed_uuid);
	}
}

void drbd_gen_and_send_sync_uuid(struct drbd_peer_device *peer_device)
{
	struct drbd_device *device = peer_device->device;
	struct drbd_socket *sock;
	struct p_rs_uuid *p;
	u64 uuid;

	D_ASSERT(device, device->state.disk == D_UP_TO_DATE);

	uuid = device->ldev->md.uuid[UI_BITMAP];
	if (uuid && uuid != UUID_JUST_CREATED)
		uuid = uuid + UUID_NEW_BM_OFFSET;
	else
		get_random_bytes(&uuid, sizeof(u64));
	drbd_uuid_set(device, UI_BITMAP, uuid);
	drbd_print_uuids(device, "updated sync UUID");
	drbd_md_sync(device);

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (p) {
		p->uuid = cpu_to_be64(uuid);
		drbd_send_command(peer_device, sock, P_SYNC_UUID, sizeof(*p), NULL, 0);
	}
}

/* communicated if (agreed_features & DRBD_FF_WSAME) */
void assign_p_sizes_qlim(struct drbd_device *device, struct p_sizes *p, struct request_queue *q)
{
	if (q) {
		p->qlim->physical_block_size = cpu_to_be32(queue_physical_block_size(q));
		p->qlim->logical_block_size = cpu_to_be32(queue_logical_block_size(q));
		p->qlim->alignment_offset = cpu_to_be32(queue_alignment_offset(q));
		p->qlim->io_min = cpu_to_be32(queue_io_min(q));
		p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
		p->qlim->discard_enabled = blk_queue_discard(q);
		p->qlim->discard_zeroes_data = queue_discard_zeroes_data(q);
		p->qlim->write_same_capable = !!q->limits.max_write_same_sectors;
	} else {
		q = device->rq_queue;
		p->qlim->physical_block_size = cpu_to_be32(queue_physical_block_size(q));
		p->qlim->logical_block_size = cpu_to_be32(queue_logical_block_size(q));
		p->qlim->alignment_offset = 0;
		p->qlim->io_min = cpu_to_be32(queue_io_min(q));
		p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
		p->qlim->discard_enabled = 0;
		p->qlim->discard_zeroes_data = 0;
		p->qlim->write_same_capable = 0;
	}
}

int drbd_send_sizes(struct drbd_peer_device *peer_device, int trigger_reply, enum dds_flags flags)
{
	struct drbd_device *device = peer_device->device;
	struct drbd_socket *sock;
	struct p_sizes *p;
	sector_t d_size, u_size;
	int q_order_type;
	unsigned int max_bio_size;
	unsigned int packet_size;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;

	packet_size = sizeof(*p);
	if (peer_device->connection->agreed_features & DRBD_FF_WSAME)
		packet_size += sizeof(p->qlim[0]);

	memset(p, 0, packet_size);
	if (get_ldev_if_state(device, D_NEGOTIATING)) {
		struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
		d_size = drbd_get_max_capacity(device->ldev);
		rcu_read_lock();
		u_size = rcu_dereference(device->ldev->disk_conf)->disk_size;
		rcu_read_unlock();
		q_order_type = drbd_queue_order_type(device);
		max_bio_size = queue_max_hw_sectors(q) << 9;
		max_bio_size = min(max_bio_size, DRBD_MAX_BIO_SIZE);
		assign_p_sizes_qlim(device, p, q);
		put_ldev(device);
	} else {
		d_size = 0;
		u_size = 0;
		q_order_type = QUEUE_ORDERED_NONE;
		max_bio_size = DRBD_MAX_BIO_SIZE; /* ... multiple BIOs per peer_request */
		assign_p_sizes_qlim(device, p, NULL);
	}

	if (peer_device->connection->agreed_pro_version <= 94)
		max_bio_size = min(max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
	else if (peer_device->connection->agreed_pro_version < 100)
		max_bio_size = min(max_bio_size, DRBD_MAX_BIO_SIZE_P95);

	p->d_size = cpu_to_be64(d_size);
	p->u_size = cpu_to_be64(u_size);
	p->c_size = cpu_to_be64(trigger_reply ? 0 : drbd_get_capacity(device->this_bdev));
	p->max_bio_size = cpu_to_be32(max_bio_size);
	p->queue_order_type = cpu_to_be16(q_order_type);
	p->dds_flags = cpu_to_be16(flags);

	return drbd_send_command(peer_device, sock, P_SIZES, packet_size, NULL, 0);
}

/**
 * drbd_send_current_state() - Sends the drbd state to the peer
 * @peer_device:	DRBD peer device.
 */
int drbd_send_current_state(struct drbd_peer_device *peer_device)
{
	struct drbd_socket *sock;
	struct p_state *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->state = cpu_to_be32(peer_device->device->state.i); /* Within the send mutex */
	return drbd_send_command(peer_device, sock, P_STATE, sizeof(*p), NULL, 0);
}

/**
 * drbd_send_state() - After a state change, sends the new state to the peer
 * @peer_device:      DRBD peer device.
 * @state:     the state to send, not necessarily the current state.
 *
 * Each state change queues an "after_state_ch" work, which will eventually
 * send the resulting new state to the peer. If more state changes happen
 * between queuing and processing of the after_state_ch work, we still
 * want to send each intermediary state in the order it occurred.
 */
int drbd_send_state(struct drbd_peer_device *peer_device, union drbd_state state)
{
	struct drbd_socket *sock;
	struct p_state *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->state = cpu_to_be32(state.i); /* Within the send mutex */
	return drbd_send_command(peer_device, sock, P_STATE, sizeof(*p), NULL, 0);
}

int drbd_send_state_req(struct drbd_peer_device *peer_device, union drbd_state mask, union drbd_state val)
{
	struct drbd_socket *sock;
	struct p_req_state *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->mask = cpu_to_be32(mask.i);
	p->val = cpu_to_be32(val.i);
	return drbd_send_command(peer_device, sock, P_STATE_CHG_REQ, sizeof(*p), NULL, 0);
}

int conn_send_state_req(struct drbd_connection *connection, union drbd_state mask, union drbd_state val)
{
	enum drbd_packet cmd;
	struct drbd_socket *sock;
	struct p_req_state *p;

	cmd = connection->agreed_pro_version < 100 ? P_STATE_CHG_REQ : P_CONN_ST_CHG_REQ;
	sock = &connection->data;
	p = conn_prepare_command(connection, sock);
	if (!p)
		return -EIO;
	p->mask = cpu_to_be32(mask.i);
	p->val = cpu_to_be32(val.i);
	return conn_send_command(connection, sock, cmd, sizeof(*p), NULL, 0);
}

void drbd_send_sr_reply(struct drbd_peer_device *peer_device, enum drbd_state_rv retcode)
{
	struct drbd_socket *sock;
	struct p_req_state_reply *p;

	sock = &peer_device->connection->meta;
	p = drbd_prepare_command(peer_device, sock);
	if (p) {
		p->retcode = cpu_to_be32(retcode);
		drbd_send_command(peer_device, sock, P_STATE_CHG_REPLY, sizeof(*p), NULL, 0);
	}
}

void conn_send_sr_reply(struct drbd_connection *connection, enum drbd_state_rv retcode)
{
	struct drbd_socket *sock;
	struct p_req_state_reply *p;
	enum drbd_packet cmd = connection->agreed_pro_version < 100 ? P_STATE_CHG_REPLY : P_CONN_ST_CHG_REPLY;

	sock = &connection->meta;
	p = conn_prepare_command(connection, sock);
	if (p) {
		p->retcode = cpu_to_be32(retcode);
		conn_send_command(connection, sock, cmd, sizeof(*p), NULL, 0);
	}
}

static void dcbp_set_code(struct p_compressed_bm *p, enum drbd_bitmap_code code)
{
	BUG_ON(code & ~0xf);
	p->encoding = (p->encoding & ~0xf) | code;
}

static void dcbp_set_start(struct p_compressed_bm *p, int set)
{
	p->encoding = (p->encoding & ~0x80) | (set ? 0x80 : 0);
}

static void dcbp_set_pad_bits(struct p_compressed_bm *p, int n)
{
	BUG_ON(n & ~0x7);
	p->encoding = (p->encoding & (~0x7 << 4)) | (n << 4);
}

static int fill_bitmap_rle_bits(struct drbd_device *device,
			 struct p_compressed_bm *p,
			 unsigned int size,
			 struct bm_xfer_ctx *c)
{
	struct bitstream bs;
	unsigned long plain_bits;
	unsigned long tmp;
	unsigned long rl;
	unsigned len;
	unsigned toggle;
	int bits, use_rle;

	/* may we use this feature? */
	rcu_read_lock();
	use_rle = rcu_dereference(first_peer_device(device)->connection->net_conf)->use_rle;
	rcu_read_unlock();
	if (!use_rle || first_peer_device(device)->connection->agreed_pro_version < 90)
		return 0;

	if (c->bit_offset >= c->bm_bits)
		return 0; /* nothing to do. */

	/* use at most thus many bytes */
	bitstream_init(&bs, p->code, size, 0);
	memset(p->code, 0, size);
	/* plain bits covered in this code string */
	plain_bits = 0;

	/* p->encoding & 0x80 stores whether the first run length is set.
	 * bit offset is implicit.
	 * start with toggle == 2 to be able to tell the first iteration */
	toggle = 2;

	/* see how much plain bits we can stuff into one packet
	 * using RLE and VLI. */
	do {
		tmp = (toggle == 0) ? _drbd_bm_find_next_zero(device, c->bit_offset)
				    : _drbd_bm_find_next(device, c->bit_offset);
		if (tmp == -1UL)
			tmp = c->bm_bits;
		rl = tmp - c->bit_offset;

		if (toggle == 2) { /* first iteration */
			if (rl == 0) {
				/* the first checked bit was set,
				 * store start value, */
				dcbp_set_start(p, 1);
				/* but skip encoding of zero run length */
				toggle = !toggle;
				continue;
			}
			dcbp_set_start(p, 0);
		}

		/* paranoia: catch zero runlength.
		 * can only happen if bitmap is modified while we scan it. */
		if (rl == 0) {
			drbd_err(device, "unexpected zero runlength while encoding bitmap "
			    "t:%u bo:%lu\n", toggle, c->bit_offset);
			return -1;
		}

		bits = vli_encode_bits(&bs, rl);
		if (bits == -ENOBUFS) /* buffer full */
			break;
		if (bits <= 0) {
			drbd_err(device, "error while encoding bitmap: %d\n", bits);
			return 0;
		}

		toggle = !toggle;
		plain_bits += rl;
		c->bit_offset = tmp;
	} while (c->bit_offset < c->bm_bits);

	len = bs.cur.b - p->code + !!bs.cur.bit;

	if (plain_bits < (len << 3)) {
		/* incompressible with this method.
		 * we need to rewind both word and bit position. */
		c->bit_offset -= plain_bits;
		bm_xfer_ctx_bit_to_word_offset(c);
		c->bit_offset = c->word_offset * BITS_PER_LONG;
		return 0;
	}

	/* RLE + VLI was able to compress it just fine.
	 * update c->word_offset. */
	bm_xfer_ctx_bit_to_word_offset(c);

	/* store pad_bits */
	dcbp_set_pad_bits(p, (8 - bs.cur.bit) & 0x7);

	return len;
}

/**
 * send_bitmap_rle_or_plain
 *
 * Return 0 when done, 1 when another iteration is needed, and a negative error
 * code upon failure.
 */
static int
send_bitmap_rle_or_plain(struct drbd_device *device, struct bm_xfer_ctx *c)
{
	struct drbd_socket *sock = &first_peer_device(device)->connection->data;
	unsigned int header_size = drbd_header_size(first_peer_device(device)->connection);
	struct p_compressed_bm *p = sock->sbuf + header_size;
	int len, err;

	len = fill_bitmap_rle_bits(device, p,
			DRBD_SOCKET_BUFFER_SIZE - header_size - sizeof(*p), c);
	if (len < 0)
		return -EIO;

	if (len) {
		dcbp_set_code(p, RLE_VLI_Bits);
		err = __send_command(first_peer_device(device)->connection, device->vnr, sock,
				     P_COMPRESSED_BITMAP, sizeof(*p) + len,
				     NULL, 0);
		c->packets[0]++;
		c->bytes[0] += header_size + sizeof(*p) + len;

		if (c->bit_offset >= c->bm_bits)
			len = 0; /* DONE */
	} else {
		/* was not compressible.
		 * send a buffer full of plain text bits instead. */
		unsigned int data_size;
		unsigned long num_words;
		unsigned long *p = sock->sbuf + header_size;

		data_size = DRBD_SOCKET_BUFFER_SIZE - header_size;
		num_words = min_t(size_t, data_size / sizeof(*p),
				  c->bm_words - c->word_offset);
		len = num_words * sizeof(*p);
		if (len)
			drbd_bm_get_lel(device, c->word_offset, num_words, p);
		err = __send_command(first_peer_device(device)->connection, device->vnr, sock, P_BITMAP, len, NULL, 0);
		c->word_offset += num_words;
		c->bit_offset = c->word_offset * BITS_PER_LONG;

		c->packets[1]++;
		c->bytes[1] += header_size + len;

		if (c->bit_offset > c->bm_bits)
			c->bit_offset = c->bm_bits;
	}
	if (!err) {
		if (len == 0) {
			INFO_bm_xfer_stats(device, "send", c);
			return 0;
		} else
			return 1;
	}
	return -EIO;
}

