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-rw-r--r--block/Makefile3
-rw-r--r--block/blk-core.c719
-rw-r--r--block/blk-sysfs.c298
-rw-r--r--block/blk-tag.c396
-rw-r--r--block/blk.h29
5 files changed, 735 insertions, 710 deletions
diff --git a/block/Makefile b/block/Makefile
index 75597c1263e0..fcaae4ae6704 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -2,7 +2,8 @@
2# Makefile for the kernel block layer 2# Makefile for the kernel block layer
3# 3#
4 4
5obj-$(CONFIG_BLOCK) := elevator.o blk-core.o ioctl.o genhd.o scsi_ioctl.o 5obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o ioctl.o \
6 genhd.o scsi_ioctl.o
6 7
7obj-$(CONFIG_BLK_DEV_BSG) += bsg.o 8obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
8obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o 9obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
diff --git a/block/blk-core.c b/block/blk-core.c
index 1932a56f5e4b..937f9d0b9bd5 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -32,6 +32,8 @@
32#include <linux/fault-inject.h> 32#include <linux/fault-inject.h>
33#include <linux/scatterlist.h> 33#include <linux/scatterlist.h>
34 34
35#include "blk.h"
36
35/* 37/*
36 * for max sense size 38 * for max sense size
37 */ 39 */
@@ -50,12 +52,12 @@ static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
50/* 52/*
51 * For the allocated request tables 53 * For the allocated request tables
52 */ 54 */
53static struct kmem_cache *request_cachep; 55struct kmem_cache *request_cachep;
54 56
55/* 57/*
56 * For queue allocation 58 * For queue allocation
57 */ 59 */
58static struct kmem_cache *requestq_cachep; 60struct kmem_cache *blk_requestq_cachep = NULL;
59 61
60/* 62/*
61 * For io context allocations 63 * For io context allocations
@@ -80,25 +82,7 @@ static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
80/* Number of requests a "batching" process may submit */ 82/* Number of requests a "batching" process may submit */
81#define BLK_BATCH_REQ 32 83#define BLK_BATCH_REQ 32
82 84
83/* 85void blk_queue_congestion_threshold(struct request_queue *q)
84 * Return the threshold (number of used requests) at which the queue is
85 * considered to be congested. It include a little hysteresis to keep the
86 * context switch rate down.
87 */
88static inline int queue_congestion_on_threshold(struct request_queue *q)
89{
90 return q->nr_congestion_on;
91}
92
93/*
94 * The threshold at which a queue is considered to be uncongested
95 */
96static inline int queue_congestion_off_threshold(struct request_queue *q)
97{
98 return q->nr_congestion_off;
99}
100
101static void blk_queue_congestion_threshold(struct request_queue *q)
102{ 86{
103 int nr; 87 int nr;
104 88
@@ -817,397 +801,6 @@ void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
817 801
818EXPORT_SYMBOL(blk_queue_update_dma_alignment); 802EXPORT_SYMBOL(blk_queue_update_dma_alignment);
819 803
820/**
821 * blk_queue_find_tag - find a request by its tag and queue
822 * @q: The request queue for the device
823 * @tag: The tag of the request
824 *
825 * Notes:
826 * Should be used when a device returns a tag and you want to match
827 * it with a request.
828 *
829 * no locks need be held.
830 **/
831struct request *blk_queue_find_tag(struct request_queue *q, int tag)
832{
833 return blk_map_queue_find_tag(q->queue_tags, tag);
834}
835
836EXPORT_SYMBOL(blk_queue_find_tag);
837
838/**
839 * __blk_free_tags - release a given set of tag maintenance info
840 * @bqt: the tag map to free
841 *
842 * Tries to free the specified @bqt@. Returns true if it was
843 * actually freed and false if there are still references using it
844 */
845static int __blk_free_tags(struct blk_queue_tag *bqt)
846{
847 int retval;
848
849 retval = atomic_dec_and_test(&bqt->refcnt);
850 if (retval) {
851 BUG_ON(bqt->busy);
852
853 kfree(bqt->tag_index);
854 bqt->tag_index = NULL;
855
856 kfree(bqt->tag_map);
857 bqt->tag_map = NULL;
858
859 kfree(bqt);
860
861 }
862
863 return retval;
864}
865
866/**
867 * __blk_queue_free_tags - release tag maintenance info
868 * @q: the request queue for the device
869 *
870 * Notes:
871 * blk_cleanup_queue() will take care of calling this function, if tagging
872 * has been used. So there's no need to call this directly.
873 **/
874static void __blk_queue_free_tags(struct request_queue *q)
875{
876 struct blk_queue_tag *bqt = q->queue_tags;
877
878 if (!bqt)
879 return;
880
881 __blk_free_tags(bqt);
882
883 q->queue_tags = NULL;
884 q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED);
885}
886
887
888/**
889 * blk_free_tags - release a given set of tag maintenance info
890 * @bqt: the tag map to free
891 *
892 * For externally managed @bqt@ frees the map. Callers of this
893 * function must guarantee to have released all the queues that
894 * might have been using this tag map.
895 */
896void blk_free_tags(struct blk_queue_tag *bqt)
897{
898 if (unlikely(!__blk_free_tags(bqt)))
899 BUG();
900}
901EXPORT_SYMBOL(blk_free_tags);
902
903/**
904 * blk_queue_free_tags - release tag maintenance info
905 * @q: the request queue for the device
906 *
907 * Notes:
908 * This is used to disabled tagged queuing to a device, yet leave
909 * queue in function.
