aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/scsi/iscsi_tcp.c
blob: 10bcf42cb65c0a0eaf021b4052a068019c9658d2 (plain) (tree)
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
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
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


















































                                                                         
                          














































































                                                                                

                                                                
 

                                                             

































































































































































































































































































                                                                                

                                                      


































































































































                                                                            
                                           






















                                                                            





                                                                            


                                   
                                                          
























                                                                               
























                                                                             
                                              




















                                                                          
                                                                          



                                                                

















                                                                          
                                          
































                                                                              
                                                                            





                                                                               


























                                                                                




                                                        



                                                                      
                                                                           









                                                                               
                                                  




                                                  

























































































































                                                                            








                                                                     



                                                      
                               












                                                                               

                                                                              




























































































                                                                               


                                                                   























                                                                         




                                                                  







                                                                           

                                  



















                                                                    







                                                               
                                          































                                                               
                                                










                                                                      
                                     

                                                                














                                                                      



















                                                                           
                                        



































































                                                                                


                                               

























































































































































                                                                                
                                                                 











































































































                                                                              

                                                      












































                                                                                

                                                        






















































































































                                                                                

                                                                 



























                                                                         




                                                                






























                                                                              

                                                                            











                                                                           

                                                                            













































































                                                                              


                                                               















































































































































































































































































































                                                                                


                                                                 
























































































































































































































































                                                                                








                                                                      















































































































































































































































































































































































































































































                                                                               
                                                
                                                                  


                                              






















































                                                                          
                                                                
                                                              














































































































































































































































































































































                                                                                

                                                           

                                                          



                                                        

















































































































                                                                               
                                         














































































































































































































































































                                                                                
/*
 * iSCSI Initiator over TCP/IP Data-Path
 *
 * Copyright (C) 2004 Dmitry Yusupov
 * Copyright (C) 2004 Alex Aizman
 * Copyright (C) 2005 Mike Christie
 * maintained by open-iscsi@googlegroups.com
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 *
 * This program 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.
 *
 * See the file COPYING included with this distribution for more details.
 *
 * Credits:
 *	Christoph Hellwig
 *	FUJITA Tomonori
 *	Arne Redlich
 *	Zhenyu Wang
 */

#include <linux/types.h>
#include <linux/list.h>
#include <linux/inet.h>
#include <linux/blkdev.h>
#include <linux/crypto.h>
#include <linux/delay.h>
#include <linux/kfifo.h>
#include <linux/scatterlist.h>
#include <net/tcp.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_request.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi.h>
#include <scsi/scsi_transport_iscsi.h>

#include "iscsi_tcp.h"

MODULE_AUTHOR("Dmitry Yusupov <dmitry_yus@yahoo.com>, "
	      "Alex Aizman <itn780@yahoo.com>");
MODULE_DESCRIPTION("iSCSI/TCP data-path");
MODULE_LICENSE("GPL");
MODULE_VERSION("0:4.445");
/* #define DEBUG_TCP */
/* #define DEBUG_SCSI */
#define DEBUG_ASSERT

#ifdef DEBUG_TCP
#define debug_tcp(fmt...) printk(KERN_DEBUG "tcp: " fmt)
#else
#define debug_tcp(fmt...)
#endif

#ifdef DEBUG_SCSI
#define debug_scsi(fmt...) printk(KERN_DEBUG "scsi: " fmt)
#else
#define debug_scsi(fmt...)
#endif

#ifndef DEBUG_ASSERT
#ifdef BUG_ON
#undef BUG_ON
#endif
#define BUG_ON(expr)
#endif

#define INVALID_SN_DELTA	0xffff

static unsigned int iscsi_max_lun = 512;
module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);

/* global data */
static kmem_cache_t *taskcache;

static inline void
iscsi_buf_init_virt(struct iscsi_buf *ibuf, char *vbuf, int size)
{
	sg_init_one(&ibuf->sg, (u8 *)vbuf, size);
	ibuf->sent = 0;
}

static inline void
iscsi_buf_init_iov(struct iscsi_buf *ibuf, char *vbuf, int size)
{
	ibuf->sg.page = (void*)vbuf;
	ibuf->sg.offset = (unsigned int)-1;
	ibuf->sg.length = size;
	ibuf->sent = 0;
}

static inline void*
iscsi_buf_iov_base(struct iscsi_buf *ibuf)
{
	return (char*)ibuf->sg.page + ibuf->sent;
}

static inline void
iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
{
	/*
	 * Fastpath: sg element fits into single page
	 */
	if (sg->length + sg->offset <= PAGE_SIZE && page_count(sg->page) >= 2) {
		ibuf->sg.page = sg->page;
		ibuf->sg.offset = sg->offset;
		ibuf->sg.length = sg->length;
	} else
		iscsi_buf_init_iov(ibuf, page_address(sg->page), sg->length);
	ibuf->sent = 0;
}

static inline int
iscsi_buf_left(struct iscsi_buf *ibuf)
{
	int rc;

	rc = ibuf->sg.length - ibuf->sent;
	BUG_ON(rc < 0);
	return rc;
}

static inline void
iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
		 u8* crc)
{
	crypto_digest_digest(conn->tx_tfm, &buf->sg, 1, crc);
	buf->sg.length += sizeof(uint32_t);
}

static void
iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
{
	struct iscsi_session *session = conn->session;
	unsigned long flags;

	spin_lock_irqsave(&session->lock, flags);
	if (session->conn_cnt == 1 || session->leadconn == conn)
		session->state = ISCSI_STATE_FAILED;
	spin_unlock_irqrestore(&session->lock, flags);
	set_bit(SUSPEND_BIT, &conn->suspend_tx);
	set_bit(SUSPEND_BIT, &conn->suspend_rx);
	iscsi_conn_error(iscsi_handle(conn), err);
}

static inline int
iscsi_check_assign_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
{
	uint32_t max_cmdsn = be32_to_cpu(hdr->max_cmdsn);
	uint32_t exp_cmdsn = be32_to_cpu(hdr->exp_cmdsn);

	if (max_cmdsn < exp_cmdsn -1 &&
	    max_cmdsn > exp_cmdsn - INVALID_SN_DELTA)
		return ISCSI_ERR_MAX_CMDSN;
	if (max_cmdsn > session->max_cmdsn ||
	    max_cmdsn < session->max_cmdsn - INVALID_SN_DELTA)
		session->max_cmdsn = max_cmdsn;
	if (exp_cmdsn > session->exp_cmdsn ||
	    exp_cmdsn < session->exp_cmdsn - INVALID_SN_DELTA)
		session->exp_cmdsn = exp_cmdsn;

	return 0;
}

static inline int
iscsi_hdr_extract(struct iscsi_conn *conn)
{
	struct sk_buff *skb = conn->in.skb;

	if (conn->in.copy >= conn->hdr_size &&
	    conn->in_progress == IN_PROGRESS_WAIT_HEADER) {
		/*
		 * Zero-copy PDU Header: using connection context
		 * to store header pointer.
		 */
		if (skb_shinfo(skb)->frag_list == NULL &&
		    !skb_shinfo(skb)->nr_frags)
			conn->in.hdr = (struct iscsi_hdr *)
				((char*)skb->data + conn->in.offset);
		else {
			/* ignoring return code since we checked
			 * in.copy before */
			skb_copy_bits(skb, conn->in.offset,
				&conn->hdr, conn->hdr_size);
			conn->in.hdr = &conn->hdr;
		}
		conn->in.offset += conn->hdr_size;
		conn->in.copy -= conn->hdr_size;
	} else {
		int hdr_remains;
		int copylen;

		/*
		 * PDU header scattered across SKB's,
		 * copying it... This'll happen quite rarely.
		 */

		if (conn->in_progress == IN_PROGRESS_WAIT_HEADER)
			conn->in.hdr_offset = 0;

		hdr_remains = conn->hdr_size - conn->in.hdr_offset;
		BUG_ON(hdr_remains <= 0);

		copylen = min(conn->in.copy, hdr_remains);
		skb_copy_bits(skb, conn->in.offset,
			(char*)&conn->hdr + conn->in.hdr_offset, copylen);

		debug_tcp("PDU gather offset %d bytes %d in.offset %d "
		       "in.copy %d\n", conn->in.hdr_offset, copylen,
		       conn->in.offset, conn->in.copy);

		conn->in.offset += copylen;
		conn->in.copy -= copylen;
		if (copylen < hdr_remains)  {
			conn->in_progress = IN_PROGRESS_HEADER_GATHER;
			conn->in.hdr_offset += copylen;
		        return -EAGAIN;
		}
		conn->in.hdr = &conn->hdr;
		conn->discontiguous_hdr_cnt++;
	        conn->in_progress = IN_PROGRESS_WAIT_HEADER;
	}

	return 0;
}

static inline void
iscsi_ctask_cleanup(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct scsi_cmnd *sc = ctask->sc;
	struct iscsi_session *session = conn->session;

	spin_lock(&session->lock);
	if (unlikely(!sc)) {
		spin_unlock(&session->lock);
		return;
	}
	if (sc->sc_data_direction == DMA_TO_DEVICE) {
		struct iscsi_data_task *dtask, *n;
		/* WRITE: cleanup Data-Out's if any */
		spin_lock(&conn->lock);
		list_for_each_entry_safe(dtask, n, &ctask->dataqueue, item) {
			list_del(&dtask->item);
			mempool_free(dtask, ctask->datapool);
		}
		spin_unlock(&conn->lock);
	}
	ctask->xmstate = XMSTATE_IDLE;
	ctask->r2t = NULL;
	ctask->sc = NULL;
	__kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
	spin_unlock(&session->lock);
}

/**
 * iscsi_cmd_rsp - SCSI Command Response processing
 * @conn: iscsi connection
 * @ctask: scsi command task
 **/
static int
iscsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	int rc;
	struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)conn->in.hdr;
	struct iscsi_session *session = conn->session;
	struct scsi_cmnd *sc = ctask->sc;

	rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
	if (rc) {
		sc->result = (DID_ERROR << 16);
		goto out;
	}

	conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;

	sc->result = (DID_OK << 16) | rhdr->cmd_status;

	if (rhdr->response != ISCSI_STATUS_CMD_COMPLETED) {
		sc->result = (DID_ERROR << 16);
		goto out;
	}

	if (rhdr->cmd_status == SAM_STAT_CHECK_CONDITION && conn->senselen) {
		int sensecopy = min(conn->senselen, SCSI_SENSE_BUFFERSIZE);

		memcpy(sc->sense_buffer, conn->data + 2, sensecopy);
		debug_scsi("copied %d bytes of sense\n", sensecopy);
	}

	if (sc->sc_data_direction == DMA_TO_DEVICE)
		goto out;

	if (rhdr->flags & ISCSI_FLAG_CMD_UNDERFLOW) {
		int res_count = be32_to_cpu(rhdr->residual_count);

		if (res_count > 0 && res_count <= sc->request_bufflen)
			sc->resid = res_count;
		else
			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
	} else if (rhdr->flags & ISCSI_FLAG_CMD_BIDI_UNDERFLOW)
		sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
	else if (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW)
		sc->resid = be32_to_cpu(rhdr->residual_count);

out:
	debug_scsi("done [sc %lx res %d itt 0x%x]\n",
		   (long)sc, sc->result, ctask->itt);
	conn->scsirsp_pdus_cnt++;
	iscsi_ctask_cleanup(conn, ctask);
	sc->scsi_done(sc);
	return rc;
}

/**
 * iscsi_data_rsp - SCSI Data-In Response processing
 * @conn: iscsi connection
 * @ctask: scsi command task
 **/
static int
iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	int rc;
	struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)conn->in.hdr;
	struct iscsi_session *session = conn->session;
	int datasn = be32_to_cpu(rhdr->datasn);

	rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
	if (rc)
		return rc;
	/*
	 * setup Data-In byte counter (gets decremented..)
	 */
	ctask->data_count = conn->in.datalen;

	if (conn->in.datalen == 0)
		return 0;

	if (ctask->datasn != datasn)
		return ISCSI_ERR_DATASN;

	ctask->datasn++;

	ctask->data_offset = be32_to_cpu(rhdr->offset);
	if (ctask->data_offset + conn->in.datalen > ctask->total_length)
		return ISCSI_ERR_DATA_OFFSET;

	if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
		struct scsi_cmnd *sc = ctask->sc;

		conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
		if (rhdr->flags & ISCSI_FLAG_CMD_UNDERFLOW) {
			int res_count = be32_to_cpu(rhdr->residual_count);

			if (res_count > 0 &&
			    res_count <= sc->request_bufflen) {
				sc->resid = res_count;
				sc->result = (DID_OK << 16) | rhdr->cmd_status;
			} else
				sc->result = (DID_BAD_TARGET << 16) |
					rhdr->cmd_status;
		} else if (rhdr->flags & ISCSI_FLAG_CMD_BIDI_UNDERFLOW)
			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
		else if (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW) {
			sc->resid = be32_to_cpu(rhdr->residual_count);
			sc->result = (DID_OK << 16) | rhdr->cmd_status;
		} else
			sc->result = (DID_OK << 16) | rhdr->cmd_status;
	}

	conn->datain_pdus_cnt++;
	return 0;
}

/**
 * iscsi_solicit_data_init - initialize first Data-Out
 * @conn: iscsi connection
 * @ctask: scsi command task
 * @r2t: R2T info
 *
 * Notes:
 *	Initialize first Data-Out within this R2T sequence and finds
 *	proper data_offset within this SCSI command.
 *
 *	This function is called with connection lock taken.
 **/
static void
iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
			struct iscsi_r2t_info *r2t)
{
	struct iscsi_data *hdr;
	struct iscsi_data_task *dtask;
	struct scsi_cmnd *sc = ctask->sc;

	dtask = mempool_alloc(ctask->datapool, GFP_ATOMIC);
	BUG_ON(!dtask);
	hdr = &dtask->hdr;
	memset(hdr, 0, sizeof(struct iscsi_data));
	hdr->ttt = r2t->ttt;
	hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
	r2t->solicit_datasn++;
	hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
	memcpy(hdr->lun, ctask->hdr.lun, sizeof(hdr->lun));
	hdr->itt = ctask->hdr.itt;
	hdr->exp_statsn = r2t->exp_statsn;
	hdr->offset = cpu_to_be32(r2t->data_offset);
	if (r2t->data_length > conn->max_xmit_dlength) {
		hton24(hdr->dlength, conn->max_xmit_dlength);
		r2t->data_count = conn->max_xmit_dlength;
		hdr->flags = 0;
	} else {
		hton24(hdr->dlength, r2t->data_length);
		r2t->data_count = r2t->data_length;
		hdr->flags = ISCSI_FLAG_CMD_FINAL;
	}
	conn->dataout_pdus_cnt++;

	r2t->sent = 0;

	iscsi_buf_init_virt(&r2t->headbuf, (char*)hdr,
			   sizeof(struct iscsi_hdr));

	r2t->dtask = dtask;

	if (sc->use_sg) {
		int i, sg_count = 0;
		struct scatterlist *sg = sc->request_buffer;

		r2t->sg = NULL;
		for (i = 0; i < sc->use_sg; i++, sg += 1) {
			/* FIXME: prefetch ? */
			if (sg_count + sg->length > r2t->data_offset) {
				int page_offset;