/* See the comment at receive_bitmap() */
static int _drbd_send_bitmap(struct drbd_device *device)
{
	struct bm_xfer_ctx c;
	int err;

	if (!expect(device->bitmap))
		return false;

	if (get_ldev(device)) {
		if (drbd_md_test_flag(device->ldev, MDF_FULL_SYNC)) {
			drbd_info(device, "Writing the whole bitmap, MDF_FullSync was set.\n");
			drbd_bm_set_all(device);
			if (drbd_bm_write(device)) {
				/* write_bm did fail! Leave full sync flag set in Meta P_DATA
				 * but otherwise process as per normal - need to tell other
				 * side that a full resync is required! */
				drbd_err(device, "Failed to write bitmap to disk!\n");
			} else {
				drbd_md_clear_flag(device, MDF_FULL_SYNC);
				drbd_md_sync(device);
			}
		}
		put_ldev(device);
	}

	c = (struct bm_xfer_ctx) {
		.bm_bits = drbd_bm_bits(device),
		.bm_words = drbd_bm_words(device),
	};

	do {
		err = send_bitmap_rle_or_plain(device, &c);
	} while (err > 0);

	return err == 0;
}

int drbd_send_bitmap(struct drbd_device *device)
{
	struct drbd_socket *sock = &first_peer_device(device)->connection->data;
	int err = -1;

	mutex_lock(&sock->mutex);
	if (sock->socket)
		err = !_drbd_send_bitmap(device);
	mutex_unlock(&sock->mutex);
	return err;
}

void drbd_send_b_ack(struct drbd_connection *connection, u32 barrier_nr, u32 set_size)
{
	struct drbd_socket *sock;
	struct p_barrier_ack *p;

	if (connection->cstate < C_WF_REPORT_PARAMS)
		return;

	sock = &connection->meta;
	p = conn_prepare_command(connection, sock);
	if (!p)
		return;
	p->barrier = barrier_nr;
	p->set_size = cpu_to_be32(set_size);
	conn_send_command(connection, sock, P_BARRIER_ACK, sizeof(*p), NULL, 0);
}

/**
 * _drbd_send_ack() - Sends an ack packet
 * @device:	DRBD device.
 * @cmd:	Packet command code.
 * @sector:	sector, needs to be in big endian byte order
 * @blksize:	size in byte, needs to be in big endian byte order
 * @block_id:	Id, big endian byte order
 */
static int _drbd_send_ack(struct drbd_peer_device *peer_device, enum drbd_packet cmd,
			  u64 sector, u32 blksize, u64 block_id)
{
	struct drbd_socket *sock;
	struct p_block_ack *p;

	if (peer_device->device->state.conn < C_CONNECTED)
		return -EIO;

	sock = &peer_device->connection->meta;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->sector = sector;
	p->block_id = block_id;
	p->blksize = blksize;
	p->seq_num = cpu_to_be32(atomic_inc_return(&peer_device->device->packet_seq));
	return drbd_send_command(peer_device, sock, cmd, sizeof(*p), NULL, 0);
}

/* dp->sector and dp->block_id already/still in network byte order,
 * data_size is payload size according to dp->head,
 * and may need to be corrected for digest size. */
void drbd_send_ack_dp(struct drbd_peer_device *peer_device, enum drbd_packet cmd,
		      struct p_data *dp, int data_size)
{
	if (peer_device->connection->peer_integrity_tfm)
		data_size -= crypto_ahash_digestsize(peer_device->connection->peer_integrity_tfm);
	_drbd_send_ack(peer_device, cmd, dp->sector, cpu_to_be32(data_size),
		       dp->block_id);
}

void drbd_send_ack_rp(struct drbd_peer_device *peer_device, enum drbd_packet cmd,
		      struct p_block_req *rp)
{
	_drbd_send_ack(peer_device, cmd, rp->sector, rp->blksize, rp->block_id);
}

/**
 * drbd_send_ack() - Sends an ack packet
 * @device:	DRBD device
 * @cmd:	packet command code
 * @peer_req:	peer request
 */
int drbd_send_ack(struct drbd_peer_device *peer_device, enum drbd_packet cmd,
		  struct drbd_peer_request *peer_req)
{
	return _drbd_send_ack(peer_device, cmd,
			      cpu_to_be64(peer_req->i.sector),
			      cpu_to_be32(peer_req->i.size),
			      peer_req->block_id);
}

/* This function misuses the block_id field to signal if the blocks
 * are is sync or not. */
int drbd_send_ack_ex(struct drbd_peer_device *peer_device, enum drbd_packet cmd,
		     sector_t sector, int blksize, u64 block_id)
{
	return _drbd_send_ack(peer_device, cmd,
			      cpu_to_be64(sector),
			      cpu_to_be32(blksize),
			      cpu_to_be64(block_id));
}

int drbd_send_rs_deallocated(struct drbd_peer_device *peer_device,
			     struct drbd_peer_request *peer_req)
{
	struct drbd_socket *sock;
	struct p_block_desc *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(peer_req->i.sector);
	p->blksize = cpu_to_be32(peer_req->i.size);
	p->pad = 0;
	return drbd_send_command(peer_device, sock, P_RS_DEALLOCATED, sizeof(*p), NULL, 0);
}

int drbd_send_drequest(struct drbd_peer_device *peer_device, int cmd,
		       sector_t sector, int size, u64 block_id)
{
	struct drbd_socket *sock;
	struct p_block_req *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(sector);
	p->block_id = block_id;
	p->blksize = cpu_to_be32(size);
	return drbd_send_command(peer_device, sock, cmd, sizeof(*p), NULL, 0);
}

int drbd_send_drequest_csum(struct drbd_peer_device *peer_device, sector_t sector, int size,
			    void *digest, int digest_size, enum drbd_packet cmd)
{
	struct drbd_socket *sock;
	struct p_block_req *p;

	/* FIXME: Put the digest into the preallocated socket buffer.  */

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(sector);
	p->block_id = ID_SYNCER /* unused */;
	p->blksize = cpu_to_be32(size);
	return drbd_send_command(peer_device, sock, cmd, sizeof(*p), digest, digest_size);
}

int drbd_send_ov_request(struct drbd_peer_device *peer_device, sector_t sector, int size)
{
	struct drbd_socket *sock;
	struct p_block_req *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(sector);
	p->block_id = ID_SYNCER /* unused */;
	p->blksize = cpu_to_be32(size);
	return drbd_send_command(peer_device, sock, P_OV_REQUEST, sizeof(*p), NULL, 0);
}

/* called on sndtimeo
 * returns false if we should retry,
 * true if we think connection is dead
 */
static int we_should_drop_the_connection(struct drbd_connection *connection, struct socket *sock)
{
	int drop_it;
	/* long elapsed = (long)(jiffies - device->last_received); */

	drop_it =   connection->meta.socket == sock
		|| !connection->ack_receiver.task
		|| get_t_state(&connection->ack_receiver) != RUNNING
		|| connection->cstate < C_WF_REPORT_PARAMS;

	if (drop_it)
		return true;

	drop_it = !--connection->ko_count;
	if (!drop_it) {
		drbd_err(connection, "[%s/%d] sock_sendmsg time expired, ko = %u\n",
			 current->comm, current->pid, connection->ko_count);
		request_ping(connection);
	}

	return drop_it; /* && (device->state == R_PRIMARY) */;
}

static void drbd_update_congested(struct drbd_connection *connection)
{
	struct sock *sk = connection->data.socket->sk;
	if (sk->sk_wmem_queued > sk->sk_sndbuf * 4 / 5)
		set_bit(NET_CONGESTED, &connection->flags);
}

/* The idea of sendpage seems to be to put some kind of reference
 * to the page into the skb, and to hand it over to the NIC. In
 * this process get_page() gets called.
 *
 * As soon as the page was really sent over the network put_page()
 * gets called by some part of the network layer. [ NIC driver? ]
 *
 * [ get_page() / put_page() increment/decrement the count. If count
 *   reaches 0 the page will be freed. ]
 *
 * This works nicely with pages from FSs.
 * But this means that in protocol A we might signal IO completion too early!
 *
 * In order not to corrupt data during a resync we must make sure
 * that we do not reuse our own buffer pages (EEs) to early, therefore
 * we have the net_ee list.
 *
 * XFS seems to have problems, still, it submits pages with page_count == 0!
 * As a workaround, we disable sendpage on pages
 * with page_count == 0 or PageSlab.
 */
static int _drbd_no_send_page(struct drbd_peer_device *peer_device, struct page *page,
			      int offset, size_t size, unsigned msg_flags)
{
	struct socket *socket;
	void *addr;
	int err;

	socket = peer_device->connection->data.socket;
	addr = kmap(page) + offset;
	err = drbd_send_all(peer_device->connection, socket, addr, size, msg_flags);
	kunmap(page);
	if (!err)
		peer_device->device->send_cnt += size >> 9;
	return err;
}

static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *page,
		    int offset, size_t size, unsigned msg_flags)
{
	struct socket *socket = peer_device->connection->data.socket;
	mm_segment_t oldfs = get_fs();
	int len = size;
	int err = -EIO;

	/* e.g. XFS meta- & log-data is in slab pages, which have a
	 * page_count of 0 and/or have PageSlab() set.
	 * we cannot use send_page for those, as that does get_page();
	 * put_page(); and would cause either a VM_BUG directly, or
	 * __page_cache_release a page that would actually still be referenced
	 * by someone, leading to some obscure delayed Oops somewhere else. */
	if (disable_sendpage || (page_count(page) < 1) || PageSlab(page))
		return _drbd_no_send_page(peer_device, page, offset, size, msg_flags);

	msg_flags |= MSG_NOSIGNAL;
	drbd_update_congested(peer_device->connection);
	set_fs(KERNEL_DS);
	do {
		int sent;

		sent = socket->ops->sendpage(socket, page, offset, len, msg_flags);
		if (sent <= 0) {
			if (sent == -EAGAIN) {
				if (we_should_drop_the_connection(peer_device->connection, socket))
					break;
				continue;
			}
			drbd_warn(peer_device->device, "%s: size=%d len=%d sent=%d\n",
			     __func__, (int)size, len, sent);
			if (sent < 0)
				err = sent;
			break;
		}
		len    -= sent;
		offset += sent;
	} while (len > 0 /* THINK && device->cstate >= C_CONNECTED*/);
	set_fs(oldfs);
	clear_bit(NET_CONGESTED, &peer_device->connection->flags);

	if (len == 0) {
		err = 0;
		peer_device->device->send_cnt += size >> 9;
	}
	return err;
}

static int _drbd_send_bio(struct drbd_peer_device *peer_device, struct bio *bio)
{
	struct bio_vec bvec;
	struct bvec_iter iter;

	/* hint all but last page with MSG_MORE */
	bio_for_each_segment(bvec, bio, iter) {
		int err;

		err = _drbd_no_send_page(peer_device, bvec.bv_page,
					 bvec.bv_offset, bvec.bv_len,
					 bio_iter_last(bvec, iter)
					 ? 0 : MSG_MORE);
		if (err)
			return err;
		/* REQ_OP_WRITE_SAME has only one segment */
		if (bio_op(bio) == REQ_OP_WRITE_SAME)
			break;
	}
	return 0;
}

static int _drbd_send_zc_bio(struct drbd_peer_device *peer_device, struct bio *bio)
{
	struct bio_vec bvec;
	struct bvec_iter iter;

	/* hint all but last page with MSG_MORE */
	bio_for_each_segment(bvec, bio, iter) {
		int err;

		err = _drbd_send_page(peer_device, bvec.bv_page,
				      bvec.bv_offset, bvec.bv_len,
				      bio_iter_last(bvec, iter) ? 0 : MSG_MORE);
		if (err)
			return err;
		/* REQ_OP_WRITE_SAME has only one segment */
		if (bio_op(bio) == REQ_OP_WRITE_SAME)
			break;
	}
	return 0;
}

static int _drbd_send_zc_ee(struct drbd_peer_device *peer_device,
			    struct drbd_peer_request *peer_req)
{
	struct page *page = peer_req->pages;
	unsigned len = peer_req->i.size;
	int err;

	/* hint all but last page with MSG_MORE */
	page_chain_for_each(page) {
		unsigned l = min_t(unsigned, len, PAGE_SIZE);

		err = _drbd_send_page(peer_device, page, 0, l,
				      page_chain_next(page) ? MSG_MORE : 0);
		if (err)
			return err;
		len -= l;
	}
	return 0;
}

static u32 bio_flags_to_wire(struct drbd_connection *connection,
			     struct bio *bio)
{
	if (connection->agreed_pro_version >= 95)
		return  (bio->bi_opf & REQ_SYNC ? DP_RW_SYNC : 0) |
			(bio->bi_opf & REQ_FUA ? DP_FUA : 0) |
			(bio->bi_opf & REQ_PREFLUSH ? DP_FLUSH : 0) |
			(bio_op(bio) == REQ_OP_WRITE_SAME ? DP_WSAME : 0) |
			(bio_op(bio) == REQ_OP_DISCARD ? DP_DISCARD : 0);
	else
		return bio->bi_opf & REQ_SYNC ? DP_RW_SYNC : 0;
}