910 **/
911void blk_queue_free_tags(struct request_queue *q)
912{
913 clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
914}
915
916EXPORT_SYMBOL(blk_queue_free_tags);
917
918static int
919init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth)
920{
921 struct request **tag_index;
922 unsigned long *tag_map;
923 int nr_ulongs;
924
925 if (q && depth > q->nr_requests * 2) {
926 depth = q->nr_requests * 2;
927 printk(KERN_ERR "%s: adjusted depth to %d\n",
928 __FUNCTION__, depth);
929 }
930
931 tag_index = kzalloc(depth * sizeof(struct request *), GFP_ATOMIC);
932 if (!tag_index)
933 goto fail;
934
935 nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
936 tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
937 if (!tag_map)
938 goto fail;
939
940 tags->real_max_depth = depth;
941 tags->max_depth = depth;
942 tags->tag_index = tag_index;
943 tags->tag_map = tag_map;
944
945 return 0;
946fail:
947 kfree(tag_index);
948 return -ENOMEM;
949}
950
951static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
952 int depth)
953{
954 struct blk_queue_tag *tags;
955
956 tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
957 if (!tags)
958 goto fail;
959
960 if (init_tag_map(q, tags, depth))
961 goto fail;
962
963 tags->busy = 0;
964 atomic_set(&tags->refcnt, 1);
965 return tags;
966fail:
967 kfree(tags);
968 return NULL;
969}
970
971/**
972 * blk_init_tags - initialize the tag info for an external tag map
973 * @depth: the maximum queue depth supported
974 * @tags: the tag to use
975 **/
976struct blk_queue_tag *blk_init_tags(int depth)
977{
978 return __blk_queue_init_tags(NULL, depth);
979}
980EXPORT_SYMBOL(blk_init_tags);
981
982/**
983 * blk_queue_init_tags - initialize the queue tag info
984 * @q: the request queue for the device
985 * @depth: the maximum queue depth supported
986 * @tags: the tag to use
987 **/
988int blk_queue_init_tags(struct request_queue *q, int depth,
989 struct blk_queue_tag *tags)
990{
991 int rc;
992
993 BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
994
995 if (!tags && !q->queue_tags) {
996 tags = __blk_queue_init_tags(q, depth);
997
998 if (!tags)
999 goto fail;
1000 } else if (q->queue_tags) {
1001 if ((rc = blk_queue_resize_tags(q, depth)))
1002 return rc;
1003 set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
1004 return 0;
1005 } else
1006 atomic_inc(&tags->refcnt);
1007
1008 /*
1009 * assign it, all done
1010 */
1011 q->queue_tags = tags;
1012 q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
1013 INIT_LIST_HEAD(&q->tag_busy_list);
1014 return 0;
1015fail:
1016 kfree(tags);
1017 return -ENOMEM;
1018}
1019
1020EXPORT_SYMBOL(blk_queue_init_tags);
1021
1022/**
1023 * blk_queue_resize_tags - change the queueing depth
1024 * @q: the request queue for the device
1025 * @new_depth: the new max command queueing depth
1026 *
1027 * Notes:
1028 * Must be called with the queue lock held.
1029 **/
1030int blk_queue_resize_tags(struct request_queue *q, int new_depth)
1031{
1032 struct blk_queue_tag *bqt = q->queue_tags;
1033 struct request **tag_index;
1034 unsigned long *tag_map;
1035 int max_depth, nr_ulongs;
1036
1037 if (!bqt)
1038 return -ENXIO;
1039
1040 /*
1041 * if we already have large enough real_max_depth. just
1042 * adjust max_depth. *NOTE* as requests with tag value
1043 * between new_depth and real_max_depth can be in-flight, tag
1044 * map can not be shrunk blindly here.
1045 */
1046 if (new_depth <= bqt->real_max_depth) {
1047 bqt->max_depth = new_depth;
1048 return 0;
1049 }
1050
1051 /*
1052 * Currently cannot replace a shared tag map with a new
1053 * one, so error out if this is the case
1054 */
1055 if (atomic_read(&bqt->refcnt) != 1)
1056 return -EBUSY;
1057
1058 /*
1059 * save the old state info, so we can copy it back
1060 */
1061 tag_index = bqt->tag_index;
1062 tag_map = bqt->tag_map;
1063 max_depth = bqt->real_max_depth;
1064
1065 if (init_tag_map(q, bqt, new_depth))
1066 return -ENOMEM;
1067
1068 memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
1069 nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
1070 memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
1071
1072 kfree(tag_index);
1073 kfree(tag_map);
1074 return 0;
1075}
1076
1077EXPORT_SYMBOL(blk_queue_resize_tags);
1078
1079/**
1080 * blk_queue_end_tag - end tag operations for a request
1081 * @q: the request queue for the device
1082 * @rq: the request that has completed
1083 *
1084 * Description:
1085 * Typically called when end_that_request_first() returns 0, meaning
1086 * all transfers have been done for a request. It's important to call
1087 * this function before end_that_request_last(), as that will put the
1088 * request back on the free list thus corrupting the internal tag list.
1089 *
1090 * Notes:
1091 * queue lock must be held.
1092 **/
1093void blk_queue_end_tag(struct request_queue *q, struct request *rq)
1094{
1095 struct blk_queue_tag *bqt = q->queue_tags;
1096 int tag = rq->tag;
1097
1098 BUG_ON(tag == -1);
1099
1100 if (unlikely(tag >= bqt->real_max_depth))
1101 /*
1102 * This can happen after tag depth has been reduced.
1103 * FIXME: how about a warning or info message here?
1104 */
1105 return;
1106
1107 list_del_init(&rq->queuelist);
1108 rq->cmd_flags &= ~REQ_QUEUED;
1109 rq->tag = -1;
1110
1111 if (unlikely(bqt->tag_index[tag] == NULL))
1112 printk(KERN_ERR "%s: tag %d is missing\n",
1113 __FUNCTION__, tag);
1114
1115 bqt->tag_index[tag] = NULL;
1116
1117 if (unlikely(!test_bit(tag, bqt->tag_map))) {
1118 printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
1119 __FUNCTION__, tag);
1120 return;
1121 }
1122 /*
1123 * The tag_map bit acts as a lock for tag_index[bit], so we need
1124 * unlock memory barrier semantics.
