Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 3 | * Copyright (C) 1994, Karl Keyte: Added support for disk statistics |
| 4 | * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| 5 | * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
| 7 | * - July2000 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 |
| 9 | */ |
| 10 | |
| 11 | /* |
| 12 | * This handles all read/write requests to block devices |
| 13 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/kernel.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/backing-dev.h> |
| 17 | #include <linux/bio.h> |
| 18 | #include <linux/blkdev.h> |
| 19 | #include <linux/highmem.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/kernel_stat.h> |
| 22 | #include <linux/string.h> |
| 23 | #include <linux/init.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/completion.h> |
| 25 | #include <linux/slab.h> |
| 26 | #include <linux/swap.h> |
| 27 | #include <linux/writeback.h> |
Andrew Morton | faccbd4 | 2006-12-10 02:19:35 -0800 | [diff] [blame] | 28 | #include <linux/task_io_accounting_ops.h> |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 29 | #include <linux/blktrace_api.h> |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 30 | #include <linux/fault-inject.h> |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 31 | #include <trace/block.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 33 | #include "blk.h" |
| 34 | |
Ingo Molnar | 0bfc245 | 2008-11-26 11:59:56 +0100 | [diff] [blame] | 35 | DEFINE_TRACE(block_plug); |
| 36 | DEFINE_TRACE(block_unplug_io); |
| 37 | DEFINE_TRACE(block_unplug_timer); |
| 38 | DEFINE_TRACE(block_getrq); |
| 39 | DEFINE_TRACE(block_sleeprq); |
| 40 | DEFINE_TRACE(block_rq_requeue); |
| 41 | DEFINE_TRACE(block_bio_backmerge); |
| 42 | DEFINE_TRACE(block_bio_frontmerge); |
| 43 | DEFINE_TRACE(block_bio_queue); |
| 44 | DEFINE_TRACE(block_rq_complete); |
| 45 | DEFINE_TRACE(block_remap); /* Also used in drivers/md/dm.c */ |
| 46 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap); |
| 47 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 48 | static int __make_request(struct request_queue *q, struct bio *bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | |
| 50 | /* |
| 51 | * For the allocated request tables |
| 52 | */ |
Adrian Bunk | 5ece6c5 | 2008-02-18 13:45:51 +0100 | [diff] [blame] | 53 | static struct kmem_cache *request_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | |
| 55 | /* |
| 56 | * For queue allocation |
| 57 | */ |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 58 | struct kmem_cache *blk_requestq_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | |
| 60 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | * Controlling structure to kblockd |
| 62 | */ |
Jens Axboe | ff856ba | 2006-01-09 16:02:34 +0100 | [diff] [blame] | 63 | static struct workqueue_struct *kblockd_workqueue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 65 | static void drive_stat_acct(struct request *rq, int new_io) |
| 66 | { |
Jens Axboe | 28f1370 | 2008-05-07 10:15:46 +0200 | [diff] [blame] | 67 | struct hd_struct *part; |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 68 | int rw = rq_data_dir(rq); |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 69 | int cpu; |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 70 | |
Jerome Marchand | 26308ea | 2009-03-27 10:31:51 +0100 | [diff] [blame] | 71 | if (!blk_fs_request(rq) || !blk_do_io_stat(rq)) |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 72 | return; |
| 73 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 74 | cpu = part_stat_lock(); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 75 | part = disk_map_sector_rcu(rq->rq_disk, rq->sector); |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 76 | |
Jens Axboe | 28f1370 | 2008-05-07 10:15:46 +0200 | [diff] [blame] | 77 | if (!new_io) |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 78 | part_stat_inc(cpu, part, merges[rw]); |
Jens Axboe | 28f1370 | 2008-05-07 10:15:46 +0200 | [diff] [blame] | 79 | else { |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 80 | part_round_stats(cpu, part); |
| 81 | part_inc_in_flight(part); |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 82 | } |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 83 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 84 | part_stat_unlock(); |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 85 | } |
| 86 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 87 | void blk_queue_congestion_threshold(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | { |
| 89 | int nr; |
| 90 | |
| 91 | nr = q->nr_requests - (q->nr_requests / 8) + 1; |
| 92 | if (nr > q->nr_requests) |
| 93 | nr = q->nr_requests; |
| 94 | q->nr_congestion_on = nr; |
| 95 | |
| 96 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; |
| 97 | if (nr < 1) |
| 98 | nr = 1; |
| 99 | q->nr_congestion_off = nr; |
| 100 | } |
| 101 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | /** |