/* Used to send write or TRIM aka REQ_DISCARD requests
 * R_PRIMARY -> Peer	(P_DATA, P_TRIM)
 */
int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request *req)
{
	struct drbd_device *device = peer_device->device;
	struct drbd_socket *sock;
	struct p_data *p;
	struct p_wsame *wsame = NULL;
	void *digest_out;
	unsigned int dp_flags = 0;
	int digest_size;
	int err;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	digest_size = peer_device->connection->integrity_tfm ?
		      crypto_ahash_digestsize(peer_device->connection->integrity_tfm) : 0;

	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(req->i.sector);
	p->block_id = (unsigned long)req;
	p->seq_num = cpu_to_be32(atomic_inc_return(&device->packet_seq));
	dp_flags = bio_flags_to_wire(peer_device->connection, req->master_bio);
	if (device->state.conn >= C_SYNC_SOURCE &&
	    device->state.conn <= C_PAUSED_SYNC_T)
		dp_flags |= DP_MAY_SET_IN_SYNC;
	if (peer_device->connection->agreed_pro_version >= 100) {
		if (req->rq_state & RQ_EXP_RECEIVE_ACK)
			dp_flags |= DP_SEND_RECEIVE_ACK;
		/* During resync, request an explicit write ack,
		 * even in protocol != C */
		if (req->rq_state & RQ_EXP_WRITE_ACK
		|| (dp_flags & DP_MAY_SET_IN_SYNC))
			dp_flags |= DP_SEND_WRITE_ACK;
	}
	p->dp_flags = cpu_to_be32(dp_flags);

	if (dp_flags & DP_DISCARD) {
		struct p_trim *t = (struct p_trim*)p;
		t->size = cpu_to_be32(req->i.size);
		err = __send_command(peer_device->connection, device->vnr, sock, P_TRIM, sizeof(*t), NULL, 0);
		goto out;
	}
	if (dp_flags & DP_WSAME) {
		/* this will only work if DRBD_FF_WSAME is set AND the
		 * handshake agreed that all nodes and backend devices are
		 * WRITE_SAME capable and agree on logical_block_size */
		wsame = (struct p_wsame*)p;
		digest_out = wsame + 1;
		wsame->size = cpu_to_be32(req->i.size);
	} else
		digest_out = p + 1;

	/* our digest is still only over the payload.
	 * TRIM does not carry any payload. */
	if (digest_size)
		drbd_csum_bio(peer_device->connection->integrity_tfm, req->master_bio, digest_out);
	if (wsame) {
		err =
		    __send_command(peer_device->connection, device->vnr, sock, P_WSAME,
				   sizeof(*wsame) + digest_size, NULL,
				   bio_iovec(req->master_bio).bv_len);
	} else
		err =
		    __send_command(peer_device->connection, device->vnr, sock, P_DATA,
				   sizeof(*p) + digest_size, NULL, req->i.size);
	if (!err) {
		/* For protocol A, we have to memcpy the payload into
		 * socket buffers, as we may complete right away
		 * as soon as we handed it over to tcp, at which point the data
		 * pages may become invalid.
		 *
		 * For data-integrity enabled, we copy it as well, so we can be
		 * sure that even if the bio pages may still be modified, it
		 * won't change the data on the wire, thus if the digest checks
		 * out ok after sending on this side, but does not fit on the
		 * receiving side, we sure have detected corruption elsewhere.
		 */
		if (!(req->rq_state & (RQ_EXP_RECEIVE_ACK | RQ_EXP_WRITE_ACK)) || digest_size)
			err = _drbd_send_bio(peer_device, req->master_bio);
		else
			err = _drbd_send_zc_bio(peer_device, req->master_bio);

		/* double check digest, sometimes buffers have been modified in flight. */
		if (digest_size > 0 && digest_size <= 64) {
			/* 64 byte, 512 bit, is the largest digest size
			 * currently supported in kernel crypto. */
			unsigned char digest[64];
			drbd_csum_bio(peer_device->connection->integrity_tfm, req->master_bio, digest);
			if (memcmp(p + 1, digest, digest_size)) {
				drbd_warn(device,
					"Digest mismatch, buffer modified by upper layers during write: %llus +%u\n",
					(unsigned long long)req->i.sector, req->i.size);
			}
		} /* else if (digest_size > 64) {
		     ... Be noisy about digest too large ...
		} */
	}
out:
	mutex_unlock(&sock->mutex);  /* locked by drbd_prepare_command() */

	return err;
}

/* answer packet, used to send data back for read requests:
 *  Peer       -> (diskless) R_PRIMARY   (P_DATA_REPLY)
 *  C_SYNC_SOURCE -> C_SYNC_TARGET         (P_RS_DATA_REPLY)
 */
int drbd_send_block(struct drbd_peer_device *peer_device, enum drbd_packet cmd,
		    struct drbd_peer_request *peer_req)
{
	struct drbd_device *device = peer_device->device;
	struct drbd_socket *sock;
	struct p_data *p;
	int err;
	int digest_size;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);

	digest_size = peer_device->connection->integrity_tfm ?
		      crypto_ahash_digestsize(peer_device->connection->integrity_tfm) : 0;

	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(peer_req->i.sector);
	p->block_id = peer_req->block_id;
	p->seq_num = 0;  /* unused */
	p->dp_flags = 0;
	if (digest_size)
		drbd_csum_ee(peer_device->connection->integrity_tfm, peer_req, p + 1);
	err = __send_command(peer_device->connection, device->vnr, sock, cmd, sizeof(*p) + digest_size, NULL, peer_req->i.size);
	if (!err)
		err = _drbd_send_zc_ee(peer_device, peer_req);
	mutex_unlock(&sock->mutex);  /* locked by drbd_prepare_command() */

	return err;
}

int drbd_send_out_of_sync(struct drbd_peer_device *peer_device, struct drbd_request *req)
{
	struct drbd_socket *sock;
	struct p_block_desc *p;

	sock = &peer_device->connection->data;
	p = drbd_prepare_command(peer_device, sock);
	if (!p)
		return -EIO;
	p->sector = cpu_to_be64(req->i.sector);
	p->blksize = cpu_to_be32(req->i.size);
	return drbd_send_command(peer_device, sock, P_OUT_OF_SYNC, sizeof(*p), NULL, 0);
}

/*
  drbd_send distinguishes two cases:

  Packets sent via the data socket "sock"
  and packets sent via the meta data socket "msock"

		    sock                      msock
  -----------------+-------------------------+------------------------------
  timeout           conf.timeout / 2          conf.timeout / 2
  timeout action    send a ping via msock     Abort communication
					      and close all sockets
*/

/*
 * you must have down()ed the appropriate [m]sock_mutex elsewhere!
 */
int drbd_send(struct drbd_connection *connection, struct socket *sock,
	      void *buf, size_t size, unsigned msg_flags)
{
	struct kvec iov;
	struct msghdr msg;
	int rv, sent = 0;

	if (!sock)
		return -EBADR;

	/* THINK  if (signal_pending) return ... ? */

	iov.iov_base = buf;
	iov.iov_len  = size;

	msg.msg_name       = NULL;
	msg.msg_namelen    = 0;
	msg.msg_control    = NULL;
	msg.msg_controllen = 0;
	msg.msg_flags      = msg_flags | MSG_NOSIGNAL;

	if (sock == connection->data.socket) {
		rcu_read_lock();
		connection->ko_count = rcu_dereference(connection->net_conf)->ko_count;
		rcu_read_unlock();
		drbd_update_congested(connection);
	}
	do {
		rv = kernel_sendmsg(sock, &msg, &iov, 1, size);
		if (rv == -EAGAIN) {
			if (we_should_drop_the_connection(connection, sock))
				break;
			else
				continue;
		}
		if (rv == -EINTR) {
			flush_signals(current);
			rv = 0;
		}
		if (rv < 0)
			break;
		sent += rv;
		iov.iov_base += rv;
		iov.iov_len  -= rv;
	} while (sent < size);

	if (sock == connection->data.socket)
		clear_bit(NET_CONGESTED, &connection->flags);

	if (rv <= 0) {
		if (rv != -EAGAIN) {
			drbd_err(connection, "%s_sendmsg returned %d\n",
				 sock == connection->meta.socket ? "msock" : "sock",
				 rv);
			conn_request_state(connection, NS(conn, C_BROKEN_PIPE), CS_HARD);
		} else
			conn_request_state(connection, NS(conn, C_TIMEOUT), CS_HARD);
	}

	return sent;
}

/**
 * drbd_send_all  -  Send an entire buffer
 *
 * Returns 0 upon success and a negative error value otherwise.
 */
int drbd_send_all(struct drbd_connection *connection, struct socket *sock, void *buffer,
		  size_t size, unsigned msg_flags)
{
	int err;

	err = drbd_send(connection, sock, buffer, size, msg_flags);
	if (err < 0)
		return err;
	if (err != size)
		return -EIO;
	return 0;
}

static int drbd_open(struct block_device *bdev, fmode_t mode)
{
	struct drbd_device *device = bdev->bd_disk->private_data;
	unsigned long flags;
	int rv = 0;

	mutex_lock(&drbd_main_mutex);
	spin_lock_irqsave(&device->resource->req_lock, flags);
	/* to have a stable device->state.role
	 * and no race with updating open_cnt */

	if (device->state.role != R_PRIMARY) {
		if (mode & FMODE_WRITE)
			rv = -EROFS;
		else if (!allow_oos)
			rv = -EMEDIUMTYPE;
	}

	if (!rv)
		device->open_cnt++;
	spin_unlock_irqrestore(&device->resource->req_lock, flags);
	mutex_unlock(&drbd_main_mutex);

	return rv;
}

static void drbd_release(struct gendisk *gd, fmode_t mode)
{
	struct drbd_device *device = gd->private_data;
	mutex_lock(&drbd_main_mutex);
	device->open_cnt--;
	mutex_unlock(&drbd_main_mutex);
}

static void drbd_set_defaults(struct drbd_device *device)
{
	/* Beware! The actual layout differs
	 * between big endian and little endian */
	device->state = (union drbd_dev_state) {
		{ .role = R_SECONDARY,
		  .peer = R_UNKNOWN,
		  .conn = C_STANDALONE,
		  .disk = D_DISKLESS,
		  .pdsk = D_UNKNOWN,
		} };
}

void drbd_init_set_defaults(struct drbd_device *device)
{
	/* the memset(,0,) did most of this.
	 * note: only assignments, no allocation in here */

	drbd_set_defaults(device);

	atomic_set(&device->ap_bio_cnt, 0);
	atomic_set(&device->ap_actlog_cnt, 0);
	atomic_set(&device->ap_pending_cnt, 0);
	atomic_set(&device->rs_pending_cnt, 0);
	atomic_set(&device->unacked_cnt, 0);
	atomic_set(&device->local_cnt, 0);
	atomic_set(&device->pp_in_use_by_net, 0);
	atomic_set(&device->rs_sect_in, 0);
	atomic_set(&device->rs_sect_ev, 0);
	atomic_set(&device->ap_in_flight, 0);
	atomic_set(&device->md_io.in_use, 0);

	mutex_init(&device->own_state_mutex);
	device->state_mutex = &device->own_state_mutex;

	spin_lock_init(&device->al_lock);
	spin_lock_init(&device->peer_seq_lock);

	INIT_LIST_HEAD(&device->active_ee);
	INIT_LIST_HEAD(&device->sync_ee);
	INIT_LIST_HEAD(&device->done_ee);
	INIT_LIST_HEAD(&device->read_ee);
	INIT_LIST_HEAD(&device->net_ee);
	INIT_LIST_HEAD(&device->resync_reads);
	INIT_LIST_HEAD(&device->resync_work.list);
	INIT_LIST_HEAD(&device->unplug_work.list);
	INIT_LIST_HEAD(&device->bm_io_work.w.list);
	INIT_LIST_HEAD(&device->pending_master_completion[0]);
	INIT_LIST_HEAD(&device->pending_master_completion[1]);
	INIT_LIST_HEAD(&device->pending_completion[0]);
	INIT_LIST_HEAD(&device->pending_completion[1]);

	device->resync_work.cb  = w_resync_timer;
	device->unplug_work.cb  = w_send_write_hint;
	device->bm_io_work.w.cb = w_bitmap_io;

	init_timer(&device->resync_timer);
	init_timer(&device->md_sync_timer);
	init_timer(&device->start_resync_timer);
	init_timer(&device->request_timer);
	device->resync_timer.function = resync_timer_fn;
	device->resync_timer.data = (unsigned long) device;
	device->md_sync_timer.function = md_sync_timer_fn;
	device->md_sync_timer.data = (unsigned long) device;
	device->start_resync_timer.function = start_resync_timer_fn;
	device->start_resync_timer.data = (unsigned long) device;
	device->request_timer.function = request_timer_fn;
	device->request_timer.data = (unsigned long) device;

	init_waitqueue_head(&device->misc_wait);
	init_waitqueue_head(&device->state_wait);
	init_waitqueue_head(&device->ee_wait);
	init_waitqueue_head(&device->al_wait);
	init_waitqueue_head(&device->seq_wait);

	device->resync_wenr = LC_FREE;
	device->peer_max_bio_size = DRBD_MAX_BIO_SIZE_SAFE;
	device->local_max_bio_size = DRBD_MAX_BIO_SIZE_SAFE;
}

void drbd_device_cleanup(struct drbd_device *device)
{
	int i;
	if (first_peer_device(device)->connection->receiver.t_state != NONE)
		drbd_err(device, "ASSERT FAILED: receiver t_state == %d expected 0.\n",
				first_peer_device(device)->connection->receiver.t_state);

	device->al_writ_cnt  =
	device->bm_writ_cnt  =
	device->read_cnt     =
	device->recv_cnt     =
	device->send_cnt     =
	device->writ_cnt     =
	device->p_size       =
	device->rs_start     =
	device->rs_total     =
	device->rs_failed    = 0;
	device->rs_last_events = 0;
	device->rs_last_sect_ev = 0;
	for (i = 0; i < DRBD_SYNC_MARKS; i++) {
		device->rs_mark_left[i] = 0;
		device->rs_mark_time[i] = 0;
	}
	D_ASSERT(device, first_peer_device(device)->connection->net_conf == NULL);

	drbd_set_my_capacity(device, 0);
	if (device->bitmap) {
		/* maybe never allocated. */
		drbd_bm_resize(device, 0, 1);
		drbd_bm_cleanup(device);
	}

	drbd_backing_dev_free(device, device->ldev);
	device->ldev = NULL;

	clear_bit(AL_SUSPENDED, &device->flags);