1125 */
1126 clear_bit_unlock(tag, bqt->tag_map);
1127 bqt->busy--;
1128}
1129
1130EXPORT_SYMBOL(blk_queue_end_tag);
1131
1132/**
1133 * blk_queue_start_tag - find a free tag and assign it
1134 * @q: the request queue for the device
1135 * @rq: the block request that needs tagging
1136 *
1137 * Description:
1138 * This can either be used as a stand-alone helper, or possibly be
1139 * assigned as the queue &prep_rq_fn (in which case &struct request
1140 * automagically gets a tag assigned). Note that this function
1141 * assumes that any type of request can be queued! if this is not
1142 * true for your device, you must check the request type before
1143 * calling this function. The request will also be removed from
1144 * the request queue, so it's the drivers responsibility to readd
1145 * it if it should need to be restarted for some reason.
1146 *
1147 * Notes:
1148 * queue lock must be held.
1149 **/
1150int blk_queue_start_tag(struct request_queue *q, struct request *rq)
1151{
1152 struct blk_queue_tag *bqt = q->queue_tags;
1153 int tag;
1154
1155 if (unlikely((rq->cmd_flags & REQ_QUEUED))) {
1156 printk(KERN_ERR
1157 "%s: request %p for device [%s] already tagged %d",
1158 __FUNCTION__, rq,
1159 rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
1160 BUG();
1161 }
1162
1163 /*
1164 * Protect against shared tag maps, as we may not have exclusive
1165 * access to the tag map.
1166 */
1167 do {
1168 tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
1169 if (tag >= bqt->max_depth)
1170 return 1;
1171
1172 } while (test_and_set_bit_lock(tag, bqt->tag_map));
1173 /*
1174 * We need lock ordering semantics given by test_and_set_bit_lock.
1175 * See blk_queue_end_tag for details.
1176 */
1177
1178 rq->cmd_flags |= REQ_QUEUED;
1179 rq->tag = tag;
1180 bqt->tag_index[tag] = rq;
1181 blkdev_dequeue_request(rq);
1182 list_add(&rq->queuelist, &q->tag_busy_list);
1183 bqt->busy++;
1184 return 0;
1185}
1186
1187EXPORT_SYMBOL(blk_queue_start_tag);
1188
1189/**
1190 * blk_queue_invalidate_tags - invalidate all pending tags
1191 * @q: the request queue for the device
1192 *
1193 * Description:
1194 * Hardware conditions may dictate a need to stop all pending requests.
1195 * In this case, we will safely clear the block side of the tag queue and
1196 * readd all requests to the request queue in the right order.
1197 *
1198 * Notes:
1199 * queue lock must be held.
1200 **/
1201void blk_queue_invalidate_tags(struct request_queue *q)
1202{
1203 struct list_head *tmp, *n;
1204
1205 list_for_each_safe(tmp, n, &q->tag_busy_list)
1206 blk_requeue_request(q, list_entry_rq(tmp));
1207}
1208
1209EXPORT_SYMBOL(blk_queue_invalidate_tags);
1210
1211void blk_dump_rq_flags(struct request *rq, char *msg) 804void blk_dump_rq_flags(struct request *rq, char *msg)
1212{ 805{
1213 int bit; 806 int bit;
@@ -1828,41 +1421,6 @@ void blk_run_queue(struct request_queue *q)
1828} 1421}
1829EXPORT_SYMBOL(blk_run_queue); 1422EXPORT_SYMBOL(blk_run_queue);
1830 1423
1831/**
1832 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
1833 * @kobj: the kobj belonging of the request queue to be released
1834 *
1835 * Description:
1836 * blk_cleanup_queue is the pair to blk_init_queue() or
1837 * blk_queue_make_request(). It should be called when a request queue is
1838 * being released; typically when a block device is being de-registered.
1839 * Currently, its primary task it to free all the &struct request
1840 * structures that were allocated to the queue and the queue itself.
1841 *
1842 * Caveat:
1843 * Hopefully the low level driver will have finished any
1844 * outstanding requests first...
1845 **/
1846static void blk_release_queue(struct kobject *kobj)
1847{
1848 struct request_queue *q =
1849 container_of(kobj, struct request_queue, kobj);
1850 struct request_list *rl = &q->rq;
1851
1852 blk_sync_queue(q);
1853
1854 if (rl->rq_pool)
1855 mempool_destroy(rl->rq_pool);
1856
1857 if (q->queue_tags)
1858 __blk_queue_free_tags(q);
1859
1860 blk_trace_shutdown(q);
1861
1862 bdi_destroy(&q->backing_dev_info);
1863 kmem_cache_free(requestq_cachep, q);
1864}
1865
1866void blk_put_queue(struct request_queue *q) 1424void blk_put_queue(struct request_queue *q)
1867{ 1425{
1868 kobject_put(&q->kobj); 1426 kobject_put(&q->kobj);
@@ -1908,14 +1466,12 @@ struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
1908} 1466}
1909EXPORT_SYMBOL(blk_alloc_queue); 1467EXPORT_SYMBOL(blk_alloc_queue);
1910 1468
1911static struct kobj_type queue_ktype;
1912
1913struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) 1469struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
1914{ 1470{
1915 struct request_queue *q; 1471 struct request_queue *q;
1916 int err; 1472 int err;
1917 1473
1918 q = kmem_cache_alloc_node(requestq_cachep, 1474 q = kmem_cache_alloc_node(blk_requestq_cachep,
1919 gfp_mask | __GFP_ZERO, node_id); 1475 gfp_mask | __GFP_ZERO, node_id);
1920 if (!q) 1476 if (!q)
1921 return NULL; 1477 return NULL;
@@ -1924,13 +1480,13 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
1924 q->backing_dev_info.unplug_io_data = q; 1480 q->backing_dev_info.unplug_io_data = q;
1925 err = bdi_init(&q->backing_dev_info); 1481 err = bdi_init(&q->backing_dev_info);
1926 if (err) { 1482 if (err) {
1927 kmem_cache_free(requestq_cachep, q); 1483 kmem_cache_free(blk_requestq_cachep, q);
1928 return NULL; 1484 return NULL;
1929 } 1485 }
1930 1486
1931 init_timer(&q->unplug_timer); 1487 init_timer(&q->unplug_timer);
1932 1488
1933 kobject_init(&q->kobj, &queue_ktype); 1489 kobject_init(&q->kobj, &blk_queue_ktype);
1934 1490
1935 mutex_init(&q->sysfs_lock); 1491 mutex_init(&q->sysfs_lock);