				/* sg page found! */

				/* offset within this page */
				page_offset = r2t->data_offset - sg_count;

				/* fill in this buffer */
				iscsi_buf_init_sg(&r2t->sendbuf, sg);
				r2t->sendbuf.sg.offset += page_offset;
				r2t->sendbuf.sg.length -= page_offset;

				/* xmit logic will continue with next one */
				r2t->sg = sg + 1;
				break;
			}
			sg_count += sg->length;
		}
		BUG_ON(r2t->sg == NULL);
	} else
		iscsi_buf_init_iov(&ctask->sendbuf,
			    (char*)sc->request_buffer + r2t->data_offset,
			    r2t->data_count);

	list_add(&dtask->item, &ctask->dataqueue);
}

/**
 * iscsi_r2t_rsp - iSCSI R2T Response processing
 * @conn: iscsi connection
 * @ctask: scsi command task
 **/
static int
iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_r2t_info *r2t;
	struct iscsi_session *session = conn->session;
	struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)conn->in.hdr;
	int r2tsn = be32_to_cpu(rhdr->r2tsn);
	int rc;

	if (conn->in.ahslen)
		return ISCSI_ERR_AHSLEN;

	if (conn->in.datalen)
		return ISCSI_ERR_DATALEN;

	if (ctask->exp_r2tsn && ctask->exp_r2tsn != r2tsn)
		return ISCSI_ERR_R2TSN;

	rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
	if (rc)
		return rc;

	/* FIXME: use R2TSN to detect missing R2T */

	/* fill-in new R2T associated with the task */
	spin_lock(&session->lock);
	if (!ctask->sc || ctask->mtask ||
	     session->state != ISCSI_STATE_LOGGED_IN) {
		printk(KERN_INFO "iscsi_tcp: dropping R2T itt %d in "
		       "recovery...\n", ctask->itt);
		spin_unlock(&session->lock);
		return 0;
	}
	rc = __kfifo_get(ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
	BUG_ON(!rc);

	r2t->exp_statsn = rhdr->statsn;
	r2t->data_length = be32_to_cpu(rhdr->data_length);
	if (r2t->data_length == 0 ||
	    r2t->data_length > session->max_burst) {
		spin_unlock(&session->lock);
		return ISCSI_ERR_DATALEN;
	}

	r2t->data_offset = be32_to_cpu(rhdr->data_offset);
	if (r2t->data_offset + r2t->data_length > ctask->total_length) {
		spin_unlock(&session->lock);
		return ISCSI_ERR_DATALEN;
	}

	r2t->ttt = rhdr->ttt; /* no flip */
	r2t->solicit_datasn = 0;

	iscsi_solicit_data_init(conn, ctask, r2t);

	ctask->exp_r2tsn = r2tsn + 1;
	ctask->xmstate |= XMSTATE_SOL_HDR;
	__kfifo_put(ctask->r2tqueue, (void*)&r2t, sizeof(void*));
	__kfifo_put(conn->writequeue, (void*)&ctask, sizeof(void*));

	schedule_work(&conn->xmitwork);
	conn->r2t_pdus_cnt++;
	spin_unlock(&session->lock);

	return 0;
}

static int
iscsi_hdr_recv(struct iscsi_conn *conn)
{
	int rc = 0;
	struct iscsi_hdr *hdr;
	struct iscsi_cmd_task *ctask;
	struct iscsi_session *session = conn->session;
	uint32_t cdgst, rdgst = 0;

	hdr = conn->in.hdr;

	/* verify PDU length */
	conn->in.datalen = ntoh24(hdr->dlength);
	if (conn->in.datalen > conn->max_recv_dlength) {
		printk(KERN_ERR "iscsi_tcp: datalen %d > %d\n",
		       conn->in.datalen, conn->max_recv_dlength);
		return ISCSI_ERR_DATALEN;
	}
	conn->data_copied = 0;

	/* read AHS */
	conn->in.ahslen = hdr->hlength * 4;
	conn->in.offset += conn->in.ahslen;
	conn->in.copy -= conn->in.ahslen;
	if (conn->in.copy < 0) {
		printk(KERN_ERR "iscsi_tcp: can't handle AHS with length "
		       "%d bytes\n", conn->in.ahslen);
		return ISCSI_ERR_AHSLEN;
	}

	/* calculate read padding */
	conn->in.padding = conn->in.datalen & (ISCSI_PAD_LEN-1);
	if (conn->in.padding) {
		conn->in.padding = ISCSI_PAD_LEN - conn->in.padding;
		debug_scsi("read padding %d bytes\n", conn->in.padding);
	}

	if (conn->hdrdgst_en) {
		struct scatterlist sg;

		sg_init_one(&sg, (u8 *)hdr,
			    sizeof(struct iscsi_hdr) + conn->in.ahslen);
		crypto_digest_digest(conn->rx_tfm, &sg, 1, (u8 *)&cdgst);
		rdgst = *(uint32_t*)((char*)hdr + sizeof(struct iscsi_hdr) +
				     conn->in.ahslen);
		if (cdgst != rdgst) {
			printk(KERN_ERR "iscsi_tcp: itt %x: hdrdgst error "
			       "recv 0x%x calc 0x%x\n", conn->in.itt, rdgst,
			       cdgst);
			return ISCSI_ERR_HDR_DGST;
		}
	}

	/* save opcode for later */
	conn->in.opcode = hdr->opcode & ISCSI_OPCODE_MASK;

	/* verify itt (itt encoding: age+cid+itt) */
	if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG)) {
		if ((hdr->itt & AGE_MASK) !=
				(session->age << AGE_SHIFT)) {
			printk(KERN_ERR "iscsi_tcp: received itt %x expected "
				"session age (%x)\n", hdr->itt,
				session->age & AGE_MASK);
			return ISCSI_ERR_BAD_ITT;
		}

		if ((hdr->itt & CID_MASK) != (conn->id << CID_SHIFT)) {
			printk(KERN_ERR "iscsi_tcp: received itt %x, expected "
				"CID (%x)\n", hdr->itt, conn->id);
			return ISCSI_ERR_BAD_ITT;
		}
		conn->in.itt = hdr->itt & ITT_MASK;
	} else
		conn->in.itt = hdr->itt;

	debug_tcp("opcode 0x%x offset %d copy %d ahslen %d datalen %d\n",
		  hdr->opcode, conn->in.offset, conn->in.copy,
		  conn->in.ahslen, conn->in.datalen);

	if (conn->in.itt < session->cmds_max) {
		ctask = (struct iscsi_cmd_task *)session->cmds[conn->in.itt];

		if (!ctask->sc) {
			printk(KERN_INFO "iscsi_tcp: dropping ctask with "
			       "itt 0x%x\n", ctask->itt);
			conn->in.datalen = 0; /* force drop */
			return 0;
		}

		if (ctask->sc->SCp.phase != session->age) {
			printk(KERN_ERR "iscsi_tcp: ctask's session age %d, "
				"expected %d\n", ctask->sc->SCp.phase,
				session->age);
			return ISCSI_ERR_SESSION_FAILED;
		}

		conn->in.ctask = ctask;

		debug_scsi("rsp [op 0x%x cid %d sc %lx itt 0x%x len %d]\n",
			   hdr->opcode, conn->id, (long)ctask->sc,
			   ctask->itt, conn->in.datalen);

		switch(conn->in.opcode) {
		case ISCSI_OP_SCSI_CMD_RSP:
			BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
			if (!conn->in.datalen)
				rc = iscsi_cmd_rsp(conn, ctask);
			else
				/*
				 * got sense or response data; copying PDU
				 * Header to the connection's header
				 * placeholder
				 */
				memcpy(&conn->hdr, hdr,
				       sizeof(struct iscsi_hdr));
			break;
		case ISCSI_OP_SCSI_DATA_IN:
			BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
			/* save flags for non-exceptional status */
			conn->in.flags = hdr->flags;
			/* save cmd_status for sense data */
			conn->in.cmd_status =
				((struct iscsi_data_rsp*)hdr)->cmd_status;
			rc = iscsi_data_rsp(conn, ctask);
			break;
		case ISCSI_OP_R2T:
			BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
			if (ctask->sc->sc_data_direction == DMA_TO_DEVICE)
				rc = iscsi_r2t_rsp(conn, ctask);
			else
				rc = ISCSI_ERR_PROTO;
			break;
		default:
			rc = ISCSI_ERR_BAD_OPCODE;
			break;
		}
	} else if (conn->in.itt >= ISCSI_MGMT_ITT_OFFSET &&
		   conn->in.itt < ISCSI_MGMT_ITT_OFFSET +
					session->mgmtpool_max) {
		struct iscsi_mgmt_task *mtask = (struct iscsi_mgmt_task *)
					session->mgmt_cmds[conn->in.itt -
						ISCSI_MGMT_ITT_OFFSET];

		debug_scsi("immrsp [op 0x%x cid %d itt 0x%x len %d]\n",
			   conn->in.opcode, conn->id, mtask->itt,
			   conn->in.datalen);

		switch(conn->in.opcode) {
		case ISCSI_OP_LOGIN_RSP:
		case ISCSI_OP_TEXT_RSP:
		case ISCSI_OP_LOGOUT_RSP: 
			rc = iscsi_check_assign_cmdsn(session,
						 (struct iscsi_nopin*)hdr);
			if (rc)
				break;

			if (!conn->in.datalen) {
				rc = iscsi_recv_pdu(iscsi_handle(conn), hdr,
						    NULL, 0);
				if (conn->login_mtask != mtask) {
					spin_lock(&session->lock);
					__kfifo_put(session->mgmtpool.queue,
					    (void*)&mtask, sizeof(void*));
					spin_unlock(&session->lock);
				}
			}
			break;
		case ISCSI_OP_SCSI_TMFUNC_RSP:
			rc = iscsi_check_assign_cmdsn(session,
						 (struct iscsi_nopin*)hdr);
			if (rc)
				break;

			if (conn->in.datalen || conn->in.ahslen) {
				rc = ISCSI_ERR_PROTO;
				break;
			}
			conn->tmfrsp_pdus_cnt++;
			spin_lock(&session->lock);
			if (conn->tmabort_state == TMABORT_INITIAL) {
				__kfifo_put(session->mgmtpool.queue,
						(void*)&mtask, sizeof(void*));
				conn->tmabort_state =
					((struct iscsi_tm_rsp *)hdr)->
					response == ISCSI_TMF_RSP_COMPLETE ?
						TMABORT_SUCCESS:TMABORT_FAILED;
				/* unblock eh_abort() */
				wake_up(&conn->ehwait);
			}
			spin_unlock(&session->lock);
			break;
		case ISCSI_OP_NOOP_IN: 
			if (hdr->ttt != ISCSI_RESERVED_TAG) {
				rc = ISCSI_ERR_PROTO;
				break;
			}
			rc = iscsi_check_assign_cmdsn(session, 
						(struct iscsi_nopin*)hdr);
			if (rc)
				break;
			conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;

			if (!conn->in.datalen) {
				struct iscsi_mgmt_task *mtask;

				rc = iscsi_recv_pdu(iscsi_handle(conn), hdr,
						    NULL, 0);
				mtask = (struct iscsi_mgmt_task *)
					session->mgmt_cmds[conn->in.itt -
							ISCSI_MGMT_ITT_OFFSET];
				if (conn->login_mtask != mtask) {
					spin_lock(&session->lock);
					__kfifo_put(session->mgmtpool.queue,
						  (void*)&mtask, sizeof(void*));
					spin_unlock(&session->lock);
				}
			}
			break;
		default:
			rc = ISCSI_ERR_BAD_OPCODE;
			break;
		}
	} else if (conn->in.itt == ISCSI_RESERVED_TAG) {
		switch(conn->in.opcode) {
		case ISCSI_OP_NOOP_IN:
			if (!conn->in.datalen) {
				rc = iscsi_check_assign_cmdsn(session,
						 (struct iscsi_nopin*)hdr);
				if (!rc && hdr->ttt != ISCSI_RESERVED_TAG)
					rc = iscsi_recv_pdu(iscsi_handle(conn),
							    hdr, NULL, 0);
			} else 
				rc = ISCSI_ERR_PROTO;
			break;
		case ISCSI_OP_REJECT:
			/* we need sth like iscsi_reject_rsp()*/
		case ISCSI_OP_ASYNC_EVENT:
			/* we need sth like iscsi_async_event_rsp() */
			rc = ISCSI_ERR_BAD_OPCODE;
			break;
		default:
			rc = ISCSI_ERR_BAD_OPCODE;
			break;
		}
	} else
		rc = ISCSI_ERR_BAD_ITT;

	return rc;
}

/**
 * iscsi_ctask_copy - copy skb bits to the destanation cmd task
 * @conn: iscsi connection
 * @ctask: scsi command task
 * @buf: buffer to copy to
 * @buf_size: size of buffer
 * @offset: offset within the buffer
 *
 * Notes:
 *	The function calls skb_copy_bits() and updates per-connection and
 *	per-cmd byte counters.
 *
 *	Read counters (in bytes):
 *
 *	conn->in.offset		offset within in progress SKB
 *	conn->in.copy		left to copy from in progress SKB
 *				including padding
 *	conn->in.copied		copied already from in progress SKB
 *	conn->data_copied	copied already from in progress buffer
 *	ctask->sent		total bytes sent up to the MidLayer
 *	ctask->data_count	left to copy from in progress Data-In
 *	buf_left		left to copy from in progress buffer
 **/
static inline int
iscsi_ctask_copy(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
		void *buf, int buf_size, int offset)
{
	int buf_left = buf_size - (conn->data_copied + offset);
	int size = min(conn->in.copy, buf_left);
	int rc;

	size = min(size, ctask->data_count);

	debug_tcp("ctask_copy %d bytes at offset %d copied %d\n",
	       size, conn->in.offset, conn->in.copied);

	BUG_ON(size <= 0);
	BUG_ON(ctask->sent + size > ctask->total_length);

	rc = skb_copy_bits(conn->in.skb, conn->in.offset,
			   (char*)buf + (offset + conn->data_copied), size);
	/* must fit into skb->len */
	BUG_ON(rc);

	conn->in.offset += size;
	conn->in.copy -= size;
	conn->in.copied += size;
	conn->data_copied += size;
	ctask->sent += size;
	ctask->data_count -= size;

	BUG_ON(conn->in.copy < 0);
	BUG_ON(ctask->data_count < 0);

	if (buf_size != (conn->data_copied + offset)) {
		if (!ctask->data_count) {
			BUG_ON(buf_size - conn->data_copied < 0);
			/* done with this PDU */
			return buf_size - conn->data_copied;
		}
		return -EAGAIN;
	}

	/* done with this buffer or with both - PDU and buffer */
	conn->data_copied = 0;
	return 0;
}