	D_ASSERT(device, list_empty(&device->active_ee));
	D_ASSERT(device, list_empty(&device->sync_ee));
	D_ASSERT(device, list_empty(&device->done_ee));
	D_ASSERT(device, list_empty(&device->read_ee));
	D_ASSERT(device, list_empty(&device->net_ee));
	D_ASSERT(device, list_empty(&device->resync_reads));
	D_ASSERT(device, list_empty(&first_peer_device(device)->connection->sender_work.q));
	D_ASSERT(device, list_empty(&device->resync_work.list));
	D_ASSERT(device, list_empty(&device->unplug_work.list));

	drbd_set_defaults(device);
}


static void drbd_destroy_mempools(void)
{
	struct page *page;

	while (drbd_pp_pool) {
		page = drbd_pp_pool;
		drbd_pp_pool = (struct page *)page_private(page);
		__free_page(page);
		drbd_pp_vacant--;
	}

	/* D_ASSERT(device, atomic_read(&drbd_pp_vacant)==0); */

	if (drbd_md_io_bio_set)
		bioset_free(drbd_md_io_bio_set);
	if (drbd_md_io_page_pool)
		mempool_destroy(drbd_md_io_page_pool);
	if (drbd_ee_mempool)
		mempool_destroy(drbd_ee_mempool);
	if (drbd_request_mempool)
		mempool_destroy(drbd_request_mempool);
	if (drbd_ee_cache)
		kmem_cache_destroy(drbd_ee_cache);
	if (drbd_request_cache)
		kmem_cache_destroy(drbd_request_cache);
	if (drbd_bm_ext_cache)
		kmem_cache_destroy(drbd_bm_ext_cache);
	if (drbd_al_ext_cache)
		kmem_cache_destroy(drbd_al_ext_cache);

	drbd_md_io_bio_set   = NULL;
	drbd_md_io_page_pool = NULL;
	drbd_ee_mempool      = NULL;
	drbd_request_mempool = NULL;
	drbd_ee_cache        = NULL;
	drbd_request_cache   = NULL;
	drbd_bm_ext_cache    = NULL;
	drbd_al_ext_cache    = NULL;

	return;
}

static int drbd_create_mempools(void)
{
	struct page *page;
	const int number = (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * minor_count;
	int i;

	/* prepare our caches and mempools */
	drbd_request_mempool = NULL;
	drbd_ee_cache        = NULL;
	drbd_request_cache   = NULL;
	drbd_bm_ext_cache    = NULL;
	drbd_al_ext_cache    = NULL;
	drbd_pp_pool         = NULL;
	drbd_md_io_page_pool = NULL;
	drbd_md_io_bio_set   = NULL;

	/* caches */
	drbd_request_cache = kmem_cache_create(
		"drbd_req", sizeof(struct drbd_request), 0, 0, NULL);
	if (drbd_request_cache == NULL)
		goto Enomem;

	drbd_ee_cache = kmem_cache_create(
		"drbd_ee", sizeof(struct drbd_peer_request), 0, 0, NULL);
	if (drbd_ee_cache == NULL)
		goto Enomem;

	drbd_bm_ext_cache = kmem_cache_create(
		"drbd_bm", sizeof(struct bm_extent), 0, 0, NULL);
	if (drbd_bm_ext_cache == NULL)
		goto Enomem;

	drbd_al_ext_cache = kmem_cache_create(
		"drbd_al", sizeof(struct lc_element), 0, 0, NULL);
	if (drbd_al_ext_cache == NULL)
		goto Enomem;

	/* mempools */
	drbd_md_io_bio_set = bioset_create(DRBD_MIN_POOL_PAGES, 0);
	if (drbd_md_io_bio_set == NULL)
		goto Enomem;

	drbd_md_io_page_pool = mempool_create_page_pool(DRBD_MIN_POOL_PAGES, 0);
	if (drbd_md_io_page_pool == NULL)
		goto Enomem;

	drbd_request_mempool = mempool_create_slab_pool(number,
		drbd_request_cache);
	if (drbd_request_mempool == NULL)
		goto Enomem;

	drbd_ee_mempool = mempool_create_slab_pool(number, drbd_ee_cache);
	if (drbd_ee_mempool == NULL)
		goto Enomem;

	/* drbd's page pool */
	spin_lock_init(&drbd_pp_lock);

	for (i = 0; i < number; i++) {
		page = alloc_page(GFP_HIGHUSER);
		if (!page)
			goto Enomem;
		set_page_private(page, (unsigned long)drbd_pp_pool);
		drbd_pp_pool = page;
	}
	drbd_pp_vacant = number;

	return 0;

Enomem:
	drbd_destroy_mempools(); /* in case we allocated some */
	return -ENOMEM;
}

static void drbd_release_all_peer_reqs(struct drbd_device *device)
{
	int rr;

	rr = drbd_free_peer_reqs(device, &device->active_ee);
	if (rr)
		drbd_err(device, "%d EEs in active list found!\n", rr);

	rr = drbd_free_peer_reqs(device, &device->sync_ee);
	if (rr)
		drbd_err(device, "%d EEs in sync list found!\n", rr);

	rr = drbd_free_peer_reqs(device, &device->read_ee);
	if (rr)
		drbd_err(device, "%d EEs in read list found!\n", rr);

	rr = drbd_free_peer_reqs(device, &device->done_ee);
	if (rr)
		drbd_err(device, "%d EEs in done list found!\n", rr);

	rr = drbd_free_peer_reqs(device, &device->net_ee);
	if (rr)
		drbd_err(device, "%d EEs in net list found!\n", rr);
}

/* caution. no locking. */
void drbd_destroy_device(struct kref *kref)
{
	struct drbd_device *device = container_of(kref, struct drbd_device, kref);
	struct drbd_resource *resource = device->resource;
	struct drbd_peer_device *peer_device, *tmp_peer_device;

	del_timer_sync(&device->request_timer);

	/* paranoia asserts */
	D_ASSERT(device, device->open_cnt == 0);
	/* end paranoia asserts */

	/* cleanup stuff that may have been allocated during
	 * device (re-)configuration or state changes */

	if (device->this_bdev)
		bdput(device->this_bdev);

	drbd_backing_dev_free(device, device->ldev);
	device->ldev = NULL;

	drbd_release_all_peer_reqs(device);

	lc_destroy(device->act_log);
	lc_destroy(device->resync);

	kfree(device->p_uuid);
	/* device->p_uuid = NULL; */

	if (device->bitmap) /* should no longer be there. */
		drbd_bm_cleanup(device);
	__free_page(device->md_io.page);
	put_disk(device->vdisk);
	blk_cleanup_queue(device->rq_queue);
	kfree(device->rs_plan_s);

	/* not for_each_connection(connection, resource):
	 * those may have been cleaned up and disassociated already.
	 */
	for_each_peer_device_safe(peer_device, tmp_peer_device, device) {
		kref_put(&peer_device->connection->kref, drbd_destroy_connection);
		kfree(peer_device);
	}
	memset(device, 0xfd, sizeof(*device));
	kfree(device);
	kref_put(&resource->kref, drbd_destroy_resource);
}

/* One global retry thread, if we need to push back some bio and have it
 * reinserted through our make request function.
 */
static struct retry_worker {
	struct workqueue_struct *wq;
	struct work_struct worker;

	spinlock_t lock;
	struct list_head writes;
} retry;

static void do_retry(struct work_struct *ws)
{
	struct retry_worker *retry = container_of(ws, struct retry_worker, worker);
	LIST_HEAD(writes);
	struct drbd_request *req, *tmp;

	spin_lock_irq(&retry->lock);
	list_splice_init(&retry->writes, &writes);
	spin_unlock_irq(&retry->lock);

	list_for_each_entry_safe(req, tmp, &writes, tl_requests) {
		struct drbd_device *device = req->device;
		struct bio *bio = req->master_bio;
		unsigned long start_jif = req->start_jif;
		bool expected;

		expected =
			expect(atomic_read(&req->completion_ref) == 0) &&
			expect(req->rq_state & RQ_POSTPONED) &&
			expect((req->rq_state & RQ_LOCAL_PENDING) == 0 ||
				(req->rq_state & RQ_LOCAL_ABORTED) != 0);

		if (!expected)
			drbd_err(device, "req=%p completion_ref=%d rq_state=%x\n",
				req, atomic_read(&req->completion_ref),
				req->rq_state);

		/* We still need to put one kref associated with the
		 * "completion_ref" going zero in the code path that queued it
		 * here.  The request object may still be referenced by a
		 * frozen local req->private_bio, in case we force-detached.
		 */
		kref_put(&req->kref, drbd_req_destroy);

		/* A single suspended or otherwise blocking device may stall
		 * all others as well.  Fortunately, this code path is to
		 * recover from a situation that "should not happen":
		 * concurrent writes in multi-primary setup.
		 * In a "normal" lifecycle, this workqueue is supposed to be
		 * destroyed without ever doing anything.
		 * If it turns out to be an issue anyways, we can do per
		 * resource (replication group) or per device (minor) retry
		 * workqueues instead.
		 */

		/* We are not just doing generic_make_request(),
		 * as we want to keep the start_time information. */
		inc_ap_bio(device);
		__drbd_make_request(device, bio, start_jif);
	}
}

/* called via drbd_req_put_completion_ref(),
 * holds resource->req_lock */
void drbd_restart_request(struct drbd_request *req)
{
	unsigned long flags;
	spin_lock_irqsave(&retry.lock, flags);
	list_move_tail(&req->tl_requests, &retry.writes);
	spin_unlock_irqrestore(&retry.lock, flags);

	/* Drop the extra reference that would otherwise
	 * have been dropped by complete_master_bio.
	 * do_retry() needs to grab a new one. */
	dec_ap_bio(req->device);

	queue_work(retry.wq, &retry.worker);
}

void drbd_destroy_resource(struct kref *kref)
{
	struct drbd_resource *resource =
		container_of(kref, struct drbd_resource, kref);

	idr_destroy(&resource->devices);
	free_cpumask_var(resource->cpu_mask);
	kfree(resource->name);
	memset(resource, 0xf2, sizeof(*resource));
	kfree(resource);
}

void drbd_free_resource(struct drbd_resource *resource)
{
	struct drbd_connection *connection, *tmp;

	for_each_connection_safe(connection, tmp, resource) {
		list_del(&connection->connections);
		drbd_debugfs_connection_cleanup(connection);
		kref_put(&connection->kref, drbd_destroy_connection);
	}
	drbd_debugfs_resource_cleanup(resource);
	kref_put(&resource->kref, drbd_destroy_resource);
}

static void drbd_cleanup(void)
{
	unsigned int i;
	struct drbd_device *device;
	struct drbd_resource *resource, *tmp;

	/* first remove proc,
	 * drbdsetup uses it's presence to detect
	 * whether DRBD is loaded.
	 * If we would get stuck in proc removal,
	 * but have netlink already deregistered,
	 * some drbdsetup commands may wait forever
	 * for an answer.
	 */
	if (drbd_proc)
		remove_proc_entry("drbd", NULL);

	if (retry.wq)
		destroy_workqueue(retry.wq);

	drbd_genl_unregister();
	drbd_debugfs_cleanup();

	idr_for_each_entry(&drbd_devices, device, i)
		drbd_delete_device(device);