1936 1492
@@ -1987,7 +1543,7 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
1987 1543
1988 q->node = node_id; 1544 q->node = node_id;
1989 if (blk_init_free_list(q)) { 1545 if (blk_init_free_list(q)) {
1990 kmem_cache_free(requestq_cachep, q); 1546 kmem_cache_free(blk_requestq_cachep, q);
1991 return NULL; 1547 return NULL;
1992 } 1548 }
1993 1549
@@ -4012,7 +3568,7 @@ int __init blk_dev_init(void)
4012 request_cachep = kmem_cache_create("blkdev_requests", 3568 request_cachep = kmem_cache_create("blkdev_requests",
4013 sizeof(struct request), 0, SLAB_PANIC, NULL); 3569 sizeof(struct request), 0, SLAB_PANIC, NULL);
4014 3570
4015 requestq_cachep = kmem_cache_create("blkdev_queue", 3571 blk_requestq_cachep = kmem_cache_create("blkdev_queue",
4016 sizeof(struct request_queue), 0, SLAB_PANIC, NULL); 3572 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
4017 3573
4018 iocontext_cachep = kmem_cache_create("blkdev_ioc", 3574 iocontext_cachep = kmem_cache_create("blkdev_ioc",
@@ -4200,258 +3756,3 @@ void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
4200} 3756}
4201EXPORT_SYMBOL(swap_io_context); 3757EXPORT_SYMBOL(swap_io_context);
4202 3758
4203/*
4204 * sysfs parts below
4205 */
4206struct queue_sysfs_entry {
4207 struct attribute attr;
4208 ssize_t (*show)(struct request_queue *, char *);
4209 ssize_t (*store)(struct request_queue *, const char *, size_t);
4210};
4211
4212static ssize_t
4213queue_var_show(unsigned int var, char *page)
4214{
4215 return sprintf(page, "%d\n", var);
4216}
4217
4218static ssize_t
4219queue_var_store(unsigned long *var, const char *page, size_t count)
4220{
4221 char *p = (char *) page;
4222
4223 *var = simple_strtoul(p, &p, 10);
4224 return count;
4225}
4226
4227static ssize_t queue_requests_show(struct request_queue *q, char *page)
4228{
4229 return queue_var_show(q->nr_requests, (page));
4230}
4231
4232static ssize_t
4233queue_requests_store(struct request_queue *q, const char *page, size_t count)
4234{
4235 struct request_list *rl = &q->rq;
4236 unsigned long nr;
4237 int ret = queue_var_store(&nr, page, count);
4238 if (nr < BLKDEV_MIN_RQ)
4239 nr = BLKDEV_MIN_RQ;
4240
4241 spin_lock_irq(q->queue_lock);
4242 q->nr_requests = nr;
4243 blk_queue_congestion_threshold(q);
4244
4245 if (rl->count[READ] >= queue_congestion_on_threshold(q))
4246 blk_set_queue_congested(q, READ);
4247 else if (rl->count[READ] < queue_congestion_off_threshold(q))
4248 blk_clear_queue_congested(q, READ);
4249
4250 if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
4251 blk_set_queue_congested(q, WRITE);
4252 else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
4253 blk_clear_queue_congested(q, WRITE);
4254
4255 if (rl->count[READ] >= q->nr_requests) {
4256 blk_set_queue_full(q, READ);
4257 } else if (rl->count[READ]+1 <= q->nr_requests) {
4258 blk_clear_queue_full(q, READ);
4259 wake_up(&rl->wait[READ]);
4260 }
4261
4262 if (rl->count[WRITE] >= q->nr_requests) {
4263 blk_set_queue_full(q, WRITE);
4264 } else if (rl->count[WRITE]+1 <= q->nr_requests) {
4265 blk_clear_queue_full(q, WRITE);
4266 wake_up(&rl->wait[WRITE]);
4267 }
4268 spin_unlock_irq(q->queue_lock);
4269 return ret;
4270}
4271
4272static ssize_t queue_ra_show(struct request_queue *q, char *page)
4273{
4274 int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
4275
4276 return queue_var_show(ra_kb, (page));
4277}
4278
4279static ssize_t
4280queue_ra_store(struct request_queue *q, const char *page, size_t count)
4281{
4282 unsigned long ra_kb;
4283 ssize_t ret = queue_var_store(&ra_kb, page, count);
4284
4285 spin_lock_irq(q->queue_lock);
4286 q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
4287 spin_unlock_irq(q->queue_lock);
4288
4289 return ret;
4290}
4291
4292static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
4293{
4294 int max_sectors_kb = q->max_sectors >> 1;
4295
4296 return queue_var_show(max_sectors_kb, (page));
4297}
4298
4299static ssize_t
4300queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
4301{
4302 unsigned long max_sectors_kb,
4303 max_hw_sectors_kb = q->max_hw_sectors >> 1,
4304 page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
4305 ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
4306
4307 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
4308 return -EINVAL;
4309 /*
4310 * Take the queue lock to update the readahead and max_sectors
4311 * values synchronously:
4312 */
4313 spin_lock_irq(q->queue_lock);
4314 q->max_sectors = max_sectors_kb << 1;
4315 spin_unlock_irq(q->queue_lock);
4316
4317 return ret;
4318}
4319
4320static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
4321{
4322 int max_hw_sectors_kb = q->max_hw_sectors >> 1;
4323
4324 return queue_var_show(max_hw_sectors_kb, (page));
4325}
4326
4327
4328static struct queue_sysfs_entry queue_requests_entry = {
4329 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
4330 .show = queue_requests_show,
4331 .store = queue_requests_store,
4332};
4333
4334static struct queue_sysfs_entry queue_ra_entry = {
4335 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
4336 .show = queue_ra_show,
4337 .store = queue_ra_store,
4338};
4339
4340static struct queue_sysfs_entry queue_max_sectors_entry = {
4341 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
4342 .show = queue_max_sectors_show,
4343 .store = queue_max_sectors_store,
4344};
4345
4346static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
4347 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
4348 .show = queue_max_hw_sectors_show,
4349};
4350
4351static struct queue_sysfs_entry queue_iosched_entry = {
4352 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