/**
 * iscsi_tcp_copy - copy skb bits to the destanation buffer
 * @conn: iscsi connection
 * @buf: buffer to copy to
 * @buf_size: number of bytes to copy
 *
 * Notes:
 *	The function calls skb_copy_bits() and updates per-connection
 *	byte counters.
 **/
static inline int
iscsi_tcp_copy(struct iscsi_conn *conn, void *buf, int buf_size)
{
	int buf_left = buf_size - conn->data_copied;
	int size = min(conn->in.copy, buf_left);
	int rc;

	debug_tcp("tcp_copy %d bytes at offset %d copied %d\n",
	       size, conn->in.offset, conn->data_copied);
	BUG_ON(size <= 0);

	rc = skb_copy_bits(conn->in.skb, conn->in.offset,
			   (char*)buf + conn->data_copied, size);
	BUG_ON(rc);

	conn->in.offset += size;
	conn->in.copy -= size;
	conn->in.copied += size;
	conn->data_copied += size;

	if (buf_size != conn->data_copied)
		return -EAGAIN;

	return 0;
}

static inline void
partial_sg_digest_update(struct iscsi_conn *conn, struct scatterlist *sg,
			 int offset, int length)
{
	struct scatterlist temp;

	memcpy(&temp, sg, sizeof(struct scatterlist));
	temp.offset = offset;
	temp.length = length;
	crypto_digest_update(conn->data_rx_tfm, &temp, 1);
}

static void
iscsi_recv_digest_update(struct iscsi_conn *conn, char* buf, int len)
{
	struct scatterlist tmp;

	sg_init_one(&tmp, buf, len);
	crypto_digest_update(conn->data_rx_tfm, &tmp, 1);
}

static int iscsi_scsi_data_in(struct iscsi_conn *conn)
{
	struct iscsi_cmd_task *ctask = conn->in.ctask;
	struct scsi_cmnd *sc = ctask->sc;
	struct scatterlist *sg;
	int i, offset, rc = 0;

	BUG_ON((void*)ctask != sc->SCp.ptr);

	/*
	 * copying Data-In into the Scsi_Cmnd
	 */
	if (!sc->use_sg) {
		i = ctask->data_count;
		rc = iscsi_ctask_copy(conn, ctask, sc->request_buffer,
				      sc->request_bufflen, ctask->data_offset);
		if (rc == -EAGAIN)
			return rc;
		if (conn->datadgst_en) 
			iscsi_recv_digest_update(conn, sc->request_buffer, i);
		rc = 0;
		goto done;
	}

	offset = ctask->data_offset;
	sg = sc->request_buffer;

	if (ctask->data_offset)
		for (i = 0; i < ctask->sg_count; i++)
			offset -= sg[i].length;
	/* we've passed through partial sg*/
	if (offset < 0)
		offset = 0;

	for (i = ctask->sg_count; i < sc->use_sg; i++) {
		char *dest;

		dest = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
		rc = iscsi_ctask_copy(conn, ctask, dest + sg[i].offset,
				      sg[i].length, offset);
		kunmap_atomic(dest, KM_SOFTIRQ0);
		if (rc == -EAGAIN)
			/* continue with the next SKB/PDU */
			return rc;
		if (!rc) {
			if (conn->datadgst_en) {
				if (!offset)
					crypto_digest_update(conn->data_rx_tfm,
							     &sg[i], 1);
				else
					partial_sg_digest_update(conn, &sg[i],
							sg[i].offset + offset,
							sg[i].length - offset);
			}
			offset = 0;
			ctask->sg_count++;
		}

		if (!ctask->data_count) {
			if (rc && conn->datadgst_en)
				/*
				 * data-in is complete, but buffer not...
				 */
				partial_sg_digest_update(conn, &sg[i],
						sg[i].offset, sg[i].length-rc);
			rc = 0;
			break;
		}

		if (!conn->in.copy)
			return -EAGAIN;
	}
	BUG_ON(ctask->data_count);

done:
	/* check for non-exceptional status */
	if (conn->in.flags & ISCSI_FLAG_DATA_STATUS) {
		debug_scsi("done [sc %lx res %d itt 0x%x]\n",
			   (long)sc, sc->result, ctask->itt);
		conn->scsirsp_pdus_cnt++;
		iscsi_ctask_cleanup(conn, ctask);
		sc->scsi_done(sc);
	}

	return rc;
}

static int
iscsi_data_recv(struct iscsi_conn *conn)
{
	struct iscsi_session *session = conn->session;
	int rc = 0;

	switch(conn->in.opcode) {
	case ISCSI_OP_SCSI_DATA_IN:
		rc = iscsi_scsi_data_in(conn);
		break;
	case ISCSI_OP_SCSI_CMD_RSP: {
		/*
		 * SCSI Sense Data:
		 * copying the entire Data Segment.
		 */
		if (iscsi_tcp_copy(conn, conn->data, conn->in.datalen)) {
			rc = -EAGAIN;
			goto exit;
		}

		/*
		 * check for sense
		 */
		conn->in.hdr = &conn->hdr;
		conn->senselen = (conn->data[0] << 8) | conn->data[1];
		rc = iscsi_cmd_rsp(conn, conn->in.ctask);
		if (!rc && conn->datadgst_en) 
			iscsi_recv_digest_update(conn, conn->data,
						 conn->in.datalen);
	}
	break;
	case ISCSI_OP_TEXT_RSP:
	case ISCSI_OP_LOGIN_RSP:
	case ISCSI_OP_NOOP_IN: {
		struct iscsi_mgmt_task *mtask = NULL;

		if (conn->in.itt != ISCSI_RESERVED_TAG)
			mtask = (struct iscsi_mgmt_task *)
				session->mgmt_cmds[conn->in.itt -
					ISCSI_MGMT_ITT_OFFSET];

		/*
		 * Collect data segment to the connection's data
		 * placeholder
		 */
		if (iscsi_tcp_copy(conn, conn->data, conn->in.datalen)) {
			rc = -EAGAIN;
			goto exit;
		}

		rc = iscsi_recv_pdu(iscsi_handle(conn), conn->in.hdr,
				    conn->data, conn->in.datalen);

		if (!rc && conn->datadgst_en && 
			conn->in.opcode != ISCSI_OP_LOGIN_RSP)
			iscsi_recv_digest_update(conn, conn->data,
			  			conn->in.datalen);

		if (mtask && conn->login_mtask != mtask) {
			spin_lock(&session->lock);
			__kfifo_put(session->mgmtpool.queue, (void*)&mtask,
				    sizeof(void*));
			spin_unlock(&session->lock);
		}
	}
	break;
	case ISCSI_OP_ASYNC_EVENT:
	case ISCSI_OP_REJECT:
	default:
		BUG_ON(1);
	}
exit:
	return rc;
}

/**
 * iscsi_tcp_data_recv - TCP receive in sendfile fashion
 * @rd_desc: read descriptor
 * @skb: socket buffer
 * @offset: offset in skb
 * @len: skb->len - offset
 **/
static int
iscsi_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
		unsigned int offset, size_t len)
{
	int rc;
	struct iscsi_conn *conn = rd_desc->arg.data;
	int processed;
	char pad[ISCSI_PAD_LEN];
	struct scatterlist sg;

	/*
	 * Save current SKB and its offset in the corresponding
	 * connection context.
	 */
	conn->in.copy = skb->len - offset;
	conn->in.offset = offset;
	conn->in.skb = skb;
	conn->in.len = conn->in.copy;
	BUG_ON(conn->in.copy <= 0);
	debug_tcp("in %d bytes\n", conn->in.copy);

more:
	conn->in.copied = 0;
	rc = 0;

	if (unlikely(conn->suspend_rx)) {
		debug_tcp("conn %d Rx suspended!\n", conn->id);
		return 0;
	}

	if (conn->in_progress == IN_PROGRESS_WAIT_HEADER ||
	    conn->in_progress == IN_PROGRESS_HEADER_GATHER) {
		rc = iscsi_hdr_extract(conn);
		if (rc) {
		       if (rc == -EAGAIN)
				goto nomore;
		       else {
				iscsi_conn_failure(conn, rc);
				return 0;
		       }
		}

		/*
		 * Verify and process incoming PDU header.
		 */
		rc = iscsi_hdr_recv(conn);
		if (!rc && conn->in.datalen) {
			if (conn->datadgst_en) {
				BUG_ON(!conn->data_rx_tfm);
				crypto_digest_init(conn->data_rx_tfm);
			}
			conn->in_progress = IN_PROGRESS_DATA_RECV;
		} else if (rc) {
			iscsi_conn_failure(conn, rc);
			return 0;
		}
	}

	if (conn->in_progress == IN_PROGRESS_DDIGEST_RECV) {
		uint32_t recv_digest;
		debug_tcp("extra data_recv offset %d copy %d\n",
			  conn->in.offset, conn->in.copy);
		skb_copy_bits(conn->in.skb, conn->in.offset,
				&recv_digest, 4);
		conn->in.offset += 4;
		conn->in.copy -= 4;
		if (recv_digest != conn->in.datadgst) {
			debug_tcp("iscsi_tcp: data digest error!"
				  "0x%x != 0x%x\n", recv_digest,
				  conn->in.datadgst);
			iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
			return 0;
		} else {
			debug_tcp("iscsi_tcp: data digest match!"
				  "0x%x == 0x%x\n", recv_digest,
				  conn->in.datadgst);
			conn->in_progress = IN_PROGRESS_WAIT_HEADER;
		}
	}

	if (conn->in_progress == IN_PROGRESS_DATA_RECV && conn->in.copy) {

		debug_tcp("data_recv offset %d copy %d\n",
		       conn->in.offset, conn->in.copy);

		rc = iscsi_data_recv(conn);
		if (rc) {
			if (rc == -EAGAIN) {
				rd_desc->count = conn->in.datalen -
						conn->in.ctask->data_count;
				goto again;
			}
			iscsi_conn_failure(conn, rc);
			return 0;
		}
		conn->in.copy -= conn->in.padding;
		conn->in.offset += conn->in.padding;
		if (conn->datadgst_en) {
			if (conn->in.padding) {
				debug_tcp("padding -> %d\n", conn->in.padding);
				memset(pad, 0, conn->in.padding);
				sg_init_one(&sg, pad, conn->in.padding);
				crypto_digest_update(conn->data_rx_tfm, &sg, 1);
			}
			crypto_digest_final(conn->data_rx_tfm,
					    (u8 *) & conn->in.datadgst);
			debug_tcp("rx digest 0x%x\n", conn->in.datadgst);
			conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
		} else
			conn->in_progress = IN_PROGRESS_WAIT_HEADER;
	}

	debug_tcp("f, processed %d from out of %d padding %d\n",
	       conn->in.offset - offset, (int)len, conn->in.padding);
	BUG_ON(conn->in.offset - offset > len);

	if (conn->in.offset - offset != len) {
		debug_tcp("continue to process %d bytes\n",
		       (int)len - (conn->in.offset - offset));
		goto more;
	}

nomore:
	processed = conn->in.offset - offset;
	BUG_ON(processed == 0);
	return processed;

again:
	processed = conn->in.offset - offset;
	debug_tcp("c, processed %d from out of %d rd_desc_cnt %d\n",
	          processed, (int)len, (int)rd_desc->count);
	BUG_ON(processed == 0);
	BUG_ON(processed > len);

	conn->rxdata_octets += processed;
	return processed;
}

static void
iscsi_tcp_data_ready(struct sock *sk, int flag)
{
	struct iscsi_conn *conn = sk->sk_user_data;
	read_descriptor_t rd_desc;

	read_lock(&sk->sk_callback_lock);

	/* use rd_desc to pass 'conn' to iscsi_tcp_data_recv */
	rd_desc.arg.data = conn;
	rd_desc.count = 0;
	tcp_read_sock(sk, &rd_desc, iscsi_tcp_data_recv);

	read_unlock(&sk->sk_callback_lock);
}

static void
iscsi_tcp_state_change(struct sock *sk)
{
	struct iscsi_conn *conn;
	struct iscsi_session *session;
	void (*old_state_change)(struct sock *);

	read_lock(&sk->sk_callback_lock);

	conn = (struct iscsi_conn*)sk->sk_user_data;
	session = conn->session;

	if ((sk->sk_state == TCP_CLOSE_WAIT ||
	     sk->sk_state == TCP_CLOSE) &&
	    !atomic_read(&sk->sk_rmem_alloc)) {
		debug_tcp("iscsi_tcp_state_change: TCP_CLOSE|TCP_CLOSE_WAIT\n");
		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
	}

	old_state_change = conn->old_state_change;

	read_unlock(&sk->sk_callback_lock);

	old_state_change(sk);
}

/**
 * iscsi_write_space - Called when more output buffer space is available
 * @sk: socket space is available for
 **/
static void
iscsi_write_space(struct sock *sk)
{
	struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;
	conn->old_write_space(sk);
	debug_tcp("iscsi_write_space: cid %d\n", conn->id);
	clear_bit(SUSPEND_BIT, &conn->suspend_tx);
	schedule_work(&conn->xmitwork);
}

static void
iscsi_conn_set_callbacks(struct iscsi_conn *conn)
{
	struct sock *sk = conn->sock->sk;

	/* assign new callbacks */
	write_lock_bh(&sk->sk_callback_lock);
	sk->sk_user_data = conn;
	conn->old_data_ready = sk->sk_data_ready;
	conn->old_state_change = sk->sk_state_change;
	conn->old_write_space = sk->sk_write_space;
	sk->sk_data_ready = iscsi_tcp_data_ready;
	sk->sk_state_change = iscsi_tcp_state_change;
	sk->sk_write_space = iscsi_write_space;
	write_unlock_bh(&sk->sk_callback_lock);
}

static void
iscsi_conn_restore_callbacks(struct iscsi_conn *conn)
{
	struct sock *sk = conn->sock->sk;

	/* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
	write_lock_bh(&sk->sk_callback_lock);
	sk->sk_user_data    = NULL;
	sk->sk_data_ready   = conn->old_data_ready;
	sk->sk_state_change = conn->old_state_change;
	sk->sk_write_space  = conn->old_write_space;
	sk->sk_no_check	 = 0;
	write_unlock_bh(&sk->sk_callback_lock);
}

/**
 * iscsi_send - generic send routine
 * @sk: kernel's socket
 * @buf: buffer to write from
 * @size: actual size to write
 * @flags: socket's flags
 *
 * Notes:
 *	depending on buffer will use tcp_sendpage() or tcp_sendmsg().
 *	buf->sg.offset == -1 tells us that buffer is non S/G and forces
 *	to use tcp_sendmsg().
 */
static inline int
iscsi_send(struct socket *sk, struct iscsi_buf *buf, int size, int flags)
{
	int res;

	if ((int)buf->sg.offset >= 0) {
		int offset = buf->sg.offset + buf->sent;

		/* tcp_sendpage */
		res = sk->ops->sendpage(sk, buf->sg.page, offset, size, flags);
	} else {
		struct msghdr msg;

		buf->iov.iov_base = iscsi_buf_iov_base(buf);
		buf->iov.iov_len = size;

		memset(&msg, 0, sizeof(struct msghdr));