	/* not _rcu since, no other updater anymore. Genl already unregistered */
	for_each_resource_safe(resource, tmp, &drbd_resources) {
		list_del(&resource->resources);
		drbd_free_resource(resource);
	}

	drbd_destroy_mempools();
	unregister_blkdev(DRBD_MAJOR, "drbd");

	idr_destroy(&drbd_devices);

	pr_info("module cleanup done.\n");
}

/**
 * drbd_congested() - Callback for the flusher thread
 * @congested_data:	User data
 * @bdi_bits:		Bits the BDI flusher thread is currently interested in
 *
 * Returns 1<<WB_async_congested and/or 1<<WB_sync_congested if we are congested.
 */
static int drbd_congested(void *congested_data, int bdi_bits)
{
	struct drbd_device *device = congested_data;
	struct request_queue *q;
	char reason = '-';
	int r = 0;

	if (!may_inc_ap_bio(device)) {
		/* DRBD has frozen IO */
		r = bdi_bits;
		reason = 'd';
		goto out;
	}

	if (test_bit(CALLBACK_PENDING, &first_peer_device(device)->connection->flags)) {
		r |= (1 << WB_async_congested);
		/* Without good local data, we would need to read from remote,
		 * and that would need the worker thread as well, which is
		 * currently blocked waiting for that usermode helper to
		 * finish.
		 */
		if (!get_ldev_if_state(device, D_UP_TO_DATE))
			r |= (1 << WB_sync_congested);
		else
			put_ldev(device);
		r &= bdi_bits;
		reason = 'c';
		goto out;
	}

	if (get_ldev(device)) {
		q = bdev_get_queue(device->ldev->backing_bdev);
		r = bdi_congested(&q->backing_dev_info, bdi_bits);
		put_ldev(device);
		if (r)
			reason = 'b';
	}

	if (bdi_bits & (1 << WB_async_congested) &&
	    test_bit(NET_CONGESTED, &first_peer_device(device)->connection->flags)) {
		r |= (1 << WB_async_congested);
		reason = reason == 'b' ? 'a' : 'n';
	}

out:
	device->congestion_reason = reason;
	return r;
}

static void drbd_init_workqueue(struct drbd_work_queue* wq)
{
	spin_lock_init(&wq->q_lock);
	INIT_LIST_HEAD(&wq->q);
	init_waitqueue_head(&wq->q_wait);
}

struct completion_work {
	struct drbd_work w;
	struct completion done;
};

static int w_complete(struct drbd_work *w, int cancel)
{
	struct completion_work *completion_work =
		container_of(w, struct completion_work, w);

	complete(&completion_work->done);
	return 0;
}

void drbd_flush_workqueue(struct drbd_work_queue *work_queue)
{
	struct completion_work completion_work;

	completion_work.w.cb = w_complete;
	init_completion(&completion_work.done);
	drbd_queue_work(work_queue, &completion_work.w);
	wait_for_completion(&completion_work.done);
}

struct drbd_resource *drbd_find_resource(const char *name)
{
	struct drbd_resource *resource;

	if (!name || !name[0])
		return NULL;

	rcu_read_lock();
	for_each_resource_rcu(resource, &drbd_resources) {
		if (!strcmp(resource->name, name)) {
			kref_get(&resource->kref);
			goto found;
		}
	}
	resource = NULL;
found:
	rcu_read_unlock();
	return resource;
}

struct drbd_connection *conn_get_by_addrs(void *my_addr, int my_addr_len,
				     void *peer_addr, int peer_addr_len)
{
	struct drbd_resource *resource;
	struct drbd_connection *connection;

	rcu_read_lock();
	for_each_resource_rcu(resource, &drbd_resources) {
		for_each_connection_rcu(connection, resource) {
			if (connection->my_addr_len == my_addr_len &&
			    connection->peer_addr_len == peer_addr_len &&
			    !memcmp(&connection->my_addr, my_addr, my_addr_len) &&
			    !memcmp(&connection->peer_addr, peer_addr, peer_addr_len)) {
				kref_get(&connection->kref);
				goto found;
			}
		}
	}
	connection = NULL;
found:
	rcu_read_unlock();
	return connection;
}

static int drbd_alloc_socket(struct drbd_socket *socket)
{
	socket->rbuf = (void *) __get_free_page(GFP_KERNEL);
	if (!socket->rbuf)
		return -ENOMEM;
	socket->sbuf = (void *) __get_free_page(GFP_KERNEL);
	if (!socket->sbuf)
		return -ENOMEM;
	return 0;
}

static void drbd_free_socket(struct drbd_socket *socket)
{
	free_page((unsigned long) socket->sbuf);
	free_page((unsigned long) socket->rbuf);
}

void conn_free_crypto(struct drbd_connection *connection)
{
	drbd_free_sock(connection);

	crypto_free_ahash(connection->csums_tfm);
	crypto_free_ahash(connection->verify_tfm);
	crypto_free_shash(connection->cram_hmac_tfm);
	crypto_free_ahash(connection->integrity_tfm);
	crypto_free_ahash(connection->peer_integrity_tfm);
	kfree(connection->int_dig_in);
	kfree(connection->int_dig_vv);

	connection->csums_tfm = NULL;
	connection->verify_tfm = NULL;
	connection->cram_hmac_tfm = NULL;
	connection->integrity_tfm = NULL;
	connection->peer_integrity_tfm = NULL;
	connection->int_dig_in = NULL;
	connection->int_dig_vv = NULL;
}

int set_resource_options(struct drbd_resource *resource, struct res_opts *res_opts)
{
	struct drbd_connection *connection;
	cpumask_var_t new_cpu_mask;
	int err;

	if (!zalloc_cpumask_var(&new_cpu_mask, GFP_KERNEL))
		return -ENOMEM;

	/* silently ignore cpu mask on UP kernel */
	if (nr_cpu_ids > 1 && res_opts->cpu_mask[0] != 0) {
		err = bitmap_parse(res_opts->cpu_mask, DRBD_CPU_MASK_SIZE,
				   cpumask_bits(new_cpu_mask), nr_cpu_ids);
		if (err == -EOVERFLOW) {
			/* So what. mask it out. */
			cpumask_var_t tmp_cpu_mask;
			if (zalloc_cpumask_var(&tmp_cpu_mask, GFP_KERNEL)) {
				cpumask_setall(tmp_cpu_mask);
				cpumask_and(new_cpu_mask, new_cpu_mask, tmp_cpu_mask);
				drbd_warn(resource, "Overflow in bitmap_parse(%.12s%s), truncating to %u bits\n",
					res_opts->cpu_mask,
					strlen(res_opts->cpu_mask) > 12 ? "..." : "",
					nr_cpu_ids);
				free_cpumask_var(tmp_cpu_mask);
				err = 0;
			}
		}
		if (err) {
			drbd_warn(resource, "bitmap_parse() failed with %d\n", err);
			/* retcode = ERR_CPU_MASK_PARSE; */
			goto fail;
		}
	}
	resource->res_opts = *res_opts;
	if (cpumask_empty(new_cpu_mask))
		drbd_calc_cpu_mask(&new_cpu_mask);
	if (!cpumask_equal(resource->cpu_mask, new_cpu_mask)) {
		cpumask_copy(resource->cpu_mask, new_cpu_mask);
		for_each_connection_rcu(connection, resource) {
			connection->receiver.reset_cpu_mask = 1;
			connection->ack_receiver.reset_cpu_mask = 1;
			connection->worker.reset_cpu_mask = 1;
		}
	}
	err = 0;

fail:
	free_cpumask_var(new_cpu_mask);
	return err;

}

struct drbd_resource *drbd_create_resource(const char *name)
{
	struct drbd_resource *resource;

	resource = kzalloc(sizeof(struct drbd_resource), GFP_KERNEL);
	if (!resource)
		goto fail;
	resource->name = kstrdup(name, GFP_KERNEL);
	if (!resource->name)
		goto fail_free_resource;
	if (!zalloc_cpumask_var(&resource->cpu_mask, GFP_KERNEL))
		goto fail_free_name;
	kref_init(&resource->kref);
	idr_init(&resource->devices);
	INIT_LIST_HEAD(&resource->connections);
	resource->write_ordering = WO_BDEV_FLUSH;
	list_add_tail_rcu(&resource->resources, &drbd_resources);
	mutex_init(&resource->conf_update);
	mutex_init(&resource->adm_mutex);
	spin_lock_init(&resource->req_lock);
	drbd_debugfs_resource_add(resource);
	return resource;

fail_free_name:
	kfree(resource->name);
fail_free_resource:
	kfree(resource);
fail:
	return NULL;
}

/* caller must be under adm_mutex */
struct drbd_connection *conn_create(const char *name, struct res_opts *res_opts)
{
	struct drbd_resource *resource;
	struct drbd_connection *connection;

	connection = kzalloc(sizeof(struct drbd_connection), GFP_KERNEL);
	if (!connection)
		return NULL;

	if (drbd_alloc_socket(&connection->data))
		goto fail;
	if (drbd_alloc_socket(&connection->meta))
		goto fail;

	connection->current_epoch = kzalloc(sizeof(struct drbd_epoch), GFP_KERNEL);
	if (!connection->current_epoch)
		goto fail;

	INIT_LIST_HEAD(&connection->transfer_log);

	INIT_LIST_HEAD(&connection->current_epoch->list);
	connection->epochs = 1;
	spin_lock_init(&connection->epoch_lock);

	connection->send.seen_any_write_yet = false;
	connection->send.current_epoch_nr = 0;
	connection->send.current_epoch_writes = 0;

	resource = drbd_create_resource(name);
	if (!resource)
		goto fail;

	connection->cstate = C_STANDALONE;
	mutex_init(&connection->cstate_mutex);
	init_waitqueue_head(&connection->ping_wait);
	idr_init(&connection->peer_devices);

	drbd_init_workqueue(&connection->sender_work);
	mutex_init(&connection->data.mutex);
	mutex_init(&connection->meta.mutex);

	drbd_thread_init(resource, &connection->receiver, drbd_receiver, "receiver");
	connection->receiver.connection = connection;
	drbd_thread_init(resource, &connection->worker, drbd_worker, "worker");
	connection->worker.connection = connection;
	drbd_thread_init(resource, &connection->ack_receiver, drbd_ack_receiver, "ack_recv");
	connection->ack_receiver.connection = connection;

	kref_init(&connection->kref);

	connection->resource = resource;

	if (set_resource_options(resource, res_opts))
		goto fail_resource;

	kref_get(&resource->kref);
	list_add_tail_rcu(&connection->connections, &resource->connections);
	drbd_debugfs_connection_add(connection);
	return connection;

fail_resource:
	list_del(&resource->resources);
	drbd_free_resource(resource);
fail:
	kfree(connection->current_epoch);
	drbd_free_socket(&connection->meta);
	drbd_free_socket(&connection->data);
	kfree(connection);
	return NULL;
}

void drbd_destroy_connection(struct kref *kref)
{
	struct drbd_connection *connection = container_of(kref, struct drbd_connection, kref);
	struct drbd_resource *resource = connection->resource;

	if (atomic_read(&connection->current_epoch->epoch_size) !=  0)
		drbd_err(connection, "epoch_size:%d\n", atomic_read(&connection->current_epoch->epoch_size));
	kfree(connection->current_epoch);

	idr_destroy(&connection->peer_devices);

	drbd_free_socket(&connection->meta);
	drbd_free_socket(&connection->data);
	kfree(connection->int_dig_in);
	kfree(connection->int_dig_vv);
	memset(connection, 0xfc, sizeof(*connection));
	kfree(connection);
	kref_put(&resource->kref, drbd_destroy_resource);
}

static int init_submitter(struct drbd_device *device)
{
	/* opencoded create_singlethread_workqueue(),
	 * to be able to say "drbd%d", ..., minor */
	device->submit.wq =
		alloc_ordered_workqueue("drbd%u_submit", WQ_MEM_RECLAIM, device->minor);
	if (!device->submit.wq)
		return -ENOMEM;

	INIT_WORK(&device->submit.worker, do_submit);
	INIT_LIST_HEAD(&device->submit.writes);
	return 0;
}

enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor)
{
	struct drbd_resource *resource = adm_ctx->resource;
	struct drbd_connection *connection;
	struct drbd_device *device;
	struct drbd_peer_device *peer_device, *tmp_peer_device;
	struct gendisk *disk;
	struct request_queue *q;
	int id;
	int vnr = adm_ctx->volume;
	enum drbd_ret_code err = ERR_NOMEM;

	device = minor_to_device(minor);
	if (device)
		return ERR_MINOR_OR_VOLUME_EXISTS;

	/* GFP_KERNEL, we are outside of all write-out paths */
	device = kzalloc(sizeof(struct drbd_device), GFP_KERNEL);
	if (!device)
		return ERR_NOMEM;
	kref_init(&device->kref);

	kref_get(&resource->kref);
	device->resource = resource;
	device->minor = minor;
	device->vnr = vnr;

	drbd_init_set_defaults(device);

	q = blk_alloc_queue(GFP_KERNEL);
	if (!q)
		goto out_no_q;
	device->rq_queue = q;
	q->queuedata   = device;

	disk = alloc_disk(1);
	if (!disk)
		goto out_no_disk;
	device->vdisk = disk;

	set_disk_ro(disk, true);

	disk->queue = q;
	disk->major = DRBD_MAJOR;
	disk->first_minor = minor;
	disk->fops = &drbd_ops;
	sprintf(disk->disk_name, "drbd%d", minor);
	disk->private_data = device;

	device->this_bdev = bdget(MKDEV(DRBD_MAJOR, minor));
	/* we have no partitions. we contain only ourselves. */
	device->this_bdev->bd_contains = device->this_bdev;

	q->backing_dev_info.congested_fn = drbd_congested;
	q->backing_dev_info.congested_data = device;

	blk_queue_make_request(q, drbd_make_request);
	blk_queue_write_cache(q, true, true);
	/* Setting the max_hw_sectors to an odd value of 8kibyte here
	   This triggers a max_bio_size message upon first attach or connect */
	blk_queue_max_hw_sectors(q, DRBD_MAX_BIO_SIZE_SAFE >> 8);
	blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
	q->queue_lock = &resource->req_lock;

	device->md_io.page = alloc_page(GFP_KERNEL);
	if (!device->md_io.page)
		goto out_no_io_page;

	if (drbd_bm_init(device))
		goto out_no_bitmap;
	device->read_requests = RB_ROOT;
	device->write_requests = RB_ROOT;

	id = idr_alloc(&drbd_devices, device, minor, minor + 1, GFP_KERNEL);
	if (id < 0) {
		if (id == -ENOSPC)
			err = ERR_MINOR_OR_VOLUME_EXISTS;
		goto out_no_minor_idr;
	}
	kref_get(&device->kref);

	id = idr_alloc(&resource->devices, device, vnr, vnr + 1, GFP_KERNEL);
	if (id < 0) {
		if (id == -ENOSPC)
			err = ERR_MINOR_OR_VOLUME_EXISTS;
		goto out_idr_remove_minor;
	}
	kref_get(&device->kref);