4353 .show = elv_iosched_show,
4354 .store = elv_iosched_store,
4355};
4356
4357static struct attribute *default_attrs[] = {
4358 &queue_requests_entry.attr,
4359 &queue_ra_entry.attr,
4360 &queue_max_hw_sectors_entry.attr,
4361 &queue_max_sectors_entry.attr,
4362 &queue_iosched_entry.attr,
4363 NULL,
4364};
4365
4366#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
4367
4368static ssize_t
4369queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
4370{
4371 struct queue_sysfs_entry *entry = to_queue(attr);
4372 struct request_queue *q =
4373 container_of(kobj, struct request_queue, kobj);
4374 ssize_t res;
4375
4376 if (!entry->show)
4377 return -EIO;
4378 mutex_lock(&q->sysfs_lock);
4379 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
4380 mutex_unlock(&q->sysfs_lock);
4381 return -ENOENT;
4382 }
4383 res = entry->show(q, page);
4384 mutex_unlock(&q->sysfs_lock);
4385 return res;
4386}
4387
4388static ssize_t
4389queue_attr_store(struct kobject *kobj, struct attribute *attr,
4390 const char *page, size_t length)
4391{
4392 struct queue_sysfs_entry *entry = to_queue(attr);
4393 struct request_queue *q = container_of(kobj, struct request_queue, kobj);
4394
4395 ssize_t res;
4396
4397 if (!entry->store)
4398 return -EIO;
4399 mutex_lock(&q->sysfs_lock);
4400 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
4401 mutex_unlock(&q->sysfs_lock);
4402 return -ENOENT;
4403 }
4404 res = entry->store(q, page, length);
4405 mutex_unlock(&q->sysfs_lock);
4406 return res;
4407}
4408
4409static struct sysfs_ops queue_sysfs_ops = {
4410 .show = queue_attr_show,
4411 .store = queue_attr_store,
4412};
4413
4414static struct kobj_type queue_ktype = {
4415 .sysfs_ops = &queue_sysfs_ops,
4416 .default_attrs = default_attrs,
4417 .release = blk_release_queue,
4418};
4419
4420int blk_register_queue(struct gendisk *disk)
4421{
4422 int ret;
4423
4424 struct request_queue *q = disk->queue;
4425
4426 if (!q || !q->request_fn)
4427 return -ENXIO;
4428
4429 ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
4430 "%s", "queue");
4431 if (ret < 0)
4432 return ret;
4433
4434 kobject_uevent(&q->kobj, KOBJ_ADD);
4435
4436 ret = elv_register_queue(q);
4437 if (ret) {
4438 kobject_uevent(&q->kobj, KOBJ_REMOVE);
4439 kobject_del(&q->kobj);
4440 return ret;
4441 }
4442
4443 return 0;
4444}
4445
4446void blk_unregister_queue(struct gendisk *disk)
4447{
4448 struct request_queue *q = disk->queue;
4449
4450 if (q && q->request_fn) {
4451 elv_unregister_queue(q);
4452
4453 kobject_uevent(&q->kobj, KOBJ_REMOVE);
4454 kobject_del(&q->kobj);
4455 kobject_put(&disk->dev.kobj);
4456 }
4457}
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
new file mode 100644
index 000000000000..d9b9afab3456
--- /dev/null
+++ b/block/blk-sysfs.c
@@ -0,0 +1,298 @@
1/*
2 * Functions related to sysfs handling
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8#include <linux/blktrace_api.h>
9
10#include "blk.h"
11
12struct queue_sysfs_entry {
13 struct attribute attr;
14 ssize_t (*show)(struct request_queue *, char *);
15 ssize_t (*store)(struct request_queue *, const char *, size_t);
16};
17
18static ssize_t
19queue_var_show(unsigned int var, char *page)
20{
21 return sprintf(page, "%d\n", var);
22}
23
24static ssize_t
25queue_var_store(unsigned long *var, const char *page, size_t count)
26{
27 char *p = (char *) page;
28
29 *var = simple_strtoul(p, &p, 10);
30 return count;
31}
32
33static ssize_t queue_requests_show(struct request_queue *q, char *page)
34{
35 return queue_var_show(q->nr_requests, (page));
36}
37
38static ssize_t
39queue_requests_store(struct request_queue *q, const char *page, size_t count)
40{
41 struct request_list *rl = &q->rq;
42 unsigned long nr;
43 int ret = queue_var_store(&nr, page, count);
44 if (nr < BLKDEV_MIN_RQ)
45 nr = BLKDEV_MIN_RQ;
46
47 spin_lock_irq(q->queue_lock);
48 q->nr_requests = nr;
49 blk_queue_congestion_threshold(q);
50
51 if (rl->count[READ] >= queue_congestion_on_threshold(q))
52 blk_set_queue_congested(q, READ);
53 else if (rl->count[READ] < queue_congestion_off_threshold(q))
54 blk_clear_queue_congested(q, READ);
55
56 if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
57 blk_set_queue_congested(q, WRITE);
58 else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
59 blk_clear_queue_congested(q, WRITE);
60
61 if (rl->count[READ] >= q->nr_requests) {
62 blk_set_queue_full(q, READ);
63 } else if (rl->count[READ]+1 <= q->nr_requests) {
64 blk_clear_queue_full(q, READ);
65 wake_up(&rl->wait[READ]);
66 }
67
68 if (rl->count[WRITE] >= q->nr_requests) {
69 blk_set_queue_full(q, WRITE);
70 } else if (rl->count[WRITE]+1 <= q->nr_requests) {
71 blk_clear_queue_full(q, WRITE);
72 wake_up(&rl->wait[WRITE]);
73 }
74 spin_unlock_irq(q->queue_lock);
75 return ret;
76}
77
78static ssize_t queue_ra_show(struct request_queue *q, char *page)
79{
80 int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
81
82 return queue_var_show(ra_kb, (page));
83}
84
85static ssize_t
86queue_ra_store(struct request_queue *q, const char *page, size_t count)
87{
88 unsigned long ra_kb;
89 ssize_t ret = queue_var_store(&ra_kb, page, count);
90
91 spin_lock_irq(q->queue_lock);
92 q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
93 spin_unlock_irq(q->queue_lock);
94
95 return ret;
96}
97
98static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
99{
100 int max_sectors_kb = q->max_sectors >> 1;
101
102 return queue_var_show(max_sectors_kb, (page));
103}
104
105static ssize_t
106queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
107{
108 unsigned long max_sectors_kb,
109 max_hw_sectors_kb = q->max_hw_sectors >> 1,