		/* tcp_sendmsg */
		res = kernel_sendmsg(sk, &msg, &buf->iov, 1, size);
	}

	return res;
}

/**
 * iscsi_sendhdr - send PDU Header via tcp_sendpage()
 * @conn: iscsi connection
 * @buf: buffer to write from
 * @datalen: lenght of data to be sent after the header
 *
 * Notes:
 *	(Tx, Fast Path)
 **/
static inline int
iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
{
	struct socket *sk = conn->sock;
	int flags = 0; /* MSG_DONTWAIT; */
	int res, size;

	size = buf->sg.length - buf->sent;
	BUG_ON(buf->sent + size > buf->sg.length);
	if (buf->sent + size != buf->sg.length || datalen)
		flags |= MSG_MORE;

	res = iscsi_send(sk, buf, size, flags);
	debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
	if (res >= 0) {
		conn->txdata_octets += res;
		buf->sent += res;
		if (size != res)
			return -EAGAIN;
		return 0;
	} else if (res == -EAGAIN) {
		conn->sendpage_failures_cnt++;
		set_bit(SUSPEND_BIT, &conn->suspend_tx);
	} else if (res == -EPIPE)
		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	return res;
}

/**
 * iscsi_sendpage - send one page of iSCSI Data-Out.
 * @conn: iscsi connection
 * @buf: buffer to write from
 * @count: remaining data
 * @sent: number of bytes sent
 *
 * Notes:
 *	(Tx, Fast Path)
 **/
static inline int
iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
	       int *count, int *sent)
{
	struct socket *sk = conn->sock;
	int flags = 0; /* MSG_DONTWAIT; */
	int res, size;

	size = buf->sg.length - buf->sent;
	BUG_ON(buf->sent + size > buf->sg.length);
	if (size > *count)
		size = *count;
	if (buf->sent + size != buf->sg.length || *count != size)
		flags |= MSG_MORE;

	res = iscsi_send(sk, buf, size, flags);
	debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
		  size, buf->sent, *count, *sent, res);
	if (res >= 0) {
		conn->txdata_octets += res;
		buf->sent += res;
		*count -= res;
		*sent += res;
		if (size != res)
			return -EAGAIN;
		return 0;
	} else if (res == -EAGAIN) {
		conn->sendpage_failures_cnt++;
		set_bit(SUSPEND_BIT, &conn->suspend_tx);
	} else if (res == -EPIPE)
		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	return res;
}

static inline void
iscsi_data_digest_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	BUG_ON(!conn->data_tx_tfm);
	crypto_digest_init(conn->data_tx_tfm);
	ctask->digest_count = 4;
}

static inline void
iscsi_buf_data_digest_update(struct iscsi_conn *conn, struct iscsi_buf *buf)
{
	struct scatterlist sg;

	if (buf->sg.offset != -1)
		crypto_digest_update(conn->data_tx_tfm, &buf->sg, 1);
	else {
		sg_init_one(&sg, (char *)buf->sg.page, buf->sg.length);
		crypto_digest_update(conn->data_tx_tfm, &sg, 1);
	}
}

static inline int
iscsi_digest_final_send(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
			struct iscsi_buf *buf, uint32_t *digest, int final)
{
	int rc = 0;
	int sent = 0;

	if (final)
		crypto_digest_final(conn->data_tx_tfm, (u8*)digest);

	iscsi_buf_init_virt(buf, (char*)digest, 4);
	rc = iscsi_sendpage(conn, buf, &ctask->digest_count, &sent);
	if (rc) {
		ctask->datadigest = *digest;
		ctask->xmstate |= XMSTATE_DATA_DIGEST;
	} else
		ctask->digest_count = 4;
	return rc;
}

/**
 * iscsi_solicit_data_cont - initialize next Data-Out
 * @conn: iscsi connection
 * @ctask: scsi command task
 * @r2t: R2T info
 * @left: bytes left to transfer
 *
 * Notes:
 *	Initialize next Data-Out within this R2T sequence and continue
 *	to process next Scatter-Gather element(if any) of this SCSI command.
 *
 *	Called under connection lock.
 **/
static void
iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
			struct iscsi_r2t_info *r2t, int left)
{
	struct iscsi_data *hdr;
	struct iscsi_data_task *dtask;
	struct scsi_cmnd *sc = ctask->sc;
	int new_offset;

	dtask = mempool_alloc(ctask->datapool, GFP_ATOMIC);
	BUG_ON(!dtask);
	hdr = &dtask->hdr;
	memset(hdr, 0, sizeof(struct iscsi_data));
	hdr->ttt = r2t->ttt;
	hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
	r2t->solicit_datasn++;
	hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
	memcpy(hdr->lun, ctask->hdr.lun, sizeof(hdr->lun));
	hdr->itt = ctask->hdr.itt;
	hdr->exp_statsn = r2t->exp_statsn;
	new_offset = r2t->data_offset + r2t->sent;
	hdr->offset = cpu_to_be32(new_offset);
	if (left > conn->max_xmit_dlength) {
		hton24(hdr->dlength, conn->max_xmit_dlength);
		r2t->data_count = conn->max_xmit_dlength;
	} else {
		hton24(hdr->dlength, left);
		r2t->data_count = left;
		hdr->flags = ISCSI_FLAG_CMD_FINAL;
	}
	conn->dataout_pdus_cnt++;

	iscsi_buf_init_virt(&r2t->headbuf, (char*)hdr,
			   sizeof(struct iscsi_hdr));

	r2t->dtask = dtask;

	if (sc->use_sg && !iscsi_buf_left(&r2t->sendbuf)) {
		BUG_ON(ctask->bad_sg == r2t->sg);
		iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
		r2t->sg += 1;
	} else
		iscsi_buf_init_iov(&ctask->sendbuf,
			    (char*)sc->request_buffer + new_offset,
			    r2t->data_count);

	list_add(&dtask->item, &ctask->dataqueue);
}

static void
iscsi_unsolicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_data *hdr;
	struct iscsi_data_task *dtask;

	dtask = mempool_alloc(ctask->datapool, GFP_ATOMIC);
	BUG_ON(!dtask);
	hdr = &dtask->hdr;
	memset(hdr, 0, sizeof(struct iscsi_data));
	hdr->ttt = cpu_to_be32(ISCSI_RESERVED_TAG);
	hdr->datasn = cpu_to_be32(ctask->unsol_datasn);
	ctask->unsol_datasn++;
	hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
	memcpy(hdr->lun, ctask->hdr.lun, sizeof(hdr->lun));
	hdr->itt = ctask->hdr.itt;
	hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
	hdr->offset = cpu_to_be32(ctask->total_length -
				  ctask->r2t_data_count -
				  ctask->unsol_count);
	if (ctask->unsol_count > conn->max_xmit_dlength) {
		hton24(hdr->dlength, conn->max_xmit_dlength);
		ctask->data_count = conn->max_xmit_dlength;
		hdr->flags = 0;
	} else {
		hton24(hdr->dlength, ctask->unsol_count);
		ctask->data_count = ctask->unsol_count;
		hdr->flags = ISCSI_FLAG_CMD_FINAL;
	}

	iscsi_buf_init_virt(&ctask->headbuf, (char*)hdr,
			   sizeof(struct iscsi_hdr));

	list_add(&dtask->item, &ctask->dataqueue);

	ctask->dtask = dtask;
}

/**
 * iscsi_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 * @conn: iscsi connection
 * @ctask: scsi command task
 * @sc: scsi command
 **/
static void
iscsi_cmd_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
		struct scsi_cmnd *sc)
{
	struct iscsi_session *session = conn->session;

	BUG_ON(__kfifo_len(ctask->r2tqueue));

	ctask->sc = sc;
	ctask->conn = conn;
	ctask->hdr.opcode = ISCSI_OP_SCSI_CMD;
	ctask->hdr.flags = ISCSI_ATTR_SIMPLE;
	int_to_scsilun(sc->device->lun, (struct scsi_lun *)ctask->hdr.lun);
	ctask->hdr.itt = ctask->itt | (conn->id << CID_SHIFT) |
			 (session->age << AGE_SHIFT);
	ctask->hdr.data_length = cpu_to_be32(sc->request_bufflen);
	ctask->hdr.cmdsn = cpu_to_be32(session->cmdsn); session->cmdsn++;
	ctask->hdr.exp_statsn = cpu_to_be32(conn->exp_statsn);
	memcpy(ctask->hdr.cdb, sc->cmnd, sc->cmd_len);
	memset(&ctask->hdr.cdb[sc->cmd_len], 0, MAX_COMMAND_SIZE - sc->cmd_len);

	ctask->mtask = NULL;
	ctask->sent = 0;
	ctask->sg_count = 0;

	ctask->total_length = sc->request_bufflen;

	if (sc->sc_data_direction == DMA_TO_DEVICE) {
		ctask->exp_r2tsn = 0;
		ctask->hdr.flags |= ISCSI_FLAG_CMD_WRITE;
		BUG_ON(ctask->total_length == 0);
		if (sc->use_sg) {
			struct scatterlist *sg = sc->request_buffer;

			iscsi_buf_init_sg(&ctask->sendbuf,
					  &sg[ctask->sg_count++]);
			ctask->sg = sg;
			ctask->bad_sg = sg + sc->use_sg;
		} else {
			iscsi_buf_init_iov(&ctask->sendbuf, sc->request_buffer,
					sc->request_bufflen);
		}

		/*
		 * Write counters:
		 *
		 *	imm_count	bytes to be sent right after
		 *			SCSI PDU Header
		 *
		 *	unsol_count	bytes(as Data-Out) to be sent
		 *			without	R2T ack right after
		 *			immediate data
		 *
		 *	r2t_data_count	bytes to be sent via R2T ack's
		 *
		 *      pad_count       bytes to be sent as zero-padding
		 */
		ctask->imm_count = 0;
		ctask->unsol_count = 0;
		ctask->unsol_datasn = 0;
		ctask->xmstate = XMSTATE_W_HDR;
		/* calculate write padding */
		ctask->pad_count = ctask->total_length & (ISCSI_PAD_LEN-1);
		if (ctask->pad_count) {
			ctask->pad_count = ISCSI_PAD_LEN - ctask->pad_count;
			debug_scsi("write padding %d bytes\n",
				ctask->pad_count);
			ctask->xmstate |= XMSTATE_W_PAD;
		}
		if (session->imm_data_en) {
			if (ctask->total_length >= session->first_burst)
				ctask->imm_count = min(session->first_burst,
							conn->max_xmit_dlength);
			else
				ctask->imm_count = min(ctask->total_length,
							conn->max_xmit_dlength);
			hton24(ctask->hdr.dlength, ctask->imm_count);
			ctask->xmstate |= XMSTATE_IMM_DATA;
		} else
			zero_data(ctask->hdr.dlength);

		if (!session->initial_r2t_en)
			ctask->unsol_count = min(session->first_burst,
				ctask->total_length) - ctask->imm_count;
		if (!ctask->unsol_count)
			/* No unsolicit Data-Out's */
			ctask->hdr.flags |= ISCSI_FLAG_CMD_FINAL;
		else
			ctask->xmstate |= XMSTATE_UNS_HDR | XMSTATE_UNS_INIT;

		ctask->r2t_data_count = ctask->total_length -
				    ctask->imm_count -
				    ctask->unsol_count;

		debug_scsi("cmd [itt %x total %d imm %d imm_data %d "
			   "r2t_data %d]\n",
			   ctask->itt, ctask->total_length, ctask->imm_count,
			   ctask->unsol_count, ctask->r2t_data_count);
	} else {
		ctask->hdr.flags |= ISCSI_FLAG_CMD_FINAL;
		if (sc->sc_data_direction == DMA_FROM_DEVICE)
			ctask->hdr.flags |= ISCSI_FLAG_CMD_READ;
		ctask->datasn = 0;
		ctask->xmstate = XMSTATE_R_HDR;
		zero_data(ctask->hdr.dlength);
	}

	iscsi_buf_init_virt(&ctask->headbuf, (char*)&ctask->hdr, 
			    sizeof(struct iscsi_hdr));
	conn->scsicmd_pdus_cnt++;
}

/**
 * iscsi_mtask_xmit - xmit management(immediate) task
 * @conn: iscsi connection
 * @mtask: task management task
 *
 * Notes:
 *	The function can return -EAGAIN in which case caller must
 *	call it again later, or recover. '0' return code means successful
 *	xmit.
 *
 *	Management xmit state machine consists of two states:
 *		IN_PROGRESS_IMM_HEAD - PDU Header xmit in progress
 *		IN_PROGRESS_IMM_DATA - PDU Data xmit in progress
 **/
static int
iscsi_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
{

	debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",
		conn->id, mtask->xmstate, mtask->itt);

	if (mtask->xmstate & XMSTATE_IMM_HDR) {
		mtask->xmstate &= ~XMSTATE_IMM_HDR;
		if (mtask->data_count)
			mtask->xmstate |= XMSTATE_IMM_DATA;
		if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
	    	    conn->stop_stage != STOP_CONN_RECOVER &&
		    conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &mtask->headbuf,
					(u8*)mtask->hdrext);
		if (iscsi_sendhdr(conn, &mtask->headbuf, mtask->data_count)) {
			mtask->xmstate |= XMSTATE_IMM_HDR;
			if (mtask->data_count)
				mtask->xmstate &= ~XMSTATE_IMM_DATA;
			return -EAGAIN;
		}
	}

	if (mtask->xmstate & XMSTATE_IMM_DATA) {
		BUG_ON(!mtask->data_count);
		mtask->xmstate &= ~XMSTATE_IMM_DATA;
		/* FIXME: implement.
		 * Virtual buffer could be spreaded across multiple pages...
		 */
		do {
			if (iscsi_sendpage(conn, &mtask->sendbuf,
				   &mtask->data_count, &mtask->sent)) {
				mtask->xmstate |= XMSTATE_IMM_DATA;
				return -EAGAIN;
			}
		} while (mtask->data_count);
	}