	INIT_LIST_HEAD(&device->peer_devices);
	INIT_LIST_HEAD(&device->pending_bitmap_io);
	for_each_connection(connection, resource) {
		peer_device = kzalloc(sizeof(struct drbd_peer_device), GFP_KERNEL);
		if (!peer_device)
			goto out_idr_remove_from_resource;
		peer_device->connection = connection;
		peer_device->device = device;

		list_add(&peer_device->peer_devices, &device->peer_devices);
		kref_get(&device->kref);

		id = idr_alloc(&connection->peer_devices, peer_device, vnr, vnr + 1, GFP_KERNEL);
		if (id < 0) {
			if (id == -ENOSPC)
				err = ERR_INVALID_REQUEST;
			goto out_idr_remove_from_resource;
		}
		kref_get(&connection->kref);
		INIT_WORK(&peer_device->send_acks_work, drbd_send_acks_wf);
	}

	if (init_submitter(device)) {
		err = ERR_NOMEM;
		goto out_idr_remove_vol;
	}

	add_disk(disk);

	/* inherit the connection state */
	device->state.conn = first_connection(resource)->cstate;
	if (device->state.conn == C_WF_REPORT_PARAMS) {
		for_each_peer_device(peer_device, device)
			drbd_connected(peer_device);
	}
	/* move to create_peer_device() */
	for_each_peer_device(peer_device, device)
		drbd_debugfs_peer_device_add(peer_device);
	drbd_debugfs_device_add(device);
	return NO_ERROR;

out_idr_remove_vol:
	idr_remove(&connection->peer_devices, vnr);
out_idr_remove_from_resource:
	for_each_connection(connection, resource) {
		peer_device = idr_find(&connection->peer_devices, vnr);
		if (peer_device) {
			idr_remove(&connection->peer_devices, vnr);
			kref_put(&connection->kref, drbd_destroy_connection);
		}
	}
	for_each_peer_device_safe(peer_device, tmp_peer_device, device) {
		list_del(&peer_device->peer_devices);
		kfree(peer_device);
	}
	idr_remove(&resource->devices, vnr);
out_idr_remove_minor:
	idr_remove(&drbd_devices, minor);
	synchronize_rcu();
out_no_minor_idr:
	drbd_bm_cleanup(device);
out_no_bitmap:
	__free_page(device->md_io.page);
out_no_io_page:
	put_disk(disk);
out_no_disk:
	blk_cleanup_queue(q);
out_no_q:
	kref_put(&resource->kref, drbd_destroy_resource);
	kfree(device);
	return err;
}

void drbd_delete_device(struct drbd_device *device)
{
	struct drbd_resource *resource = device->resource;
	struct drbd_connection *connection;
	struct drbd_peer_device *peer_device;
	int refs = 3;

	/* move to free_peer_device() */
	for_each_peer_device(peer_device, device)
		drbd_debugfs_peer_device_cleanup(peer_device);
	drbd_debugfs_device_cleanup(device);
	for_each_connection(connection, resource) {
		idr_remove(&connection->peer_devices, device->vnr);
		refs++;
	}
	idr_remove(&resource->devices, device->vnr);
	idr_remove(&drbd_devices, device_to_minor(device));
	del_gendisk(device->vdisk);
	synchronize_rcu();
	kref_sub(&device->kref, refs, drbd_destroy_device);
}

static int __init drbd_init(void)
{
	int err;

	if (minor_count < DRBD_MINOR_COUNT_MIN || minor_count > DRBD_MINOR_COUNT_MAX) {
		pr_err("invalid minor_count (%d)\n", minor_count);
#ifdef MODULE
		return -EINVAL;
#else
		minor_count = DRBD_MINOR_COUNT_DEF;
#endif
	}

	err = register_blkdev(DRBD_MAJOR, "drbd");
	if (err) {
		pr_err("unable to register block device major %d\n",
		       DRBD_MAJOR);
		return err;
	}

	/*
	 * allocate all necessary structs
	 */
	init_waitqueue_head(&drbd_pp_wait);

	drbd_proc = NULL; /* play safe for drbd_cleanup */
	idr_init(&drbd_devices);

	mutex_init(&resources_mutex);
	INIT_LIST_HEAD(&drbd_resources);

	err = drbd_genl_register();
	if (err) {
		pr_err("unable to register generic netlink family\n");
		goto fail;
	}

	err = drbd_create_mempools();
	if (err)
		goto fail;

	err = -ENOMEM;
	drbd_proc = proc_create_data("drbd", S_IFREG | S_IRUGO , NULL, &drbd_proc_fops, NULL);
	if (!drbd_proc)	{
		pr_err("unable to register proc file\n");
		goto fail;
	}

	retry.wq = create_singlethread_workqueue("drbd-reissue");
	if (!retry.wq) {
		pr_err("unable to create retry workqueue\n");
		goto fail;
	}
	INIT_WORK(&retry.worker, do_retry);
	spin_lock_init(&retry.lock);
	INIT_LIST_HEAD(&retry.writes);

	if (drbd_debugfs_init())
		pr_notice("failed to initialize debugfs -- will not be available\n");

	pr_info("initialized. "
	       "Version: " REL_VERSION " (api:%d/proto:%d-%d)\n",
	       API_VERSION, PRO_VERSION_MIN, PRO_VERSION_MAX);
	pr_info("%s\n", drbd_buildtag());
	pr_info("registered as block device major %d\n", DRBD_MAJOR);
	return 0; /* Success! */

fail:
	drbd_cleanup();
	if (err == -ENOMEM)
		pr_err("ran out of memory\n");
	else
		pr_err("initialization failure\n");
	return err;
}

static void drbd_free_one_sock(struct drbd_socket *ds)
{
	struct socket *s;
	mutex_lock(&ds->mutex);
	s = ds->socket;
	ds->socket = NULL;
	mutex_unlock(&ds->mutex);
	if (s) {
		/* so debugfs does not need to mutex_lock() */
		synchronize_rcu();
		kernel_sock_shutdown(s, SHUT_RDWR);
		sock_release(s);
	}
}

void drbd_free_sock(struct drbd_connection *connection)
{
	if (connection->data.socket)
		drbd_free_one_sock(&connection->data);
	if (connection->meta.socket)
		drbd_free_one_sock(&connection->meta);
}

/* meta data management */

void conn_md_sync(struct drbd_connection *connection)
{
	struct drbd_peer_device *peer_device;
	int vnr;

	rcu_read_lock();
	idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
		struct drbd_device *device = peer_device->device;

		kref_get(&device->kref);
		rcu_read_unlock();
		drbd_md_sync(device);
		kref_put(&device->kref, drbd_destroy_device);
		rcu_read_lock();
	}
	rcu_read_unlock();
}

/* aligned 4kByte */
struct meta_data_on_disk {
	u64 la_size_sect;      /* last agreed size. */
	u64 uuid[UI_SIZE];   /* UUIDs. */
	u64 device_uuid;
	u64 reserved_u64_1;
	u32 flags;             /* MDF */
	u32 magic;
	u32 md_size_sect;
	u32 al_offset;         /* offset to this block */
	u32 al_nr_extents;     /* important for restoring the AL (userspace) */
	      /* `-- act_log->nr_elements <-- ldev->dc.al_extents */
	u32 bm_offset;         /* offset to the bitmap, from here */
	u32 bm_bytes_per_bit;  /* BM_BLOCK_SIZE */
	u32 la_peer_max_bio_size;   /* last peer max_bio_size */

	/* see al_tr_number_to_on_disk_sector() */
	u32 al_stripes;
	u32 al_stripe_size_4k;

	u8 reserved_u8[4096 - (7*8 + 10*4)];
} __packed;



void drbd_md_write(struct drbd_device *device, void *b)
{
	struct meta_data_on_disk *buffer = b;
	sector_t sector;
	int i;

	memset(buffer, 0, sizeof(*buffer));

	buffer->la_size_sect = cpu_to_be64(drbd_get_capacity(device->this_bdev));
	for (i = UI_CURRENT; i < UI_SIZE; i++)
		buffer->uuid[i] = cpu_to_be64(device->ldev->md.uuid[i]);
	buffer->flags = cpu_to_be32(device->ldev->md.flags);
	buffer->magic = cpu_to_be32(DRBD_MD_MAGIC_84_UNCLEAN);

	buffer->md_size_sect  = cpu_to_be32(device->ldev->md.md_size_sect);
	buffer->al_offset     = cpu_to_be32(device->ldev->md.al_offset);
	buffer->al_nr_extents = cpu_to_be32(device->act_log->nr_elements);
	buffer->bm_bytes_per_bit = cpu_to_be32(BM_BLOCK_SIZE);
	buffer->device_uuid = cpu_to_be64(device->ldev->md.device_uuid);

	buffer->bm_offset = cpu_to_be32(device->ldev->md.bm_offset);
	buffer->la_peer_max_bio_size = cpu_to_be32(device->peer_max_bio_size);

	buffer->al_stripes = cpu_to_be32(device->ldev->md.al_stripes);
	buffer->al_stripe_size_4k = cpu_to_be32(device->ldev->md.al_stripe_size_4k);

	D_ASSERT(device, drbd_md_ss(device->ldev) == device->ldev->md.md_offset);
	sector = device->ldev->md.md_offset;

	if (drbd_md_sync_page_io(device, device->ldev, sector, REQ_OP_WRITE)) {
		/* this was a try anyways ... */
		drbd_err(device, "meta data update failed!\n");
		drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
	}
}

/**
 * drbd_md_sync() - Writes the meta data super block if the MD_DIRTY flag bit is set
 * @device:	DRBD device.
 */
void drbd_md_sync(struct drbd_device *device)
{
	struct meta_data_on_disk *buffer;

	/* Don't accidentally change the DRBD meta data layout. */
	BUILD_BUG_ON(UI_SIZE != 4);
	BUILD_BUG_ON(sizeof(struct meta_data_on_disk) != 4096);

	del_timer(&device->md_sync_timer);
	/* timer may be rearmed by drbd_md_mark_dirty() now. */
	if (!test_and_clear_bit(MD_DIRTY, &device->flags))
		return;

	/* We use here D_FAILED and not D_ATTACHING because we try to write
	 * metadata even if we detach due to a disk failure! */
	if (!get_ldev_if_state(device, D_FAILED))
		return;

	buffer = drbd_md_get_buffer(device, __func__);
	if (!buffer)
		goto out;

	drbd_md_write(device, buffer);

	/* Update device->ldev->md.la_size_sect,
	 * since we updated it on metadata. */
	device->ldev->md.la_size_sect = drbd_get_capacity(device->this_bdev);

	drbd_md_put_buffer(device);
out:
	put_ldev(device);
}

static int check_activity_log_stripe_size(struct drbd_device *device,
		struct meta_data_on_disk *on_disk,
		struct drbd_md *in_core)
{
	u32 al_stripes = be32_to_cpu(on_disk->al_stripes);
	u32 al_stripe_size_4k = be32_to_cpu(on_disk->al_stripe_size_4k);
	u64 al_size_4k;

	/* both not set: default to old fixed size activity log */
	if (al_stripes == 0 && al_stripe_size_4k == 0) {
		al_stripes = 1;
		al_stripe_size_4k = MD_32kB_SECT/8;
	}

	/* some paranoia plausibility checks */

	/* we need both values to be set */
	if (al_stripes == 0 || al_stripe_size_4k == 0)
		goto err;

	al_size_4k = (u64)al_stripes * al_stripe_size_4k;

	/* Upper limit of activity log area, to avoid potential overflow
	 * problems in al_tr_number_to_on_disk_sector(). As right now, more
	 * than 72 * 4k blocks total only increases the amount of history,
	 * limiting this arbitrarily to 16 GB is not a real limitation ;-)  */
	if (al_size_4k > (16 * 1024 * 1024/4))
		goto err;

	/* Lower limit: we need at least 8 transaction slots (32kB)
	 * to not break existing setups */
	if (al_size_4k < MD_32kB_SECT/8)
		goto err;

	in_core->al_stripe_size_4k = al_stripe_size_4k;
	in_core->al_stripes = al_stripes;
	in_core->al_size_4k = al_size_4k;

	return 0;
err:
	drbd_err(device, "invalid activity log striping: al_stripes=%u, al_stripe_size_4k=%u\n",
			al_stripes, al_stripe_size_4k);
	return -EINVAL;
}

static int check_offsets_and_sizes(struct drbd_device *device, struct drbd_backing_dev *bdev)
{
	sector_t capacity = drbd_get_capacity(bdev->md_bdev);
	struct drbd_md *in_core = &bdev->md;
	s32 on_disk_al_sect;
	s32 on_disk_bm_sect;