110 page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
111 ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
112
113 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
114 return -EINVAL;
115 /*
116 * Take the queue lock to update the readahead and max_sectors
117 * values synchronously:
118 */
119 spin_lock_irq(q->queue_lock);
120 q->max_sectors = max_sectors_kb << 1;
121 spin_unlock_irq(q->queue_lock);
122
123 return ret;
124}
125
126static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
127{
128 int max_hw_sectors_kb = q->max_hw_sectors >> 1;
129
130 return queue_var_show(max_hw_sectors_kb, (page));
131}
132
133
134static struct queue_sysfs_entry queue_requests_entry = {
135 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
136 .show = queue_requests_show,
137 .store = queue_requests_store,
138};
139
140static struct queue_sysfs_entry queue_ra_entry = {
141 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
142 .show = queue_ra_show,
143 .store = queue_ra_store,
144};
145
146static struct queue_sysfs_entry queue_max_sectors_entry = {
147 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
148 .show = queue_max_sectors_show,
149 .store = queue_max_sectors_store,
150};
151
152static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
153 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
154 .show = queue_max_hw_sectors_show,
155};
156
157static struct queue_sysfs_entry queue_iosched_entry = {
158 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
159 .show = elv_iosched_show,
160 .store = elv_iosched_store,
161};
162
163static struct attribute *default_attrs[] = {
164 &queue_requests_entry.attr,
165 &queue_ra_entry.attr,
166 &queue_max_hw_sectors_entry.attr,
167 &queue_max_sectors_entry.attr,
168 &queue_iosched_entry.attr,
169 NULL,
170};
171
172#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
173
174static ssize_t
175queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
176{
177 struct queue_sysfs_entry *entry = to_queue(attr);
178 struct request_queue *q =
179 container_of(kobj, struct request_queue, kobj);
180 ssize_t res;
181
182 if (!entry->show)
183 return -EIO;
184 mutex_lock(&q->sysfs_lock);
185 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
186 mutex_unlock(&q->sysfs_lock);
187 return -ENOENT;
188 }
189 res = entry->show(q, page);
190 mutex_unlock(&q->sysfs_lock);
191 return res;
192}
193
194static ssize_t
195queue_attr_store(struct kobject *kobj, struct attribute *attr,
196 const char *page, size_t length)
197{
198 struct queue_sysfs_entry *entry = to_queue(attr);
199 struct request_queue *q = container_of(kobj, struct request_queue, kobj);
200
201 ssize_t res;
202
203 if (!entry->store)
204 return -EIO;
205 mutex_lock(&q->sysfs_lock);
206 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
207 mutex_unlock(&q->sysfs_lock);
208 return -ENOENT;
209 }
210 res = entry->store(q, page, length);
211 mutex_unlock(&q->sysfs_lock);
212 return res;
213}
214
215/**
216 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
217 * @kobj: the kobj belonging of the request queue to be released
218 *
219 * Description:
220 * blk_cleanup_queue is the pair to blk_init_queue() or
221 * blk_queue_make_request(). It should be called when a request queue is
222 * being released; typically when a block device is being de-registered.
223 * Currently, its primary task it to free all the &struct request
224 * structures that were allocated to the queue and the queue itself.
225 *
226 * Caveat:
227 * Hopefully the low level driver will have finished any
228 * outstanding requests first...
229 **/
230static void blk_release_queue(struct kobject *kobj)
231{
232 struct request_queue *q =
233 container_of(kobj, struct request_queue, kobj);
234 struct request_list *rl = &q->rq;
235
236 blk_sync_queue(q);
237
238 if (rl->rq_pool)
239 mempool_destroy(rl->rq_pool);
240
241 if (q->queue_tags)
242 __blk_queue_free_tags(q);
243
244 blk_trace_shutdown(q);
245
246 bdi_destroy(&q->backing_dev_info);
247 kmem_cache_free(blk_requestq_cachep, q);
248}
249
250static struct sysfs_ops queue_sysfs_ops = {
251 .show = queue_attr_show,
252 .store = queue_attr_store,
253};
254
255struct kobj_type blk_queue_ktype = {
256 .sysfs_ops = &queue_sysfs_ops,
257 .default_attrs = default_attrs,
258 .release = blk_release_queue,
259};
260
261int blk_register_queue(struct gendisk *disk)
262{
263 int ret;
264
265 struct request_queue *q = disk->queue;
266
267 if (!q || !q->request_fn)
268 return -ENXIO;
269
270 ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
271 "%s", "queue");
272 if (ret < 0)
273 return ret;
274
275 kobject_uevent(&q->kobj, KOBJ_ADD);
276
277 ret = elv_register_queue(q);
278 if (ret) {
279 kobject_uevent(&q->kobj, KOBJ_REMOVE);
280 kobject_del(&q->kobj);
281 return ret;
282 }
283
284 return 0;
285}
286
287void blk_unregister_queue(struct gendisk *disk)
288{
289 struct request_queue *q = disk->queue;
290
291 if (q && q->request_fn) {
292 elv_unregister_queue(q);
293
294 kobject_uevent(&q->kobj, KOBJ_REMOVE);
295 kobject_del(&q->kobj);
296 kobject_put(&disk->dev.kobj);
297 }
298}
diff --git a/block/blk-tag.c b/block/blk-tag.c
new file mode 100644
index 000000000000..d1fd300e8aea
--- /dev/null
+++ b/block/blk-tag.c
@@ -0,0 +1,396 @@
1/*
2 * Functions related to tagged command queuing
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8
9/**
10 * blk_queue_find_tag - find a request by its tag and queue
11 * @q: The request queue for the device
12 * @tag: The tag of the request
13 *
14 * Notes:
15 * Should be used when a device returns a tag and you want to match
16 * it with a request.