	BUG_ON(mtask->xmstate != XMSTATE_IDLE);
	return 0;
}

static inline int
handle_xmstate_r_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	ctask->xmstate &= ~XMSTATE_R_HDR;
	if (conn->hdrdgst_en) 
		iscsi_hdr_digest(conn, &ctask->headbuf, (u8*)ctask->hdrext);
	if (!iscsi_sendhdr(conn, &ctask->headbuf, 0)) {
		BUG_ON(ctask->xmstate != XMSTATE_IDLE);
		return 0; /* wait for Data-In */
	}
	ctask->xmstate |= XMSTATE_R_HDR;
	return -EAGAIN;
}

static inline int
handle_xmstate_w_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	ctask->xmstate &= ~XMSTATE_W_HDR;
	if (conn->hdrdgst_en) 
		iscsi_hdr_digest(conn, &ctask->headbuf, (u8*)ctask->hdrext);
	if (iscsi_sendhdr(conn, &ctask->headbuf, ctask->imm_count)) {
		ctask->xmstate |= XMSTATE_W_HDR;
		return -EAGAIN;
	}
	return 0;
}

static inline int
handle_xmstate_data_digest(struct iscsi_conn *conn,
			   struct iscsi_cmd_task *ctask)
{
	ctask->xmstate &= ~XMSTATE_DATA_DIGEST;
	debug_tcp("resent data digest 0x%x\n", ctask->datadigest);
	if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,
				    &ctask->datadigest, 0)) {
		ctask->xmstate |= XMSTATE_DATA_DIGEST;
		debug_tcp("resent data digest 0x%x fail!\n",
			  ctask->datadigest);
		return -EAGAIN;
	}
	return 0;
}

static inline int
handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	BUG_ON(!ctask->imm_count);
	ctask->xmstate &= ~XMSTATE_IMM_DATA;

	if (conn->datadgst_en) {
		iscsi_data_digest_init(conn, ctask);
		ctask->immdigest = 0;
	}

	for (;;) {
		if (iscsi_sendpage(conn, &ctask->sendbuf, &ctask->imm_count,
				   &ctask->sent)) {
			ctask->xmstate |= XMSTATE_IMM_DATA;
			if (conn->datadgst_en) {
				crypto_digest_final(conn->data_tx_tfm,
						(u8*)&ctask->immdigest);
				debug_tcp("tx imm sendpage fail 0x%x\n",
					  ctask->datadigest);
			}
			return -EAGAIN;
		}
		if (conn->datadgst_en)
			iscsi_buf_data_digest_update(conn, &ctask->sendbuf);

		if (!ctask->imm_count)
			break;
		iscsi_buf_init_sg(&ctask->sendbuf,
				  &ctask->sg[ctask->sg_count++]);
	}

	if (conn->datadgst_en && !(ctask->xmstate & XMSTATE_W_PAD)) {
		if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,
				            &ctask->immdigest, 1)) {
			debug_tcp("sending imm digest 0x%x fail!\n",
				  ctask->immdigest);
			return -EAGAIN;
		}
		debug_tcp("sending imm digest 0x%x\n", ctask->immdigest);
	}

	return 0;
}

static inline int
handle_xmstate_uns_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_data_task *dtask;

	ctask->xmstate |= XMSTATE_UNS_DATA;
	if (ctask->xmstate & XMSTATE_UNS_INIT) {
		iscsi_unsolicit_data_init(conn, ctask);
		BUG_ON(!ctask->dtask);
		dtask = ctask->dtask;
		if (conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &ctask->headbuf,
					(u8*)dtask->hdrext);
		ctask->xmstate &= ~XMSTATE_UNS_INIT;
	}
	if (iscsi_sendhdr(conn, &ctask->headbuf, ctask->data_count)) {
		ctask->xmstate &= ~XMSTATE_UNS_DATA;
		ctask->xmstate |= XMSTATE_UNS_HDR;
		return -EAGAIN;
	}

	debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
		   ctask->itt, ctask->unsol_count, ctask->sent);
	return 0;
}

static inline int
handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_data_task *dtask = ctask->dtask;

	BUG_ON(!ctask->data_count);
	ctask->xmstate &= ~XMSTATE_UNS_DATA;

	if (conn->datadgst_en) {
		iscsi_data_digest_init(conn, ctask);
		dtask->digest = 0;
	}

	for (;;) {
		int start = ctask->sent;

		if (iscsi_sendpage(conn, &ctask->sendbuf, &ctask->data_count,
				   &ctask->sent)) {
			ctask->unsol_count -= ctask->sent - start;
			ctask->xmstate |= XMSTATE_UNS_DATA;
			/* will continue with this ctask later.. */
			if (conn->datadgst_en) {
				crypto_digest_final(conn->data_tx_tfm,
						(u8 *)&dtask->digest);
				debug_tcp("tx uns data fail 0x%x\n",
					  dtask->digest);
			}
			return -EAGAIN;
		}

		BUG_ON(ctask->sent > ctask->total_length);
		ctask->unsol_count -= ctask->sent - start;

		/*
		 * XXX:we may run here with un-initial sendbuf.
		 * so pass it
		 */
		if (conn->datadgst_en && ctask->sent - start > 0)
			iscsi_buf_data_digest_update(conn, &ctask->sendbuf);

		if (!ctask->data_count)
			break;
		iscsi_buf_init_sg(&ctask->sendbuf,
				  &ctask->sg[ctask->sg_count++]);
	}
	BUG_ON(ctask->unsol_count < 0);

	/*
	 * Done with the Data-Out. Next, check if we need
	 * to send another unsolicited Data-Out.
	 */
	if (ctask->unsol_count) {
		if (conn->datadgst_en) {
			if (iscsi_digest_final_send(conn, ctask,
						    &dtask->digestbuf,
						    &dtask->digest, 1)) {
				debug_tcp("send uns digest 0x%x fail\n",
					  dtask->digest);
				return -EAGAIN;
			}
			debug_tcp("sending uns digest 0x%x, more uns\n",
				  dtask->digest);
		}
		ctask->xmstate |= XMSTATE_UNS_INIT;
		return 1;
	}

	if (conn->datadgst_en && !(ctask->xmstate & XMSTATE_W_PAD)) {
		if (iscsi_digest_final_send(conn, ctask,
					    &dtask->digestbuf,
					    &dtask->digest, 1)) {
			debug_tcp("send last uns digest 0x%x fail\n",
				   dtask->digest);
			return -EAGAIN;
		}
		debug_tcp("sending uns digest 0x%x\n",dtask->digest);
	}

	return 0;
}

static inline int
handle_xmstate_sol_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_session *session = conn->session;
	struct iscsi_r2t_info *r2t = ctask->r2t;
	struct iscsi_data_task *dtask = r2t->dtask;
	int left;

	ctask->xmstate &= ~XMSTATE_SOL_DATA;
	ctask->dtask = dtask;

	if (conn->datadgst_en) {
		iscsi_data_digest_init(conn, ctask);
		dtask->digest = 0;
	}
solicit_again:
	/*
	 * send Data-Out whitnin this R2T sequence.
	 */
	if (!r2t->data_count)
		goto data_out_done;

	if (iscsi_sendpage(conn, &r2t->sendbuf, &r2t->data_count, &r2t->sent)) {
		ctask->xmstate |= XMSTATE_SOL_DATA;
		/* will continue with this ctask later.. */
		if (conn->datadgst_en) {
			crypto_digest_final(conn->data_tx_tfm,
					  (u8 *)&dtask->digest);
			debug_tcp("r2t data send fail 0x%x\n", dtask->digest);
		}
		return -EAGAIN;
	}

	BUG_ON(r2t->data_count < 0);
	if (conn->datadgst_en)
		iscsi_buf_data_digest_update(conn, &r2t->sendbuf);

	if (r2t->data_count) {
		BUG_ON(ctask->sc->use_sg == 0);
		if (!iscsi_buf_left(&r2t->sendbuf)) {
			BUG_ON(ctask->bad_sg == r2t->sg);
			iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
			r2t->sg += 1;
		}
		goto solicit_again;
	}

data_out_done:
	/*
	 * Done with this Data-Out. Next, check if we have
	 * to send another Data-Out for this R2T.
	 */
	BUG_ON(r2t->data_length - r2t->sent < 0);
	left = r2t->data_length - r2t->sent;
	if (left) {
		if (conn->datadgst_en) {
			if (iscsi_digest_final_send(conn, ctask,
						    &dtask->digestbuf,
						    &dtask->digest, 1)) {
				debug_tcp("send r2t data digest 0x%x"
					  "fail\n", dtask->digest);
				return -EAGAIN;
			}
			debug_tcp("r2t data send digest 0x%x\n",
				  dtask->digest);
		}
		iscsi_solicit_data_cont(conn, ctask, r2t, left);
		ctask->xmstate |= XMSTATE_SOL_DATA;
		ctask->xmstate &= ~XMSTATE_SOL_HDR;
		return 1;
	}

	/*
	 * Done with this R2T. Check if there are more
	 * outstanding R2Ts ready to be processed.
	 */
	BUG_ON(ctask->r2t_data_count - r2t->data_length < 0);
	if (conn->datadgst_en) {
		if (iscsi_digest_final_send(conn, ctask, &dtask->digestbuf,
					    &dtask->digest, 1)) {
			debug_tcp("send last r2t data digest 0x%x"
				  "fail\n", dtask->digest);
			return -EAGAIN;
		}
		debug_tcp("r2t done dout digest 0x%x\n", dtask->digest);
	}

	ctask->r2t_data_count -= r2t->data_length;
	ctask->r2t = NULL;
	spin_lock_bh(&session->lock);
	__kfifo_put(ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
	spin_unlock_bh(&session->lock);
	if (__kfifo_get(ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
		ctask->r2t = r2t;
		ctask->xmstate |= XMSTATE_SOL_DATA;
		ctask->xmstate &= ~XMSTATE_SOL_HDR;
		return 1;
	}

	return 0;
}

static inline int
handle_xmstate_w_pad(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_data_task *dtask = ctask->dtask;
	int sent;

	ctask->xmstate &= ~XMSTATE_W_PAD;
	iscsi_buf_init_virt(&ctask->sendbuf, (char*)&ctask->pad,
			    ctask->pad_count);
	if (iscsi_sendpage(conn, &ctask->sendbuf, &ctask->pad_count, &sent)) {
		ctask->xmstate |= XMSTATE_W_PAD;
		return -EAGAIN;
	}

	if (conn->datadgst_en) {
		iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
		/* imm data? */
		if (!dtask) {
			if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,
						    &ctask->immdigest, 1)) {
				debug_tcp("send padding digest 0x%x"
					  "fail!\n", ctask->immdigest);
				return -EAGAIN;
			}
			debug_tcp("done with padding, digest 0x%x\n",
				  ctask->datadigest);
		} else {
			if (iscsi_digest_final_send(conn, ctask,
						    &dtask->digestbuf,
						    &dtask->digest, 1)) {
				debug_tcp("send padding digest 0x%x"
				          "fail\n", dtask->digest);
				return -EAGAIN;
			}
			debug_tcp("done with padding, digest 0x%x\n",
				  dtask->digest);
		}
	}

	return 0;
}

static int
iscsi_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	int rc = 0;

	debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
		conn->id, ctask->xmstate, ctask->itt);

	/*
	 * serialize with TMF AbortTask
	 */
	if (ctask->mtask)
		return rc;

	if (ctask->xmstate & XMSTATE_R_HDR) {
		rc = handle_xmstate_r_hdr(conn, ctask);
		return rc;
	}

	if (ctask->xmstate & XMSTATE_W_HDR) {
		rc = handle_xmstate_w_hdr(conn, ctask);
		if (rc)
			return rc;
	}

	/* XXX: for data digest xmit recover */
	if (ctask->xmstate & XMSTATE_DATA_DIGEST) {
		rc = handle_xmstate_data_digest(conn, ctask);
		if (rc)
			return rc;
	}

	if (ctask->xmstate & XMSTATE_IMM_DATA) {
		rc = handle_xmstate_imm_data(conn, ctask);
		if (rc)
			return rc;
	}

	if (ctask->xmstate & XMSTATE_UNS_HDR) {
		BUG_ON(!ctask->unsol_count);
		ctask->xmstate &= ~XMSTATE_UNS_HDR;
unsolicit_head_again:
		rc = handle_xmstate_uns_hdr(conn, ctask);
		if (rc)
			return rc;
	}

	if (ctask->xmstate & XMSTATE_UNS_DATA) {
		rc = handle_xmstate_uns_data(conn, ctask);
		if (rc == 1)
			goto unsolicit_head_again;
		else if (rc)
			return rc;
		goto done;
	}

	if (ctask->xmstate & XMSTATE_SOL_HDR) {
		struct iscsi_r2t_info *r2t;

		ctask->xmstate &= ~XMSTATE_SOL_HDR;
		ctask->xmstate |= XMSTATE_SOL_DATA;
		if (!ctask->r2t)
			__kfifo_get(ctask->r2tqueue, (void*)&ctask->r2t,
				    sizeof(void*));
solicit_head_again:
		r2t = ctask->r2t;
		if (conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &r2t->headbuf, 
					(u8*)r2t->dtask->hdrext);
		if (iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count)) {
			ctask->xmstate &= ~XMSTATE_SOL_DATA;
			ctask->xmstate |= XMSTATE_SOL_HDR;
			return -EAGAIN;
		}

		debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
			r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
			r2t->sent);
	}

	if (ctask->xmstate & XMSTATE_SOL_DATA) {
		rc = handle_xmstate_sol_data(conn, ctask);
		if (rc == 1)
			goto solicit_head_again;
		if (rc)
			return rc;
	}

done:
	/*
	 * Last thing to check is whether we need to send write
	 * padding. Note that we check for xmstate equality, not just the bit.
	 */
	if (ctask->xmstate == XMSTATE_W_PAD)
		rc = handle_xmstate_w_pad(conn, ctask);

	return rc;
}

/**
 * iscsi_data_xmit - xmit any command into the scheduled connection
 * @conn: iscsi connection
 *
 * Notes:
 *	The function can return -EAGAIN in which case the caller must
 *	re-schedule it again later or recover. '0' return code means
 *	successful xmit.
 **/
static int
iscsi_data_xmit(struct iscsi_conn *conn)
{
	if (unlikely(conn->suspend_tx)) {
		debug_tcp("conn %d Tx suspended!\n", conn->id);
		return 0;
	}

	/*
	 * Transmit in the following order:
	 *
	 * 1) un-finished xmit (ctask or mtask)
	 * 2) immediate control PDUs
	 * 3) write data
	 * 4) SCSI commands
	 * 5) non-immediate control PDUs
	 *
	 * No need to lock around __kfifo_get as long as
	 * there's one producer and one consumer.
	 */

	BUG_ON(conn->ctask && conn->mtask);

	if (conn->ctask) {
		if (iscsi_ctask_xmit(conn, conn->ctask))
			goto again;
		/* done with this in-progress ctask */
		conn->ctask = NULL;
	}
	if (conn->mtask) {
	        if (iscsi_mtask_xmit(conn, conn->mtask))
		        goto again;
		/* done with this in-progress mtask */
		conn->mtask = NULL;
	}

	/* process immediate first */
        if (unlikely(__kfifo_len(conn->immqueue))) {
		struct iscsi_session *session = conn->session;
	        while (__kfifo_get(conn->immqueue, (void*)&conn->mtask,
			           sizeof(void*))) {
		        if (iscsi_mtask_xmit(conn, conn->mtask))
			        goto again;

		        if (conn->mtask->hdr.itt ==
					cpu_to_be32(ISCSI_RESERVED_TAG)) {
			        spin_lock_bh(&session->lock);
			        __kfifo_put(session->mgmtpool.queue,
					    (void*)&conn->mtask, sizeof(void*));
			        spin_unlock_bh(&session->lock);
		        }
	        }
		/* done with this mtask */
		conn->mtask = NULL;
	}

	/* process write queue */
	while (__kfifo_get(conn->writequeue, (void*)&conn->ctask,
			   sizeof(void*))) {
		if (iscsi_ctask_xmit(conn, conn->ctask))
			goto again;
	}