	/* The on-disk size of the activity log, calculated from offsets, and
	 * the size of the activity log calculated from the stripe settings,
	 * should match.
	 * Though we could relax this a bit: it is ok, if the striped activity log
	 * fits in the available on-disk activity log size.
	 * Right now, that would break how resize is implemented.
	 * TODO: make drbd_determine_dev_size() (and the drbdmeta tool) aware
	 * of possible unused padding space in the on disk layout. */
	if (in_core->al_offset < 0) {
		if (in_core->bm_offset > in_core->al_offset)
			goto err;
		on_disk_al_sect = -in_core->al_offset;
		on_disk_bm_sect = in_core->al_offset - in_core->bm_offset;
	} else {
		if (in_core->al_offset != MD_4kB_SECT)
			goto err;
		if (in_core->bm_offset < in_core->al_offset + in_core->al_size_4k * MD_4kB_SECT)
			goto err;

		on_disk_al_sect = in_core->bm_offset - MD_4kB_SECT;
		on_disk_bm_sect = in_core->md_size_sect - in_core->bm_offset;
	}

	/* old fixed size meta data is exactly that: fixed. */
	if (in_core->meta_dev_idx >= 0) {
		if (in_core->md_size_sect != MD_128MB_SECT
		||  in_core->al_offset != MD_4kB_SECT
		||  in_core->bm_offset != MD_4kB_SECT + MD_32kB_SECT
		||  in_core->al_stripes != 1
		||  in_core->al_stripe_size_4k != MD_32kB_SECT/8)
			goto err;
	}

	if (capacity < in_core->md_size_sect)
		goto err;
	if (capacity - in_core->md_size_sect < drbd_md_first_sector(bdev))
		goto err;

	/* should be aligned, and at least 32k */
	if ((on_disk_al_sect & 7) || (on_disk_al_sect < MD_32kB_SECT))
		goto err;

	/* should fit (for now: exactly) into the available on-disk space;
	 * overflow prevention is in check_activity_log_stripe_size() above. */
	if (on_disk_al_sect != in_core->al_size_4k * MD_4kB_SECT)
		goto err;

	/* again, should be aligned */
	if (in_core->bm_offset & 7)
		goto err;

	/* FIXME check for device grow with flex external meta data? */

	/* can the available bitmap space cover the last agreed device size? */
	if (on_disk_bm_sect < (in_core->la_size_sect+7)/MD_4kB_SECT/8/512)
		goto err;

	return 0;

err:
	drbd_err(device, "meta data offsets don't make sense: idx=%d "
			"al_s=%u, al_sz4k=%u, al_offset=%d, bm_offset=%d, "
			"md_size_sect=%u, la_size=%llu, md_capacity=%llu\n",
			in_core->meta_dev_idx,
			in_core->al_stripes, in_core->al_stripe_size_4k,
			in_core->al_offset, in_core->bm_offset, in_core->md_size_sect,
			(unsigned long long)in_core->la_size_sect,
			(unsigned long long)capacity);

	return -EINVAL;
}


/**
 * drbd_md_read() - Reads in the meta data super block
 * @device:	DRBD device.
 * @bdev:	Device from which the meta data should be read in.
 *
 * Return NO_ERROR on success, and an enum drbd_ret_code in case
 * something goes wrong.
 *
 * Called exactly once during drbd_adm_attach(), while still being D_DISKLESS,
 * even before @bdev is assigned to @device->ldev.
 */
int drbd_md_read(struct drbd_device *device, struct drbd_backing_dev *bdev)
{
	struct meta_data_on_disk *buffer;
	u32 magic, flags;
	int i, rv = NO_ERROR;

	if (device->state.disk != D_DISKLESS)
		return ERR_DISK_CONFIGURED;

	buffer = drbd_md_get_buffer(device, __func__);
	if (!buffer)
		return ERR_NOMEM;

	/* First, figure out where our meta data superblock is located,
	 * and read it. */
	bdev->md.meta_dev_idx = bdev->disk_conf->meta_dev_idx;
	bdev->md.md_offset = drbd_md_ss(bdev);
	/* Even for (flexible or indexed) external meta data,
	 * initially restrict us to the 4k superblock for now.
	 * Affects the paranoia out-of-range access check in drbd_md_sync_page_io(). */
	bdev->md.md_size_sect = 8;

	if (drbd_md_sync_page_io(device, bdev, bdev->md.md_offset,
				 REQ_OP_READ)) {
		/* NOTE: can't do normal error processing here as this is
		   called BEFORE disk is attached */
		drbd_err(device, "Error while reading metadata.\n");
		rv = ERR_IO_MD_DISK;
		goto err;
	}

	magic = be32_to_cpu(buffer->magic);
	flags = be32_to_cpu(buffer->flags);
	if (magic == DRBD_MD_MAGIC_84_UNCLEAN ||
	    (magic == DRBD_MD_MAGIC_08 && !(flags & MDF_AL_CLEAN))) {
			/* btw: that's Activity Log clean, not "all" clean. */
		drbd_err(device, "Found unclean meta data. Did you \"drbdadm apply-al\"?\n");
		rv = ERR_MD_UNCLEAN;
		goto err;
	}

	rv = ERR_MD_INVALID;
	if (magic != DRBD_MD_MAGIC_08) {
		if (magic == DRBD_MD_MAGIC_07)
			drbd_err(device, "Found old (0.7) meta data magic. Did you \"drbdadm create-md\"?\n");
		else
			drbd_err(device, "Meta data magic not found. Did you \"drbdadm create-md\"?\n");
		goto err;
	}

	if (be32_to_cpu(buffer->bm_bytes_per_bit) != BM_BLOCK_SIZE) {
		drbd_err(device, "unexpected bm_bytes_per_bit: %u (expected %u)\n",
		    be32_to_cpu(buffer->bm_bytes_per_bit), BM_BLOCK_SIZE);
		goto err;
	}


	/* convert to in_core endian */
	bdev->md.la_size_sect = be64_to_cpu(buffer->la_size_sect);
	for (i = UI_CURRENT; i < UI_SIZE; i++)
		bdev->md.uuid[i] = be64_to_cpu(buffer->uuid[i]);
	bdev->md.flags = be32_to_cpu(buffer->flags);
	bdev->md.device_uuid = be64_to_cpu(buffer->device_uuid);

	bdev->md.md_size_sect = be32_to_cpu(buffer->md_size_sect);
	bdev->md.al_offset = be32_to_cpu(buffer->al_offset);
	bdev->md.bm_offset = be32_to_cpu(buffer->bm_offset);

	if (check_activity_log_stripe_size(device, buffer, &bdev->md))
		goto err;
	if (check_offsets_and_sizes(device, bdev))
		goto err;

	if (be32_to_cpu(buffer->bm_offset) != bdev->md.bm_offset) {
		drbd_err(device, "unexpected bm_offset: %d (expected %d)\n",
		    be32_to_cpu(buffer->bm_offset), bdev->md.bm_offset);
		goto err;
	}
	if (be32_to_cpu(buffer->md_size_sect) != bdev->md.md_size_sect) {
		drbd_err(device, "unexpected md_size: %u (expected %u)\n",
		    be32_to_cpu(buffer->md_size_sect), bdev->md.md_size_sect);
		goto err;
	}

	rv = NO_ERROR;

	spin_lock_irq(&device->resource->req_lock);
	if (device->state.conn < C_CONNECTED) {
		unsigned int peer;
		peer = be32_to_cpu(buffer->la_peer_max_bio_size);
		peer = max(peer, DRBD_MAX_BIO_SIZE_SAFE);
		device->peer_max_bio_size = peer;
	}
	spin_unlock_irq(&device->resource->req_lock);

 err:
	drbd_md_put_buffer(device);

	return rv;
}

/**
 * drbd_md_mark_dirty() - Mark meta data super block as dirty
 * @device:	DRBD device.
 *
 * Call this function if you change anything that should be written to
 * the meta-data super block. This function sets MD_DIRTY, and starts a
 * timer that ensures that within five seconds you have to call drbd_md_sync().
 */
#ifdef DEBUG
void drbd_md_mark_dirty_(struct drbd_device *device, unsigned int line, const char *func)
{
	if (!test_and_set_bit(MD_DIRTY, &device->flags)) {
		mod_timer(&device->md_sync_timer, jiffies + HZ);
		device->last_md_mark_dirty.line = line;
		device->last_md_mark_dirty.func = func;
	}
}
#else
void drbd_md_mark_dirty(struct drbd_device *device)
{
	if (!test_and_set_bit(MD_DIRTY, &device->flags))
		mod_timer(&device->md_sync_timer, jiffies + 5*HZ);
}
#endif

void drbd_uuid_move_history(struct drbd_device *device) __must_hold(local)
{
	int i;

	for (i = UI_HISTORY_START; i < UI_HISTORY_END; i++)
		device->ldev->md.uuid[i+1] = device->ldev->md.uuid[i];
}

void __drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local)
{
	if (idx == UI_CURRENT) {
		if (device->state.role == R_PRIMARY)
			val |= 1;
		else
			val &= ~((u64)1);

		drbd_set_ed_uuid(device, val);
	}

	device->ldev->md.uuid[idx] = val;
	drbd_md_mark_dirty(device);
}

void _drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local)
{
	unsigned long flags;
	spin_lock_irqsave(&device->ldev->md.uuid_lock, flags);
	__drbd_uuid_set(device, idx, val);
	spin_unlock_irqrestore(&device->ldev->md.uuid_lock, flags);
}

void drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local)
{
	unsigned long flags;
	spin_lock_irqsave(&device->ldev->md.uuid_lock, flags);
	if (device->ldev->md.uuid[idx]) {
		drbd_uuid_move_history(device);
		device->ldev->md.uuid[UI_HISTORY_START] = device->ldev->md.uuid[idx];
	}
	__drbd_uuid_set(device, idx, val);
	spin_unlock_irqrestore(&device->ldev->md.uuid_lock, flags);
}

/**
 * drbd_uuid_new_current() - Creates a new current UUID
 * @device:	DRBD device.
 *
 * Creates a new current UUID, and rotates the old current UUID into
 * the bitmap slot. Causes an incremental resync upon next connect.
 */
void drbd_uuid_new_current(struct drbd_device *device) __must_hold(local)
{
	u64 val;
	unsigned long long bm_uuid;

	get_random_bytes(&val, sizeof(u64));

	spin_lock_irq(&device->ldev->md.uuid_lock);
	bm_uuid = device->ldev->md.uuid[UI_BITMAP];

	if (bm_uuid)
		drbd_warn(device, "bm UUID was already set: %llX\n", bm_uuid);

	device->ldev->md.uuid[UI_BITMAP] = device->ldev->md.uuid[UI_CURRENT];
	__drbd_uuid_set(device, UI_CURRENT, val);
	spin_unlock_irq(&device->ldev->md.uuid_lock);

	drbd_print_uuids(device, "new current UUID");
	/* get it to stable storage _now_ */
	drbd_md_sync(device);
}

void drbd_uuid_set_bm(struct drbd_device *device, u64 val) __must_hold(local)
{
	unsigned long flags;
	if (device->ldev->md.uuid[UI_BITMAP] == 0 && val == 0)
		return;

	spin_lock_irqsave(&device->ldev->md.uuid_lock, flags);
	if (val == 0) {
		drbd_uuid_move_history(device);
		device->ldev->md.uuid[UI_HISTORY_START] = device->ldev->md.uuid[UI_BITMAP];
		device->ldev->md.uuid[UI_BITMAP] = 0;
	} else {
		unsigned long long bm_uuid = device->ldev->md.uuid[UI_BITMAP];
		if (bm_uuid)
			drbd_warn(device, "bm UUID was already set: %llX\n", bm_uuid);

		device->ldev->md.uuid[UI_BITMAP] = val & ~((u64)1);
	}
	spin_unlock_irqrestore(&device->ldev->md.uuid_lock, flags);

	drbd_md_mark_dirty(device);
}

/**
 * drbd_bmio_set_n_write() - io_fn for drbd_queue_bitmap_io() or drbd_bitmap_io()
 * @device:	DRBD device.
 *
 * Sets all bits in the bitmap and writes the whole bitmap to stable storage.
 */
int drbd_bmio_set_n_write(struct drbd_device *device) __must_hold(local)
{
	int rv = -EIO;

	drbd_md_set_flag(device, MDF_FULL_SYNC);
	drbd_md_sync(device);
	drbd_bm_set_all(device);

	rv = drbd_bm_write(device);

	if (!rv) {
		drbd_md_clear_flag(device, MDF_FULL_SYNC);
		drbd_md_sync(device);
	}

	return rv;
}

/**
 * drbd_bmio_clear_n_write() - io_fn for drbd_queue_bitmap_io() or drbd_bitmap_io()
 * @device:	DRBD device.
 *
 * Clears all bits in the bitmap and writes the whole bitmap to stable storage.
 */
int drbd_bmio_clear_n_write(struct drbd_device *device) __must_hold(local)
{
	drbd_resume_al(device);
	drbd_bm_clear_all(device);
	return drbd_bm_write(device);
}

static int w_bitmap_io(struct drbd_work *w, int unused)
{
	struct drbd_device *device =
		container_of(w, struct drbd_device, bm_io_work.w);
	struct bm_io_work *work = &device->bm_io_work;
	int rv = -EIO;

	if (work->flags != BM_LOCKED_CHANGE_ALLOWED) {
		int cnt = atomic_read(&device->ap_bio_cnt);
		if (cnt)
			drbd_err(device, "FIXME: ap_bio_cnt %d, expected 0; queued for '%s'\n",
					cnt, work->why);
	}

	if (get_ldev(device)) {
		drbd_bm_lock(device, work->why, work->flags);
		rv = work->io_fn(device);
		drbd_bm_unlock(device);
		put_ldev(device);
	}

	clear_bit_unlock(BITMAP_IO, &device->flags);
	wake_up(&device->misc_wait);

	if (work->done)
		work->done(device, rv);

	clear_bit(BITMAP_IO_QUEUED, &device->flags);
	work->why = NULL;
	work->flags = 0;

	return 0;
}

/**
 * drbd_queue_bitmap_io() - Queues an IO operation on the whole bitmap
 * @device:	DRBD device.
 * @io_fn:	IO callback to be called when bitmap IO is possible
 * @done:	callback to be called after the bitmap IO was performed
 * @why:	Descriptive text of the reason for doing the IO
 *
 * While IO on the bitmap happens we freeze application IO thus we ensure
 * that drbd_set_out_of_sync() can not be called. This function MAY ONLY be
 * called from worker context. It MUST NOT be used while a previous such
 * work is still pending!
 *
 * Its worker function encloses the call of io_fn() by get_ldev() and
 * put_ldev().
 */
void drbd_queue_bitmap_io(struct drbd_device *device,
			  int (*io_fn)(struct drbd_device *),
			  void (*done)(struct drbd_device *, int),
			  char *why, enum bm_flag flags)
{
	D_ASSERT(device, current == first_peer_device(device)->connection->worker.task);