17 *
18 * no locks need be held.
19 **/
20struct request *blk_queue_find_tag(struct request_queue *q, int tag)
21{
22 return blk_map_queue_find_tag(q->queue_tags, tag);
23}
24
25EXPORT_SYMBOL(blk_queue_find_tag);
26
27/**
28 * __blk_free_tags - release a given set of tag maintenance info
29 * @bqt: the tag map to free
30 *
31 * Tries to free the specified @bqt@. Returns true if it was
32 * actually freed and false if there are still references using it
33 */
34static int __blk_free_tags(struct blk_queue_tag *bqt)
35{
36 int retval;
37
38 retval = atomic_dec_and_test(&bqt->refcnt);
39 if (retval) {
40 BUG_ON(bqt->busy);
41
42 kfree(bqt->tag_index);
43 bqt->tag_index = NULL;
44
45 kfree(bqt->tag_map);
46 bqt->tag_map = NULL;
47
48 kfree(bqt);
49 }
50
51 return retval;
52}
53
54/**
55 * __blk_queue_free_tags - release tag maintenance info
56 * @q: the request queue for the device
57 *
58 * Notes:
59 * blk_cleanup_queue() will take care of calling this function, if tagging
60 * has been used. So there's no need to call this directly.
61 **/
62void __blk_queue_free_tags(struct request_queue *q)
63{
64 struct blk_queue_tag *bqt = q->queue_tags;
65
66 if (!bqt)
67 return;
68
69 __blk_free_tags(bqt);
70
71 q->queue_tags = NULL;
72 q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED);
73}
74
75/**
76 * blk_free_tags - release a given set of tag maintenance info
77 * @bqt: the tag map to free
78 *
79 * For externally managed @bqt@ frees the map. Callers of this
80 * function must guarantee to have released all the queues that
81 * might have been using this tag map.
82 */
83void blk_free_tags(struct blk_queue_tag *bqt)
84{
85 if (unlikely(!__blk_free_tags(bqt)))
86 BUG();
87}
88EXPORT_SYMBOL(blk_free_tags);
89
90/**
91 * blk_queue_free_tags - release tag maintenance info
92 * @q: the request queue for the device
93 *
94 * Notes:
95 * This is used to disabled tagged queuing to a device, yet leave
96 * queue in function.
97 **/
98void blk_queue_free_tags(struct request_queue *q)
99{
100 clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
101}
102
103EXPORT_SYMBOL(blk_queue_free_tags);
104
105static int
106init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth)
107{
108 struct request **tag_index;
109 unsigned long *tag_map;
110 int nr_ulongs;
111
112 if (q && depth > q->nr_requests * 2) {
113 depth = q->nr_requests * 2;
114 printk(KERN_ERR "%s: adjusted depth to %d\n",
115 __FUNCTION__, depth);
116 }
117
118 tag_index = kzalloc(depth * sizeof(struct request *), GFP_ATOMIC);
119 if (!tag_index)
120 goto fail;
121
122 nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
123 tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
124 if (!tag_map)
125 goto fail;
126
127 tags->real_max_depth = depth;
128 tags->max_depth = depth;
129 tags->tag_index = tag_index;
130 tags->tag_map = tag_map;
131
132 return 0;
133fail:
134 kfree(tag_index);
135 return -ENOMEM;
136}
137
138static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
139 int depth)
140{
141 struct blk_queue_tag *tags;
142
143 tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
144 if (!tags)
145 goto fail;
146
147 if (init_tag_map(q, tags, depth))
148 goto fail;
149
150 tags->busy = 0;
151 atomic_set(&tags->refcnt, 1);
152 return tags;
153fail:
154 kfree(tags);
155 return NULL;
156}
157
158/**
159 * blk_init_tags - initialize the tag info for an external tag map
160 * @depth: the maximum queue depth supported
161 * @tags: the tag to use
162 **/
163struct blk_queue_tag *blk_init_tags(int depth)
164{
165 return __blk_queue_init_tags(NULL, depth);
166}
167EXPORT_SYMBOL(blk_init_tags);
168
169/**
170 * blk_queue_init_tags - initialize the queue tag info
171 * @q: the request queue for the device
172 * @depth: the maximum queue depth supported
173 * @tags: the tag to use
174 **/
175int blk_queue_init_tags(struct request_queue *q, int depth,
176 struct blk_queue_tag *tags)
177{
178 int rc;
179
180 BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
181
182 if (!tags && !q->queue_tags) {
183 tags = __blk_queue_init_tags(q, depth);
184
185 if (!tags)
186 goto fail;
187 } else if (q->queue_tags) {
188 if ((rc = blk_queue_resize_tags(q, depth)))
189 return rc;
190 set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
191 return 0;
192 } else
193 atomic_inc(&tags->refcnt);
194
195 /*
196 * assign it, all done
197 */
198 q->queue_tags = tags;
199 q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
200 INIT_LIST_HEAD(&q->tag_busy_list);
201 return 0;
202fail:
203 kfree(tags);
204 return -ENOMEM;
205}
206
207EXPORT_SYMBOL(blk_queue_init_tags);
208
209/**
210 * blk_queue_resize_tags - change the queueing depth
211 * @q: the request queue for the device
212 * @new_depth: the new max command queueing depth
213 *
214 * Notes:
215 * Must be called with the queue lock held.
216 **/
217int blk_queue_resize_tags(struct request_queue *q, int new_depth)
218{
219 struct blk_queue_tag *bqt = q->queue_tags;
220 struct request **tag_index;
221 unsigned long *tag_map;
222 int max_depth, nr_ulongs;
223
224 if (!bqt)
225 return -ENXIO;
226
227 /*
228 * if we already have large enough real_max_depth. just
229 * adjust max_depth. *NOTE* as requests with tag value
230 * between new_depth and real_max_depth can be in-flight, tag
231 * map can not be shrunk blindly here.