	/* process command queue */
	while (__kfifo_get(conn->xmitqueue, (void*)&conn->ctask,
			   sizeof(void*))) {
		if (iscsi_ctask_xmit(conn, conn->ctask))
			goto again;
	}
	/* done with this ctask */
	conn->ctask = NULL;

	/* process the rest control plane PDUs, if any */
        if (unlikely(__kfifo_len(conn->mgmtqueue))) {
		struct iscsi_session *session = conn->session;

	        while (__kfifo_get(conn->mgmtqueue, (void*)&conn->mtask,
			           sizeof(void*))) {
		        if (iscsi_mtask_xmit(conn, conn->mtask))
			        goto again;

		        if (conn->mtask->hdr.itt ==
					cpu_to_be32(ISCSI_RESERVED_TAG)) {
			        spin_lock_bh(&session->lock);
			        __kfifo_put(session->mgmtpool.queue,
					    (void*)&conn->mtask,
				            sizeof(void*));
			        spin_unlock_bh(&session->lock);
		        }
	        }
		/* done with this mtask */
		conn->mtask = NULL;
	}

	return 0;

again:
	if (unlikely(conn->suspend_tx))
		return 0;

	return -EAGAIN;
}

static void
iscsi_xmitworker(void *data)
{
	struct iscsi_conn *conn = data;

	/*
	 * serialize Xmit worker on a per-connection basis.
	 */
	down(&conn->xmitsema);
	if (iscsi_data_xmit(conn))
		schedule_work(&conn->xmitwork);
	up(&conn->xmitsema);
}

#define FAILURE_BAD_HOST		1
#define FAILURE_SESSION_FAILED		2
#define FAILURE_SESSION_FREED		3
#define FAILURE_WINDOW_CLOSED		4
#define FAILURE_SESSION_TERMINATE	5

static int
iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
{
	struct Scsi_Host *host;
	int reason = 0;
	struct iscsi_session *session;
	struct iscsi_conn *conn = NULL;
	struct iscsi_cmd_task *ctask = NULL;

	sc->scsi_done = done;
	sc->result = 0;

	host = sc->device->host;
	session = iscsi_hostdata(host->hostdata);
	BUG_ON(host != session->host);

	spin_lock(&session->lock);

	if (session->state != ISCSI_STATE_LOGGED_IN) {
		if (session->state == ISCSI_STATE_FAILED) {
			reason = FAILURE_SESSION_FAILED;
			goto reject;
		} else if (session->state == ISCSI_STATE_TERMINATE) {
			reason = FAILURE_SESSION_TERMINATE;
			goto fault;
		}
		reason = FAILURE_SESSION_FREED;
		goto fault;
	}

	/*
	 * Check for iSCSI window and take care of CmdSN wrap-around
	 */
	if ((int)(session->max_cmdsn - session->cmdsn) < 0) {
		reason = FAILURE_WINDOW_CLOSED;
		goto reject;
	}

	conn = session->leadconn;

	__kfifo_get(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
	BUG_ON(ctask->sc);

	sc->SCp.phase = session->age;
	sc->SCp.ptr = (char*)ctask;
	iscsi_cmd_init(conn, ctask, sc);

	__kfifo_put(conn->xmitqueue, (void*)&ctask, sizeof(void*));
	debug_scsi(
	       "ctask enq [%s cid %d sc %lx itt 0x%x len %d cmdsn %d win %d]\n",
		sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
		conn->id, (long)sc, ctask->itt, sc->request_bufflen,
		session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);
	spin_unlock(&session->lock);

        if (!in_interrupt() && !down_trylock(&conn->xmitsema)) {
		spin_unlock_irq(host->host_lock);
		if (iscsi_data_xmit(conn))
			schedule_work(&conn->xmitwork);
		up(&conn->xmitsema);
		spin_lock_irq(host->host_lock);
	} else
		schedule_work(&conn->xmitwork);

	return 0;

reject:
	spin_unlock(&session->lock);
	debug_scsi("cmd 0x%x rejected (%d)\n", sc->cmnd[0], reason);
	return SCSI_MLQUEUE_HOST_BUSY;

fault:
	spin_unlock(&session->lock);
	printk(KERN_ERR "iscsi_tcp: cmd 0x%x is not queued (%d)\n",
	       sc->cmnd[0], reason);
	sc->sense_buffer[0] = 0x70;
	sc->sense_buffer[2] = NOT_READY;
	sc->sense_buffer[7] = 0x6;
	sc->sense_buffer[12] = 0x08;
	sc->sense_buffer[13] = 0x00;
	sc->result = (DID_NO_CONNECT << 16);
	sc->resid = sc->request_bufflen;
	sc->scsi_done(sc);
	return 0;
}

static int
iscsi_change_queue_depth(struct scsi_device *sdev, int depth)
{
	if (depth > ISCSI_MAX_CMD_PER_LUN)
		depth = ISCSI_MAX_CMD_PER_LUN;
	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
	return sdev->queue_depth;
}

static int
iscsi_pool_init(struct iscsi_queue *q, int max, void ***items, int item_size)
{
	int i;

	*items = kmalloc(max * sizeof(void*), GFP_KERNEL);
	if (*items == NULL)
		return -ENOMEM;

	q->max = max;
	q->pool = kmalloc(max * sizeof(void*), GFP_KERNEL);
	if (q->pool == NULL) {
		kfree(*items);
		return -ENOMEM;
	}

	q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
			      GFP_KERNEL, NULL);
	if (q->queue == ERR_PTR(-ENOMEM)) {
		kfree(q->pool);
		kfree(*items);
		return -ENOMEM;
	}

	for (i = 0; i < max; i++) {
		q->pool[i] = kmalloc(item_size, GFP_KERNEL);
		if (q->pool[i] == NULL) {
			int j;

			for (j = 0; j < i; j++)
				kfree(q->pool[j]);

			kfifo_free(q->queue);
			kfree(q->pool);
			kfree(*items);
			return -ENOMEM;
		}
		memset(q->pool[i], 0, item_size);
		(*items)[i] = q->pool[i];
		__kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
	}
	return 0;
}

static void
iscsi_pool_free(struct iscsi_queue *q, void **items)
{
	int i;

	for (i = 0; i < q->max; i++)
		kfree(items[i]);
	kfree(q->pool);
	kfree(items);
}

static iscsi_connh_t
iscsi_conn_create(iscsi_sessionh_t sessionh, uint32_t conn_idx)
{
	struct iscsi_session *session = iscsi_ptr(sessionh);
	struct iscsi_conn *conn = NULL;

	conn = kmalloc(sizeof(struct iscsi_conn), GFP_KERNEL);
	if (conn == NULL)
		goto conn_alloc_fail;
	memset(conn, 0, sizeof(struct iscsi_conn));

	conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
	conn->in_progress = IN_PROGRESS_WAIT_HEADER;
	conn->id = conn_idx;
	conn->exp_statsn = 0;
	conn->tmabort_state = TMABORT_INITIAL;

	/* initial operational parameters */
	conn->hdr_size = sizeof(struct iscsi_hdr);
	conn->data_size = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;
	conn->max_recv_dlength = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;

	spin_lock_init(&conn->lock);

	/* initialize general xmit PDU commands queue */
	conn->xmitqueue = kfifo_alloc(session->cmds_max * sizeof(void*),
					GFP_KERNEL, NULL);
	if (conn->xmitqueue == ERR_PTR(-ENOMEM))
		goto xmitqueue_alloc_fail;

	/* initialize write response PDU commands queue */
	conn->writequeue = kfifo_alloc(session->cmds_max * sizeof(void*),
					GFP_KERNEL, NULL);
	if (conn->writequeue == ERR_PTR(-ENOMEM))
		goto writequeue_alloc_fail;

	/* initialize general immediate & non-immediate PDU commands queue */
	conn->immqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
			                GFP_KERNEL, NULL);
	if (conn->immqueue == ERR_PTR(-ENOMEM))
		goto immqueue_alloc_fail;

	conn->mgmtqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
			                GFP_KERNEL, NULL);
	if (conn->mgmtqueue == ERR_PTR(-ENOMEM))
		goto mgmtqueue_alloc_fail;

	INIT_WORK(&conn->xmitwork, iscsi_xmitworker, conn);

	/* allocate login_mtask used for the login/text sequences */
	spin_lock_bh(&session->lock);
	if (!__kfifo_get(session->mgmtpool.queue,
                         (void*)&conn->login_mtask,
			 sizeof(void*))) {
		spin_unlock_bh(&session->lock);
		goto login_mtask_alloc_fail;
	}
	spin_unlock_bh(&session->lock);

	/* allocate initial PDU receive place holder */
	if (conn->data_size <= PAGE_SIZE)
		conn->data = kmalloc(conn->data_size, GFP_KERNEL);
	else
		conn->data = (void*)__get_free_pages(GFP_KERNEL,
					get_order(conn->data_size));
	if (!conn->data)
		goto max_recv_dlenght_alloc_fail;

	init_timer(&conn->tmabort_timer);
	init_MUTEX(&conn->xmitsema);
	init_waitqueue_head(&conn->ehwait);

	return iscsi_handle(conn);

max_recv_dlenght_alloc_fail:
	spin_lock_bh(&session->lock);
	__kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
		    sizeof(void*));
	spin_unlock_bh(&session->lock);
login_mtask_alloc_fail:
	kfifo_free(conn->mgmtqueue);
mgmtqueue_alloc_fail:
	kfifo_free(conn->immqueue);
immqueue_alloc_fail:
	kfifo_free(conn->writequeue);
writequeue_alloc_fail:
	kfifo_free(conn->xmitqueue);
xmitqueue_alloc_fail:
	kfree(conn);
conn_alloc_fail:
	return iscsi_handle(NULL);
}

static void
iscsi_conn_destroy(iscsi_connh_t connh)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);
	struct iscsi_session *session = conn->session;

	down(&conn->xmitsema);
	set_bit(SUSPEND_BIT, &conn->suspend_tx);
	if (conn->c_stage == ISCSI_CONN_INITIAL_STAGE && conn->sock) {
		struct sock *sk = conn->sock->sk;

		/*
		 * conn_start() has never been called!
		 * need to cleanup the socket.
		 */
		write_lock_bh(&sk->sk_callback_lock);
		set_bit(SUSPEND_BIT, &conn->suspend_rx);
		write_unlock_bh(&sk->sk_callback_lock);

		sock_hold(conn->sock->sk);
		iscsi_conn_restore_callbacks(conn);
		sock_put(conn->sock->sk);
		sock_release(conn->sock);
		conn->sock = NULL;
	}

	spin_lock_bh(&session->lock);
	conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
	if (session->leadconn == conn) {
		/*
		 * leading connection? then give up on recovery.
		 */
		session->state = ISCSI_STATE_TERMINATE;
		wake_up(&conn->ehwait);
	}
	spin_unlock_bh(&session->lock);

	up(&conn->xmitsema);

	/*
	 * Block until all in-progress commands for this connection
	 * time out or fail.
	 */
	for (;;) {
		spin_lock_bh(&conn->lock);
		if (!session->host->host_busy) { /* OK for ERL == 0 */
			spin_unlock_bh(&conn->lock);
			break;
		}
		spin_unlock_bh(&conn->lock);
		msleep_interruptible(500);
		printk("conn_destroy(): host_busy %d host_failed %d\n",
			session->host->host_busy, session->host->host_failed);
		/*
		 * force eh_abort() to unblock
		 */
		wake_up(&conn->ehwait);
	}

	/* now free crypto */
	if (conn->hdrdgst_en || conn->datadgst_en) {
		if (conn->tx_tfm)
			crypto_free_tfm(conn->tx_tfm);
		if (conn->rx_tfm)
			crypto_free_tfm(conn->rx_tfm);
		if (conn->data_tx_tfm)
			crypto_free_tfm(conn->data_tx_tfm);
		if (conn->data_rx_tfm)
			crypto_free_tfm(conn->data_rx_tfm);
	}

	/* free conn->data, size = MaxRecvDataSegmentLength */
	if (conn->data_size <= PAGE_SIZE)
		kfree(conn->data);
	else
		free_pages((unsigned long)conn->data,
					get_order(conn->data_size));

	spin_lock_bh(&session->lock);
	__kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
		    sizeof(void*));
	list_del(&conn->item);
	if (list_empty(&session->connections))
		session->leadconn = NULL;
	if (session->leadconn && session->leadconn == conn)
		session->leadconn = container_of(session->connections.next,
			struct iscsi_conn, item);

	if (session->leadconn == NULL)
		/* none connections exits.. reset sequencing */
		session->cmdsn = session->max_cmdsn = session->exp_cmdsn = 1;
	spin_unlock_bh(&session->lock);

	kfifo_free(conn->xmitqueue);
	kfifo_free(conn->writequeue);
	kfifo_free(conn->immqueue);
	kfifo_free(conn->mgmtqueue);
	kfree(conn);
}

static int
iscsi_conn_bind(iscsi_sessionh_t sessionh, iscsi_connh_t connh,
		uint32_t transport_fd, int is_leading)
{
	struct iscsi_session *session = iscsi_ptr(sessionh);
	struct iscsi_conn *tmp = ERR_PTR(-EEXIST), *conn = iscsi_ptr(connh);
	struct sock *sk;
	struct socket *sock;
	int err;

	/* lookup for existing socket */
	sock = sockfd_lookup(transport_fd, &err);
	if (!sock) {
		printk(KERN_ERR "iscsi_tcp: sockfd_lookup failed %d\n", err);
		return -EEXIST;
	}

	/* lookup for existing connection */
	spin_lock_bh(&session->lock);
	list_for_each_entry(tmp, &session->connections, item) {
		if (tmp == conn) {
			if (conn->c_stage != ISCSI_CONN_STOPPED ||
			    conn->stop_stage == STOP_CONN_TERM) {
				printk(KERN_ERR "iscsi_tcp: can't bind "
				       "non-stopped connection (%d:%d)\n",
				       conn->c_stage, conn->stop_stage);
				spin_unlock_bh(&session->lock);
				return -EIO;
			}
			break;
		}
	}
	if (tmp != conn) {
		/* bind new iSCSI connection to session */
		conn->session = session;

		list_add(&conn->item, &session->connections);
	}
	spin_unlock_bh(&session->lock);

	if (conn->stop_stage != STOP_CONN_SUSPEND) {
		/* bind iSCSI connection and socket */
		conn->sock = sock;

		/* setup Socket parameters */
		sk = sock->sk;
		sk->sk_reuse = 1;
		sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
		sk->sk_allocation = GFP_ATOMIC;

		/* FIXME: disable Nagle's algorithm */

		/*
		 * Intercept TCP callbacks for sendfile like receive
		 * processing.
		 */
		iscsi_conn_set_callbacks(conn);

		/*
		 * set receive state machine into initial state
		 */
		conn->in_progress = IN_PROGRESS_WAIT_HEADER;
	}

	if (is_leading)
		session->leadconn = conn;

	/*
	 * Unblock xmitworker(), Login Phase will pass through.
	 */
	clear_bit(SUSPEND_BIT, &conn->suspend_rx);
	clear_bit(SUSPEND_BIT, &conn->suspend_tx);

	return 0;
}

static int
iscsi_conn_start(iscsi_connh_t connh)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);
	struct iscsi_session *session = conn->session;
	struct sock *sk;