	D_ASSERT(device, !test_bit(BITMAP_IO_QUEUED, &device->flags));
	D_ASSERT(device, !test_bit(BITMAP_IO, &device->flags));
	D_ASSERT(device, list_empty(&device->bm_io_work.w.list));
	if (device->bm_io_work.why)
		drbd_err(device, "FIXME going to queue '%s' but '%s' still pending?\n",
			why, device->bm_io_work.why);

	device->bm_io_work.io_fn = io_fn;
	device->bm_io_work.done = done;
	device->bm_io_work.why = why;
	device->bm_io_work.flags = flags;

	spin_lock_irq(&device->resource->req_lock);
	set_bit(BITMAP_IO, &device->flags);
	/* don't wait for pending application IO if the caller indicates that
	 * application IO does not conflict anyways. */
	if (flags == BM_LOCKED_CHANGE_ALLOWED || atomic_read(&device->ap_bio_cnt) == 0) {
		if (!test_and_set_bit(BITMAP_IO_QUEUED, &device->flags))
			drbd_queue_work(&first_peer_device(device)->connection->sender_work,
					&device->bm_io_work.w);
	}
	spin_unlock_irq(&device->resource->req_lock);
}

/**
 * drbd_bitmap_io() -  Does an IO operation on the whole bitmap
 * @device:	DRBD device.
 * @io_fn:	IO callback to be called when bitmap IO is possible
 * @why:	Descriptive text of the reason for doing the IO
 *
 * freezes application IO while that the actual IO operations runs. This
 * functions MAY NOT be called from worker context.
 */
int drbd_bitmap_io(struct drbd_device *device, int (*io_fn)(struct drbd_device *),
		char *why, enum bm_flag flags)
{
	/* Only suspend io, if some operation is supposed to be locked out */
	const bool do_suspend_io = flags & (BM_DONT_CLEAR|BM_DONT_SET|BM_DONT_TEST);
	int rv;

	D_ASSERT(device, current != first_peer_device(device)->connection->worker.task);

	if (do_suspend_io)
		drbd_suspend_io(device);

	drbd_bm_lock(device, why, flags);
	rv = io_fn(device);
	drbd_bm_unlock(device);

	if (do_suspend_io)
		drbd_resume_io(device);

	return rv;
}

void drbd_md_set_flag(struct drbd_device *device, int flag) __must_hold(local)
{
	if ((device->ldev->md.flags & flag) != flag) {
		drbd_md_mark_dirty(device);
		device->ldev->md.flags |= flag;
	}
}

void drbd_md_clear_flag(struct drbd_device *device, int flag) __must_hold(local)
{
	if ((device->ldev->md.flags & flag) != 0) {
		drbd_md_mark_dirty(device);
		device->ldev->md.flags &= ~flag;
	}
}
int drbd_md_test_flag(struct drbd_backing_dev *bdev, int flag)
{
	return (bdev->md.flags & flag) != 0;
}

static void md_sync_timer_fn(unsigned long data)
{
	struct drbd_device *device = (struct drbd_device *) data;
	drbd_device_post_work(device, MD_SYNC);
}

const char *cmdname(enum drbd_packet cmd)
{
	/* THINK may need to become several global tables
	 * when we want to support more than
	 * one PRO_VERSION */
	static const char *cmdnames[] = {
		[P_DATA]	        = "Data",
		[P_WSAME]	        = "WriteSame",
		[P_TRIM]	        = "Trim",
		[P_DATA_REPLY]	        = "DataReply",
		[P_RS_DATA_REPLY]	= "RSDataReply",
		[P_BARRIER]	        = "Barrier",
		[P_BITMAP]	        = "ReportBitMap",
		[P_BECOME_SYNC_TARGET]  = "BecomeSyncTarget",
		[P_BECOME_SYNC_SOURCE]  = "BecomeSyncSource",
		[P_UNPLUG_REMOTE]	= "UnplugRemote",
		[P_DATA_REQUEST]	= "DataRequest",
		[P_RS_DATA_REQUEST]     = "RSDataRequest",
		[P_SYNC_PARAM]	        = "SyncParam",
		[P_SYNC_PARAM89]	= "SyncParam89",
		[P_PROTOCOL]            = "ReportProtocol",
		[P_UUIDS]	        = "ReportUUIDs",
		[P_SIZES]	        = "ReportSizes",
		[P_STATE]	        = "ReportState",
		[P_SYNC_UUID]           = "ReportSyncUUID",
		[P_AUTH_CHALLENGE]      = "AuthChallenge",
		[P_AUTH_RESPONSE]	= "AuthResponse",
		[P_PING]		= "Ping",
		[P_PING_ACK]	        = "PingAck",
		[P_RECV_ACK]	        = "RecvAck",
		[P_WRITE_ACK]	        = "WriteAck",
		[P_RS_WRITE_ACK]	= "RSWriteAck",
		[P_SUPERSEDED]          = "Superseded",
		[P_NEG_ACK]	        = "NegAck",
		[P_NEG_DREPLY]	        = "NegDReply",
		[P_NEG_RS_DREPLY]	= "NegRSDReply",
		[P_BARRIER_ACK]	        = "BarrierAck",
		[P_STATE_CHG_REQ]       = "StateChgRequest",
		[P_STATE_CHG_REPLY]     = "StateChgReply",
		[P_OV_REQUEST]          = "OVRequest",
		[P_OV_REPLY]            = "OVReply",
		[P_OV_RESULT]           = "OVResult",
		[P_CSUM_RS_REQUEST]     = "CsumRSRequest",
		[P_RS_IS_IN_SYNC]	= "CsumRSIsInSync",
		[P_COMPRESSED_BITMAP]   = "CBitmap",
		[P_DELAY_PROBE]         = "DelayProbe",
		[P_OUT_OF_SYNC]		= "OutOfSync",
		[P_RETRY_WRITE]		= "RetryWrite",
		[P_RS_CANCEL]		= "RSCancel",
		[P_CONN_ST_CHG_REQ]	= "conn_st_chg_req",
		[P_CONN_ST_CHG_REPLY]	= "conn_st_chg_reply",
		[P_RETRY_WRITE]		= "retry_write",
		[P_PROTOCOL_UPDATE]	= "protocol_update",
		[P_RS_THIN_REQ]         = "rs_thin_req",
		[P_RS_DEALLOCATED]      = "rs_deallocated",

		/* enum drbd_packet, but not commands - obsoleted flags:
		 *	P_MAY_IGNORE
		 *	P_MAX_OPT_CMD
		 */
	};

	/* too big for the array: 0xfffX */
	if (cmd == P_INITIAL_META)
		return "InitialMeta";
	if (cmd == P_INITIAL_DATA)
		return "InitialData";
	if (cmd == P_CONNECTION_FEATURES)
		return "ConnectionFeatures";
	if (cmd >= ARRAY_SIZE(cmdnames))
		return "Unknown";
	return cmdnames[cmd];
}

/**
 * drbd_wait_misc  -  wait for a request to make progress
 * @device:	device associated with the request
 * @i:		the struct drbd_interval embedded in struct drbd_request or
 *		struct drbd_peer_request
 */
int drbd_wait_misc(struct drbd_device *device, struct drbd_interval *i)
{
	struct net_conf *nc;
	DEFINE_WAIT(wait);
	long timeout;

	rcu_read_lock();
	nc = rcu_dereference(first_peer_device(device)->connection->net_conf);
	if (!nc) {
		rcu_read_unlock();
		return -ETIMEDOUT;
	}
	timeout = nc->ko_count ? nc->timeout * HZ / 10 * nc->ko_count : MAX_SCHEDULE_TIMEOUT;
	rcu_read_unlock();

	/* Indicate to wake up device->misc_wait on progress.  */
	i->waiting = true;
	prepare_to_wait(&device->misc_wait, &wait, TASK_INTERRUPTIBLE);
	spin_unlock_irq(&device->resource->req_lock);
	timeout = schedule_timeout(timeout);
	finish_wait(&device->misc_wait, &wait);
	spin_lock_irq(&device->resource->req_lock);
	if (!timeout || device->state.conn < C_CONNECTED)
		return -ETIMEDOUT;
	if (signal_pending(current))
		return -ERESTARTSYS;
	return 0;
}

void lock_all_resources(void)
{
	struct drbd_resource *resource;
	int __maybe_unused i = 0;

	mutex_lock(&resources_mutex);
	local_irq_disable();
	for_each_resource(resource, &drbd_resources)
		spin_lock_nested(&resource->req_lock, i++);
}

void unlock_all_resources(void)
{
	struct drbd_resource *resource;

	for_each_resource(resource, &drbd_resources)
		spin_unlock(&resource->req_lock);
	local_irq_enable();
	mutex_unlock(&resources_mutex);
}

#ifdef CONFIG_DRBD_FAULT_INJECTION
/* Fault insertion support including random number generator shamelessly
 * stolen from kernel/rcutorture.c */
struct fault_random_state {
	unsigned long state;
	unsigned long count;
};

#define FAULT_RANDOM_MULT 39916801  /* prime */
#define FAULT_RANDOM_ADD	479001701 /* prime */
#define FAULT_RANDOM_REFRESH 10000

/*
 * Crude but fast random-number generator.  Uses a linear congruential
 * generator, with occasional help from get_random_bytes().
 */
static unsigned long
_drbd_fault_random(struct fault_random_state *rsp)
{
	long refresh;

	if (!rsp->count--) {
		get_random_bytes(&refresh, sizeof(refresh));
		rsp->state += refresh;
		rsp->count = FAULT_RANDOM_REFRESH;
	}
	rsp->state = rsp->state * FAULT_RANDOM_MULT + FAULT_RANDOM_ADD;
	return swahw32(rsp->state);
}

static char *
_drbd_fault_str(unsigned int type) {
	static char *_faults[] = {
		[DRBD_FAULT_MD_WR] = "Meta-data write",
		[DRBD_FAULT_MD_RD] = "Meta-data read",
		[DRBD_FAULT_RS_WR] = "Resync write",
		[DRBD_FAULT_RS_RD] = "Resync read",
		[DRBD_FAULT_DT_WR] = "Data write",
		[DRBD_FAULT_DT_RD] = "Data read",
		[DRBD_FAULT_DT_RA] = "Data read ahead",
		[DRBD_FAULT_BM_ALLOC] = "BM allocation",
		[DRBD_FAULT_AL_EE] = "EE allocation",
		[DRBD_FAULT_RECEIVE] = "receive data corruption",
	};

	return (type < DRBD_FAULT_MAX) ? _faults[type] : "**Unknown**";
}

unsigned int
_drbd_insert_fault(struct drbd_device *device, unsigned int type)
{
	static struct fault_random_state rrs = {0, 0};

	unsigned int ret = (
		(fault_devs == 0 ||
			((1 << device_to_minor(device)) & fault_devs) != 0) &&
		(((_drbd_fault_random(&rrs) % 100) + 1) <= fault_rate));

	if (ret) {
		fault_count++;

		if (__ratelimit(&drbd_ratelimit_state))
			drbd_warn(device, "***Simulating %s failure\n",
				_drbd_fault_str(type));
	}

	return ret;
}
#endif

const char *drbd_buildtag(void)
{
	/* DRBD built from external sources has here a reference to the
	   git hash of the source code. */

	static char buildtag[38] = "\0uilt-in";

	if (buildtag[0] == 0) {
#ifdef MODULE
		sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
#else
		buildtag[0] = 'b';
#endif
	}

	return buildtag;
}

module_init(drbd_init)
module_exit(drbd_cleanup)

EXPORT_SYMBOL(drbd_conn_str);
EXPORT_SYMBOL(drbd_role_str);
EXPORT_SYMBOL(drbd_disk_str);
EXPORT_SYMBOL(drbd_set_st_err_str);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-13 07:12:43 -0500