232 */
233 if (new_depth <= bqt->real_max_depth) {
234 bqt->max_depth = new_depth;
235 return 0;
236 }
237
238 /*
239 * Currently cannot replace a shared tag map with a new
240 * one, so error out if this is the case
241 */
242 if (atomic_read(&bqt->refcnt) != 1)
243 return -EBUSY;
244
245 /*
246 * save the old state info, so we can copy it back
247 */
248 tag_index = bqt->tag_index;
249 tag_map = bqt->tag_map;
250 max_depth = bqt->real_max_depth;
251
252 if (init_tag_map(q, bqt, new_depth))
253 return -ENOMEM;
254
255 memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
256 nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
257 memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
258
259 kfree(tag_index);
260 kfree(tag_map);
261 return 0;
262}
263
264EXPORT_SYMBOL(blk_queue_resize_tags);
265
266/**
267 * blk_queue_end_tag - end tag operations for a request
268 * @q: the request queue for the device
269 * @rq: the request that has completed
270 *
271 * Description:
272 * Typically called when end_that_request_first() returns 0, meaning
273 * all transfers have been done for a request. It's important to call
274 * this function before end_that_request_last(), as that will put the
275 * request back on the free list thus corrupting the internal tag list.
276 *
277 * Notes:
278 * queue lock must be held.
279 **/
280void blk_queue_end_tag(struct request_queue *q, struct request *rq)
281{
282 struct blk_queue_tag *bqt = q->queue_tags;
283 int tag = rq->tag;
284
285 BUG_ON(tag == -1);
286
287 if (unlikely(tag >= bqt->real_max_depth))
288 /*
289 * This can happen after tag depth has been reduced.
290 * FIXME: how about a warning or info message here?
291 */
292 return;
293
294 list_del_init(&rq->queuelist);
295 rq->cmd_flags &= ~REQ_QUEUED;
296 rq->tag = -1;
297
298 if (unlikely(bqt->tag_index[tag] == NULL))
299 printk(KERN_ERR "%s: tag %d is missing\n",
300 __FUNCTION__, tag);
301
302 bqt->tag_index[tag] = NULL;
303
304 if (unlikely(!test_bit(tag, bqt->tag_map))) {
305 printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
306 __FUNCTION__, tag);
307 return;
308 }
309 /*
310 * The tag_map bit acts as a lock for tag_index[bit], so we need
311 * unlock memory barrier semantics.
312 */
313 clear_bit_unlock(tag, bqt->tag_map);
314 bqt->busy--;
315}
316
317EXPORT_SYMBOL(blk_queue_end_tag);
318
319/**
320 * blk_queue_start_tag - find a free tag and assign it
321 * @q: the request queue for the device
322 * @rq: the block request that needs tagging
323 *
324 * Description:
325 * This can either be used as a stand-alone helper, or possibly be
326 * assigned as the queue &prep_rq_fn (in which case &struct request
327 * automagically gets a tag assigned). Note that this function
328 * assumes that any type of request can be queued! if this is not
329 * true for your device, you must check the request type before
330 * calling this function. The request will also be removed from
331 * the request queue, so it's the drivers responsibility to readd
332 * it if it should need to be restarted for some reason.
333 *
334 * Notes:
335 * queue lock must be held.
336 **/
337int blk_queue_start_tag(struct request_queue *q, struct request *rq)
338{
339 struct blk_queue_tag *bqt = q->queue_tags;
340 int tag;
341
342 if (unlikely((rq->cmd_flags & REQ_QUEUED))) {
343 printk(KERN_ERR
344 "%s: request %p for device [%s] already tagged %d",
345 __FUNCTION__, rq,
346 rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
347 BUG();
348 }
349
350 /*
351 * Protect against shared tag maps, as we may not have exclusive
352 * access to the tag map.
353 */
354 do {
355 tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
356 if (tag >= bqt->max_depth)
357 return 1;
358
359 } while (test_and_set_bit_lock(tag, bqt->tag_map));
360 /*
361 * We need lock ordering semantics given by test_and_set_bit_lock.
362 * See blk_queue_end_tag for details.
363 */
364
365 rq->cmd_flags |= REQ_QUEUED;
366 rq->tag = tag;
367 bqt->tag_index[tag] = rq;
368 blkdev_dequeue_request(rq);
369 list_add(&rq->queuelist, &q->tag_busy_list);
370 bqt->busy++;
371 return 0;
372}
373
374EXPORT_SYMBOL(blk_queue_start_tag);
375
376/**
377 * blk_queue_invalidate_tags - invalidate all pending tags
378 * @q: the request queue for the device
379 *
380 * Description:
381 * Hardware conditions may dictate a need to stop all pending requests.
382 * In this case, we will safely clear the block side of the tag queue and
383 * readd all requests to the request queue in the right order.
384 *
385 * Notes:
386 * queue lock must be held.
387 **/
388void blk_queue_invalidate_tags(struct request_queue *q)
389{
390 struct list_head *tmp, *n;
391
392 list_for_each_safe(tmp, n, &q->tag_busy_list)
393 blk_requeue_request(q, list_entry_rq(tmp));
394}
395
396EXPORT_SYMBOL(blk_queue_invalidate_tags);
diff --git a/block/blk.h b/block/blk.h
new file mode 100644
index 000000000000..d88549df1b09
--- /dev/null
+++ b/block/blk.h
@@ -0,0 +1,29 @@
1#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
4extern struct kmem_cache *blk_requestq_cachep;
5extern struct kobj_type blk_queue_ktype;
6
7void __blk_queue_free_tags(struct request_queue *q);
8
9void blk_queue_congestion_threshold(struct request_queue *q);
10
11/*
12 * Return the threshold (number of used requests) at which the queue is
13 * considered to be congested. It include a little hysteresis to keep the
14 * context switch rate down.
15 */
16static inline int queue_congestion_on_threshold(struct request_queue *q)
17{
18 return q->nr_congestion_on;
19}
20
21/*
22 * The threshold at which a queue is considered to be uncongested
23 */
24static inline int queue_congestion_off_threshold(struct request_queue *q)
25{
26 return q->nr_congestion_off;
27}
28
29#endif
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-10 10:54:17 -0500