	/* FF phase warming up... */

	if (session == NULL) {
		printk(KERN_ERR "iscsi_tcp: can't start unbound connection\n");
		return -EPERM;
	}

	sk = conn->sock->sk;

	write_lock_bh(&sk->sk_callback_lock);
	spin_lock_bh(&session->lock);
	conn->c_stage = ISCSI_CONN_STARTED;
	session->state = ISCSI_STATE_LOGGED_IN;

	switch(conn->stop_stage) {
	case STOP_CONN_RECOVER:
		/*
		 * unblock eh_abort() if it is blocked. re-try all
		 * commands after successful recovery
		 */
		session->conn_cnt++;
		conn->stop_stage = 0;
		conn->tmabort_state = TMABORT_INITIAL;
		session->age++;
		wake_up(&conn->ehwait);
		break;
	case STOP_CONN_TERM:
		session->conn_cnt++;
		conn->stop_stage = 0;
		break;
	case STOP_CONN_SUSPEND:
		conn->stop_stage = 0;
		clear_bit(SUSPEND_BIT, &conn->suspend_rx);
		clear_bit(SUSPEND_BIT, &conn->suspend_tx);
		break;
	default:
		break;
	}
	spin_unlock_bh(&session->lock);
	write_unlock_bh(&sk->sk_callback_lock);

	return 0;
}

static void
iscsi_conn_stop(iscsi_connh_t connh, int flag)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);
	struct iscsi_session *session = conn->session;
	struct sock *sk;
	unsigned long flags;

	BUG_ON(!conn->sock);
	sk = conn->sock->sk;
	write_lock_bh(&sk->sk_callback_lock);
	set_bit(SUSPEND_BIT, &conn->suspend_rx);
	write_unlock_bh(&sk->sk_callback_lock);

	down(&conn->xmitsema);

	spin_lock_irqsave(session->host->host_lock, flags);
	spin_lock(&session->lock);
	conn->stop_stage = flag;
	conn->c_stage = ISCSI_CONN_STOPPED;
	set_bit(SUSPEND_BIT, &conn->suspend_tx);

	if (flag != STOP_CONN_SUSPEND)
		session->conn_cnt--;

	if (session->conn_cnt == 0 || session->leadconn == conn)
		session->state = ISCSI_STATE_FAILED;

	spin_unlock(&session->lock);
	spin_unlock_irqrestore(session->host->host_lock, flags);

	if (flag == STOP_CONN_TERM || flag == STOP_CONN_RECOVER) {
		struct iscsi_cmd_task *ctask;
		struct iscsi_mgmt_task *mtask;

		/*
		 * Socket must go now.
		 */
		sock_hold(conn->sock->sk);
		iscsi_conn_restore_callbacks(conn);
		sock_put(conn->sock->sk);

		/*
		 * flush xmit queues.
		 */
		spin_lock_bh(&session->lock);
		while (__kfifo_get(conn->writequeue, (void*)&ctask,
			    sizeof(void*)) ||
			__kfifo_get(conn->xmitqueue, (void*)&ctask,
			    sizeof(void*))) {
			struct iscsi_r2t_info *r2t;

			/*
			 * flush ctask's r2t queues
			 */
			while (__kfifo_get(ctask->r2tqueue, (void*)&r2t,
				sizeof(void*)))
				__kfifo_put(ctask->r2tpool.queue, (void*)&r2t,
					    sizeof(void*));

			spin_unlock_bh(&session->lock);
			local_bh_disable();
			iscsi_ctask_cleanup(conn, ctask);
			local_bh_enable();
			spin_lock_bh(&session->lock);
		}
		conn->ctask = NULL;
		while (__kfifo_get(conn->immqueue, (void*)&mtask,
			   sizeof(void*)) ||
			__kfifo_get(conn->mgmtqueue, (void*)&mtask,
			   sizeof(void*))) {
			__kfifo_put(session->mgmtpool.queue,
				    (void*)&mtask, sizeof(void*));
		}
		conn->mtask = NULL;
		spin_unlock_bh(&session->lock);

		/*
		 * release socket only after we stopped data_xmit()
		 * activity and flushed all outstandings
		 */
		sock_release(conn->sock);
		conn->sock = NULL;

		/*
		 * for connection level recovery we should not calculate
		 * header digest. conn->hdr_size used for optimization
		 * in hdr_extract() and will be re-negotiated at
		 * set_param() time.
		 */
		if (flag == STOP_CONN_RECOVER) {
			conn->hdr_size = sizeof(struct iscsi_hdr);
			conn->hdrdgst_en = 0;
			conn->datadgst_en = 0;
		}
	}
	up(&conn->xmitsema);
}

static int
iscsi_conn_send_generic(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
			char *data, uint32_t data_size)
{
	struct iscsi_session *session = conn->session;
	struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;
	struct iscsi_mgmt_task *mtask;

	spin_lock_bh(&session->lock);
	if (session->state == ISCSI_STATE_TERMINATE) {
		spin_unlock_bh(&session->lock);
		return -EPERM;
	}
	if (hdr->opcode == (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) ||
	    hdr->opcode == (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
		/*
		 * Login and Text are sent serially, in
		 * request-followed-by-response sequence.
		 * Same mtask can be used. Same ITT must be used.
		 * Note that login_mtask is preallocated at conn_create().
		 */
		mtask = conn->login_mtask;
	else {
	        BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
	        BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);

		if (!__kfifo_get(session->mgmtpool.queue,
				 (void*)&mtask, sizeof(void*))) {
			spin_unlock_bh(&session->lock);
			return -ENOSPC;
		}
	}

	/*
	 * pre-format CmdSN and ExpStatSN for outgoing PDU.
	 */
	if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG)) {
		hdr->itt = mtask->itt | (conn->id << CID_SHIFT) |
			   (session->age << AGE_SHIFT);
		nop->cmdsn = cpu_to_be32(session->cmdsn);
		if (conn->c_stage == ISCSI_CONN_STARTED &&
		    !(hdr->opcode & ISCSI_OP_IMMEDIATE))
			session->cmdsn++;
	} else
		/* do not advance CmdSN */
		nop->cmdsn = cpu_to_be32(session->cmdsn);

	nop->exp_statsn = cpu_to_be32(conn->exp_statsn);

	memcpy(&mtask->hdr, hdr, sizeof(struct iscsi_hdr));

	iscsi_buf_init_virt(&mtask->headbuf, (char*)&mtask->hdr,
				    sizeof(struct iscsi_hdr));

	spin_unlock_bh(&session->lock);

	if (data_size) {
		memcpy(mtask->data, data, data_size);
		mtask->data_count = data_size;
	} else
		mtask->data_count = 0;

	mtask->xmstate = XMSTATE_IMM_HDR;

	if (mtask->data_count) {
		iscsi_buf_init_iov(&mtask->sendbuf, (char*)mtask->data,
				    mtask->data_count);
	}

	debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",
		   hdr->opcode, hdr->itt, data_size);

	/*
	 * since send_pdu() could be called at least from two contexts,
	 * we need to serialize __kfifo_put, so we don't have to take
	 * additional lock on fast data-path
	 */
        if (hdr->opcode & ISCSI_OP_IMMEDIATE)
	        __kfifo_put(conn->immqueue, (void*)&mtask, sizeof(void*));
	else
	        __kfifo_put(conn->mgmtqueue, (void*)&mtask, sizeof(void*));

	schedule_work(&conn->xmitwork);

	return 0;
}

static int
iscsi_eh_host_reset(struct scsi_cmnd *sc)
{
	struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
	struct iscsi_conn *conn = ctask->conn;
	struct iscsi_session *session = conn->session;

	spin_lock_bh(&session->lock);
	if (session->state == ISCSI_STATE_TERMINATE) {
		debug_scsi("failing host reset: session terminated "
			   "[CID %d age %d]", conn->id, session->age);
		spin_unlock_bh(&session->lock);
		return FAILED;
	}
	spin_unlock_bh(&session->lock);

	debug_scsi("failing connection CID %d due to SCSI host reset "
		   "[itt 0x%x age %d]", conn->id, ctask->itt,
		   session->age);
	iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	return SUCCESS;
}

static void
iscsi_tmabort_timedout(unsigned long data)
{
	struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)data;
	struct iscsi_conn *conn = ctask->conn;
	struct iscsi_session *session = conn->session;

	spin_lock(&session->lock);
	if (conn->tmabort_state == TMABORT_INITIAL) {
		__kfifo_put(session->mgmtpool.queue,
				(void*)&ctask->mtask, sizeof(void*));
		conn->tmabort_state = TMABORT_TIMEDOUT;
		debug_scsi("tmabort timedout [sc %lx itt 0x%x]\n",
			(long)ctask->sc, ctask->itt);
		/* unblock eh_abort() */
		wake_up(&conn->ehwait);
	}
	spin_unlock(&session->lock);
}

static int
iscsi_eh_abort(struct scsi_cmnd *sc)
{
	int rc;
	struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
	struct iscsi_conn *conn = ctask->conn;
	struct iscsi_session *session = conn->session;

	conn->eh_abort_cnt++;
	debug_scsi("aborting [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);

	/*
	 * two cases for ERL=0 here:
	 *
	 * 1) connection-level failure;
	 * 2) recovery due protocol error;
	 */
	down(&conn->xmitsema);
	spin_lock_bh(&session->lock);
	if (session->state != ISCSI_STATE_LOGGED_IN) {
		if (session->state == ISCSI_STATE_TERMINATE) {
			spin_unlock_bh(&session->lock);
			up(&conn->xmitsema);
			goto failed;
		}
		spin_unlock_bh(&session->lock);
	} else {
		struct iscsi_tm *hdr = &conn->tmhdr;

		/*
		 * Still LOGGED_IN...
		 */

		if (!ctask->sc || sc->SCp.phase != session->age) {
			/*
			 * 1) ctask completed before time out. But session
			 *    is still ok => Happy Retry.
			 * 2) session was re-open during time out of ctask.
			 */
			spin_unlock_bh(&session->lock);
			up(&conn->xmitsema);
			goto success;
		}
		conn->tmabort_state = TMABORT_INITIAL;
		spin_unlock_bh(&session->lock);

		/*
		 * ctask timed out but session is OK
		 * ERL=0 requires task mgmt abort to be issued on each
		 * failed command. requests must be serialized.
		 */
		memset(hdr, 0, sizeof(struct iscsi_tm));
		hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
		hdr->flags = ISCSI_TM_FUNC_ABORT_TASK;
		hdr->flags |= ISCSI_FLAG_CMD_FINAL;
		memcpy(hdr->lun, ctask->hdr.lun, sizeof(hdr->lun));
		hdr->rtt = ctask->hdr.itt;
		hdr->refcmdsn = ctask->hdr.cmdsn;

		rc = iscsi_conn_send_generic(conn, (struct iscsi_hdr *)hdr,
					     NULL, 0);
		if (rc) {
			iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
			debug_scsi("abort sent failure [itt 0x%x]", ctask->itt);
		} else {
			struct iscsi_r2t_info *r2t;

			/*
			 * TMF abort vs. TMF response race logic
			 */
			spin_lock_bh(&session->lock);
			ctask->mtask = (struct iscsi_mgmt_task *)
				session->mgmt_cmds[(hdr->itt & ITT_MASK) -
							ISCSI_MGMT_ITT_OFFSET];
			/*
			 * have to flush r2tqueue to avoid r2t leaks
			 */
			while (__kfifo_get(ctask->r2tqueue, (void*)&r2t,
				sizeof(void*))) {
				__kfifo_put(ctask->r2tpool.queue, (void*)&r2t,
					sizeof(void*));
			}
			if (conn->tmabort_state == TMABORT_INITIAL) {
				conn->tmfcmd_pdus_cnt++;
				conn->tmabort_timer.expires = 3*HZ + jiffies;
				conn->tmabort_timer.function =
						iscsi_tmabort_timedout;
				conn->tmabort_timer.data = (unsigned long)ctask;
				add_timer(&conn->tmabort_timer);
				debug_scsi("abort sent [itt 0x%x]", ctask->itt);
			} else {
				if (!ctask->sc ||
				    conn->tmabort_state == TMABORT_SUCCESS) {
					conn->tmabort_state = TMABORT_INITIAL;
					spin_unlock_bh(&session->lock);
					up(&conn->xmitsema);
					goto success;
				}
				conn->tmabort_state = TMABORT_INITIAL;
				iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
			}
			spin_unlock_bh(&session->lock);
		}
	}
	up(&conn->xmitsema);


	/*
	 * block eh thread until:
	 *
	 * 1) abort response;
	 * 2) abort timeout;
	 * 3) session re-opened;
	 * 4) session terminated;
	 */
	for (;;) {
		int p_state = session->state;

		rc = wait_event_interruptible(conn->ehwait,
			(p_state == ISCSI_STATE_LOGGED_IN ?
			 (session->state == ISCSI_STATE_TERMINATE ||
			  conn->tmabort_state != TMABORT_INITIAL) :
			 (session->state == ISCSI_STATE_TERMINATE ||
			  session->state == ISCSI_STATE_LOGGED_IN)));
		if (rc) {
			/* shutdown.. */
			session->state = ISCSI_STATE_TERMINATE;
			goto failed;
		}

		if (signal_pending(current))
			flush_signals(current);

		if (session->state == ISCSI_STATE_TERMINATE)
			goto failed;

		spin_lock_bh(&session->lock);
		if (sc->SCp.phase == session->age &&
		   (conn->tmabort_state == TMABORT_TIMEDOUT ||
		    conn->tmabort_state == TMABORT_FAILED)) {
			conn->tmabort_state = TMABORT_INITIAL;
			if (!ctask->sc) {
				/*
				 * ctask completed before tmf abort response or
				 * time out.
				 * But session is still ok => Happy Retry.
				 */
				spin_unlock_bh(&session->lock);
				break;
			}
			spin_unlock_bh(&session->lock);
			iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
			continue;
		}
		spin_unlock_bh(&session->lock);
		break;
	}

success:
	debug_scsi("abort success [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
	rc = SUCCESS;
	goto exit;

failed:
	debug_scsi("abort failed [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
	rc = FAILED;

exit:
	del_timer_sync(&conn->tmabort_timer);

	down(&conn->xmitsema);
	if (conn->sock) {
		struct sock *sk = conn->sock->sk;

		write_lock_bh(&sk->sk_callback_lock);
		iscsi_ctask_cleanup(conn, ctask);
		write_unlock_bh(&sk->sk_callback_lock);
	}
	up(&conn->xmitsema);
	return rc;
}

static int
iscsi_r2tpool_alloc(struct iscsi_session *session)
{
	int i;
	int cmd_i;

	/*
	 * initialize per-task: R2T pool and xmit queue
	 */
	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
	        struct iscsi_cmd_task *ctask = session->cmds[cmd_i];

		/*
		 * pre-allocated x4 as much r2ts to handle race when
		 * target acks DataOut faster than we data_xmit() queues
		 * could replenish r2tqueue.
		 */

		/* R2T pool */
		if (iscsi_pool_init(&ctask->r2tpool, session->max_r2t * 4,
			(void***)&ctask->r2ts, sizeof(struct iscsi_r2t_info))) {
			goto r2t_alloc_fail;
		}

		/* R2T xmit queue */
		ctask->r2tqueue = kfifo_alloc(
		      session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
		if (ctask->r2tqueue == ERR_PTR(-ENOMEM)) {
			iscsi_pool_free(&ctask->r2tpool, (void**)ctask->r2ts);
			goto r2t_alloc_fail;
		}

		/*
		 * number of
		 * Data-Out PDU's within R2T-sequence can be quite big;
		 * using mempool
		 */
		ctask->datapool = mempool_create(ISCSI_DTASK_DEFAULT_MAX,
			 mempool_alloc_slab, mempool_free_slab, taskcache);
		if (ctask->datapool == NULL) {
			kfifo_free(ctask->r2tqueue);
			iscsi_pool_free(&ctask->r2tpool, (void**)ctask->r2ts);
			goto r2t_alloc_fail;
		}
		INIT_LIST_HEAD(&ctask->dataqueue);
	}

	return 0;

r2t_alloc_fail:
	for (i = 0; i < cmd_i; i++) {
		mempool_destroy(session->cmds[i]->datapool);
		kfifo_free(session->cmds[i]->r2tqueue);
		iscsi_pool_free(&session->cmds[i]->r2tpool,
				(void**)session->cmds[i]->r2ts);
	}
	return -ENOMEM;
}

static void
iscsi_r2tpool_free(struct iscsi_session *session)
{
	int i;

	for (i = 0; i < session->cmds_max; i++) {
		mempool_destroy(session->cmds[i]->datapool);
		kfifo_free(session->cmds[i]->r2tqueue);
		iscsi_pool_free(&session->cmds[i]->r2tpool,
				(void**)session->cmds[i]->r2ts);
	}
}

static struct scsi_host_template iscsi_sht = {
	.name			= "iSCSI Initiator over TCP/IP, v."
				  ISCSI_VERSION_STR,
	.queuecommand           = iscsi_queuecommand,
	.change_queue_depth	= iscsi_change_queue_depth,
	.can_queue		= ISCSI_XMIT_CMDS_MAX - 1,
	.sg_tablesize		= ISCSI_SG_TABLESIZE,
	.cmd_per_lun		= ISCSI_DEF_CMD_PER_LUN,
	.eh_abort_handler       = iscsi_eh_abort,
	.eh_host_reset_handler	= iscsi_eh_host_reset,
	.use_clustering         = DISABLE_CLUSTERING,
	.proc_name		= "iscsi_tcp",
	.this_id		= -1,
};

static iscsi_sessionh_t
iscsi_session_create(uint32_t initial_cmdsn, struct Scsi_Host *host)
{
	int cmd_i;
	struct iscsi_session *session;

	session = iscsi_hostdata(host->hostdata);
	memset(session, 0, sizeof(struct iscsi_session));

	session->host = host;
	session->id = host->host_no;
	session->state = ISCSI_STATE_LOGGED_IN;
	session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;
	session->cmds_max = ISCSI_XMIT_CMDS_MAX;
	session->cmdsn = initial_cmdsn;
	session->exp_cmdsn = initial_cmdsn + 1;
	session->max_cmdsn = initial_cmdsn + 1;
	session->max_r2t = 1;

	/* initialize SCSI PDU commands pool */
	if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
		(void***)&session->cmds, sizeof(struct iscsi_cmd_task)))
		goto cmdpool_alloc_fail;

	/* pre-format cmds pool with ITT */
	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++)
		session->cmds[cmd_i]->itt = cmd_i;

	spin_lock_init(&session->lock);
	INIT_LIST_HEAD(&session->connections);

	/* initialize immediate command pool */
	if (iscsi_pool_init(&session->mgmtpool, session->mgmtpool_max,
		(void***)&session->mgmt_cmds, sizeof(struct iscsi_mgmt_task)))
		goto mgmtpool_alloc_fail;


	/* pre-format immediate cmds pool with ITT */
	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
		session->mgmt_cmds[cmd_i]->itt = ISCSI_MGMT_ITT_OFFSET + cmd_i;
		session->mgmt_cmds[cmd_i]->data = kmalloc(
			DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH, GFP_KERNEL);
		if (!session->mgmt_cmds[cmd_i]->data) {
			int j;

			for (j = 0; j < cmd_i; j++)
				kfree(session->mgmt_cmds[j]->data);
			goto immdata_alloc_fail;
		}
	}

	if (iscsi_r2tpool_alloc(session))
		goto r2tpool_alloc_fail;

	return iscsi_handle(session);

r2tpool_alloc_fail:
	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++)
		kfree(session->mgmt_cmds[cmd_i]->data);
	iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
immdata_alloc_fail:
mgmtpool_alloc_fail:
	iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
cmdpool_alloc_fail:
	return iscsi_handle(NULL);
}

static void
iscsi_session_destroy(iscsi_sessionh_t sessionh)
{
	int cmd_i;
	struct iscsi_data_task *dtask, *n;
	struct iscsi_session *session = iscsi_ptr(sessionh);

	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
		struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
		list_for_each_entry_safe(dtask, n, &ctask->dataqueue, item) {
			list_del(&dtask->item);
			mempool_free(dtask, ctask->datapool);
		}
	}

	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++)
		kfree(session->mgmt_cmds[cmd_i]->data);

	iscsi_r2tpool_free(session);
	iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
	iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
}

static int
iscsi_conn_set_param(iscsi_connh_t connh, enum iscsi_param param,
		     uint32_t value)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);
	struct iscsi_session *session = conn->session;

	spin_lock_bh(&session->lock);
	if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
	    conn->stop_stage != STOP_CONN_RECOVER) {
		printk(KERN_ERR "iscsi_tcp: can not change parameter [%d]\n",
		       param);
		spin_unlock_bh(&session->lock);
		return 0;
	}
	spin_unlock_bh(&session->lock);

	switch(param) {
	case ISCSI_PARAM_MAX_RECV_DLENGTH: {
		char *saveptr = conn->data;
		gfp_t flags = GFP_KERNEL;

		if (conn->data_size >= value) {
			conn->max_recv_dlength = value;
			break;
		}

		spin_lock_bh(&session->lock);
		if (conn->stop_stage == STOP_CONN_RECOVER)
			flags = GFP_ATOMIC;
		spin_unlock_bh(&session->lock);

		if (value <= PAGE_SIZE)
			conn->data = kmalloc(value, flags);
		else
			conn->data = (void*)__get_free_pages(flags,
							     get_order(value));
		if (conn->data == NULL) {
			conn->data = saveptr;
			return -ENOMEM;
		}
		if (conn->data_size <= PAGE_SIZE)
			kfree(saveptr);
		else
			free_pages((unsigned long)saveptr,
				   get_order(conn->data_size));
		conn->max_recv_dlength = value;
		conn->data_size = value;
		}
		break;
	case ISCSI_PARAM_MAX_XMIT_DLENGTH:
		conn->max_xmit_dlength =  value;
		break;
	case ISCSI_PARAM_HDRDGST_EN:
		conn->hdrdgst_en = value;
		conn->hdr_size = sizeof(struct iscsi_hdr);
		if (conn->hdrdgst_en) {
			conn->hdr_size += sizeof(__u32);
			if (!conn->tx_tfm)
				conn->tx_tfm = crypto_alloc_tfm("crc32c", 0);
			if (!conn->tx_tfm)
				return -ENOMEM;
			if (!conn->rx_tfm)
				conn->rx_tfm = crypto_alloc_tfm("crc32c", 0);
			if (!conn->rx_tfm) {
				crypto_free_tfm(conn->tx_tfm);
				return -ENOMEM;
			}
		} else {
			if (conn->tx_tfm)
				crypto_free_tfm(conn->tx_tfm);
			if (conn->rx_tfm)
				crypto_free_tfm(conn->rx_tfm);
		}
		break;
	case ISCSI_PARAM_DATADGST_EN:
		conn->datadgst_en = value;
		if (conn->datadgst_en) {
			if (!conn->data_tx_tfm)
				conn->data_tx_tfm =
				    crypto_alloc_tfm("crc32c", 0);
			if (!conn->data_tx_tfm)
				return -ENOMEM;
			if (!conn->data_rx_tfm)
				conn->data_rx_tfm =
				    crypto_alloc_tfm("crc32c", 0);
			if (!conn->data_rx_tfm) {
				crypto_free_tfm(conn->data_tx_tfm);
				return -ENOMEM;
			}
		} else {
			if (conn->data_tx_tfm)
				crypto_free_tfm(conn->data_tx_tfm);
			if (conn->data_rx_tfm)
				crypto_free_tfm(conn->data_rx_tfm);
		}
		break;
	case ISCSI_PARAM_INITIAL_R2T_EN:
		session->initial_r2t_en = value;
		break;
	case ISCSI_PARAM_MAX_R2T:
		if (session->max_r2t == roundup_pow_of_two(value))
			break;
		iscsi_r2tpool_free(session);
		session->max_r2t = value;
		if (session->max_r2t & (session->max_r2t - 1))
			session->max_r2t = roundup_pow_of_two(session->max_r2t);
		if (iscsi_r2tpool_alloc(session))
			return -ENOMEM;
		break;
	case ISCSI_PARAM_IMM_DATA_EN:
		session->imm_data_en = value;
		break;
	case ISCSI_PARAM_FIRST_BURST:
		session->first_burst = value;
		break;
	case ISCSI_PARAM_MAX_BURST:
		session->max_burst = value;
		break;
	case ISCSI_PARAM_PDU_INORDER_EN:
		session->pdu_inorder_en = value;
		break;
	case ISCSI_PARAM_DATASEQ_INORDER_EN:
		session->dataseq_inorder_en = value;
		break;
	case ISCSI_PARAM_ERL:
		session->erl = value;
		break;
	case ISCSI_PARAM_IFMARKER_EN:
		BUG_ON(value);
		session->ifmarker_en = value;
		break;
	case ISCSI_PARAM_OFMARKER_EN:
		BUG_ON(value);
		session->ofmarker_en = value;
		break;
	default:
		break;
	}

	return 0;
}

static int
iscsi_conn_get_param(iscsi_connh_t connh, enum iscsi_param param,
		     uint32_t *value)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);
	struct iscsi_session *session = conn->session;

	switch(param) {
	case ISCSI_PARAM_MAX_RECV_DLENGTH:
		*value = conn->max_recv_dlength;
		break;
	case ISCSI_PARAM_MAX_XMIT_DLENGTH:
		*value = conn->max_xmit_dlength;
		break;
	case ISCSI_PARAM_HDRDGST_EN:
		*value = conn->hdrdgst_en;
		break;
	case ISCSI_PARAM_DATADGST_EN:
		*value = conn->datadgst_en;
		break;
	case ISCSI_PARAM_INITIAL_R2T_EN:
		*value = session->initial_r2t_en;
		break;
	case ISCSI_PARAM_MAX_R2T:
		*value = session->max_r2t;
		break;
	case ISCSI_PARAM_IMM_DATA_EN:
		*value = session->imm_data_en;
		break;
	case ISCSI_PARAM_FIRST_BURST:
		*value = session->first_burst;
		break;
	case ISCSI_PARAM_MAX_BURST:
		*value = session->max_burst;
		break;
	case ISCSI_PARAM_PDU_INORDER_EN:
		*value = session->pdu_inorder_en;
		break;
	case ISCSI_PARAM_DATASEQ_INORDER_EN:
		*value = session->dataseq_inorder_en;
		break;
	case ISCSI_PARAM_ERL:
		*value = session->erl;
		break;
	case ISCSI_PARAM_IFMARKER_EN:
		*value = session->ifmarker_en;
		break;
	case ISCSI_PARAM_OFMARKER_EN:
		*value = session->ofmarker_en;
		break;
	default:
		return ISCSI_ERR_PARAM_NOT_FOUND;
	}

	return 0;
}

static void
iscsi_conn_get_stats(iscsi_connh_t connh, struct iscsi_stats *stats)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);

	stats->txdata_octets = conn->txdata_octets;
	stats->rxdata_octets = conn->rxdata_octets;
	stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
	stats->dataout_pdus = conn->dataout_pdus_cnt;
	stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
	stats->datain_pdus = conn->datain_pdus_cnt;
	stats->r2t_pdus = conn->r2t_pdus_cnt;
	stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
	stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
	stats->custom_length = 3;
	strcpy(stats->custom[0].desc, "tx_sendpage_failures");
	stats->custom[0].value = conn->sendpage_failures_cnt;
	strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
	stats->custom[1].value = conn->discontiguous_hdr_cnt;
	strcpy(stats->custom[2].desc, "eh_abort_cnt");
	stats->custom[2].value = conn->eh_abort_cnt;
}

static int
iscsi_conn_send_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr, char *data,
		    uint32_t data_size)
{
	struct iscsi_conn *conn = iscsi_ptr(connh);
	int rc;

	down(&conn->xmitsema);
	rc = iscsi_conn_send_generic(conn, hdr, data, data_size);
	up(&conn->xmitsema);

	return rc;
}

static struct iscsi_transport iscsi_tcp_transport = {
	.owner			= THIS_MODULE,
	.name			= "tcp",
	.caps			= CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
				  | CAP_DATADGST,
	.host_template		= &iscsi_sht,
	.hostdata_size		= sizeof(struct iscsi_session),
	.max_conn		= 1,
	.max_cmd_len		= ISCSI_TCP_MAX_CMD_LEN,
	.create_session		= iscsi_session_create,
	.destroy_session	= iscsi_session_destroy,
	.create_conn		= iscsi_conn_create,
	.bind_conn		= iscsi_conn_bind,
	.destroy_conn		= iscsi_conn_destroy,
	.set_param		= iscsi_conn_set_param,
	.get_param		= iscsi_conn_get_param,
	.start_conn		= iscsi_conn_start,
	.stop_conn		= iscsi_conn_stop,
	.send_pdu		= iscsi_conn_send_pdu,
	.get_stats		= iscsi_conn_get_stats,
};

static int __init
iscsi_tcp_init(void)
{
	int error;

	if (iscsi_max_lun < 1) {
		printk(KERN_ERR "Invalid max_lun value of %u\n", iscsi_max_lun);
		return -EINVAL;
	}
	iscsi_tcp_transport.max_lun = iscsi_max_lun;

	taskcache = kmem_cache_create("iscsi_taskcache",
			sizeof(struct iscsi_data_task), 0,
			SLAB_HWCACHE_ALIGN | SLAB_NO_REAP, NULL, NULL);
	if (!taskcache)
		return -ENOMEM;

	error = iscsi_register_transport(&iscsi_tcp_transport);
	if (error)
		kmem_cache_destroy(taskcache);

	return error;
}

static void __exit
iscsi_tcp_exit(void)
{
	iscsi_unregister_transport(&iscsi_tcp_transport);
	kmem_cache_destroy(taskcache);
}

module_init(iscsi_tcp_init);
module_exit(iscsi_tcp_exit);