| 103 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info |
| 104 | * @bdev: device |
| 105 | * |
| 106 | * Locates the passed device's request queue and returns the address of its |
| 107 | * backing_dev_info |
| 108 | * |
| 109 | * Will return NULL if the request queue cannot be located. |
| 110 | */ |
| 111 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) |
| 112 | { |
| 113 | struct backing_dev_info *ret = NULL; |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 114 | struct request_queue *q = bdev_get_queue(bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | |
| 116 | if (q) |
| 117 | ret = &q->backing_dev_info; |
| 118 | return ret; |
| 119 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | EXPORT_SYMBOL(blk_get_backing_dev_info); |
| 121 | |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 122 | void blk_rq_init(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | { |
FUJITA Tomonori | 1afb20f | 2008-04-25 12:26:28 +0200 | [diff] [blame] | 124 | memset(rq, 0, sizeof(*rq)); |
| 125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | INIT_LIST_HEAD(&rq->queuelist); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 127 | INIT_LIST_HEAD(&rq->timeout_list); |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 128 | rq->cpu = -1; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 129 | rq->q = q; |
| 130 | rq->sector = rq->hard_sector = (sector_t) -1; |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 131 | INIT_HLIST_NODE(&rq->hash); |
| 132 | RB_CLEAR_NODE(&rq->rb_node); |
FUJITA Tomonori | d7e3c32 | 2008-04-29 09:54:39 +0200 | [diff] [blame] | 133 | rq->cmd = rq->__cmd; |
Li Zefan | e2494e1 | 2009-04-02 13:43:26 +0800 | [diff] [blame] | 134 | rq->cmd_len = BLK_MAX_CDB; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 135 | rq->tag = -1; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 136 | rq->ref_count = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | } |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 138 | EXPORT_SYMBOL(blk_rq_init); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 140 | static void req_bio_endio(struct request *rq, struct bio *bio, |
| 141 | unsigned int nbytes, int error) |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 142 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 143 | struct request_queue *q = rq->q; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 144 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 145 | if (&q->bar_rq != rq) { |
| 146 | if (error) |
| 147 | clear_bit(BIO_UPTODATE, &bio->bi_flags); |
| 148 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) |
| 149 | error = -EIO; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 150 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 151 | if (unlikely(nbytes > bio->bi_size)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 152 | printk(KERN_ERR "%s: want %u bytes done, %u left\n", |
Harvey Harrison | 24c03d4 | 2008-05-01 04:35:17 -0700 | [diff] [blame] | 153 | __func__, nbytes, bio->bi_size); |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 154 | nbytes = bio->bi_size; |
| 155 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 156 | |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 157 | if (unlikely(rq->cmd_flags & REQ_QUIET)) |
| 158 | set_bit(BIO_QUIET, &bio->bi_flags); |
| 159 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 160 | bio->bi_size -= nbytes; |
| 161 | bio->bi_sector += (nbytes >> 9); |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 162 | |
| 163 | if (bio_integrity(bio)) |
| 164 | bio_integrity_advance(bio, nbytes); |
| 165 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 166 | if (bio->bi_size == 0) |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 167 | bio_endio(bio, error); |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 168 | } else { |
| 169 | |
| 170 | /* |
| 171 | * Okay, this is the barrier request in progress, just |
| 172 | * record the error; |
| 173 | */ |
| 174 | if (error && !q->orderr) |
| 175 | q->orderr = error; |
| 176 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 177 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | void blk_dump_rq_flags(struct request *rq, char *msg) |
| 180 | { |
| 181 | int bit; |
| 182 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 183 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%x\n", msg, |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 184 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, |
| 185 | rq->cmd_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 187 | printk(KERN_INFO " sector %llu, nr/cnr %lu/%u\n", |
| 188 | (unsigned long long)rq->sector, |
| 189 | rq->nr_sectors, |
| 190 | rq->current_nr_sectors); |
| 191 | printk(KERN_INFO " bio %p, biotail %p, buffer %p, data %p, len %u\n", |
| 192 | rq->bio, rq->biotail, |
| 193 | rq->buffer, rq->data, |
| 194 | rq->data_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 196 | if (blk_pc_request(rq)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 197 | printk(KERN_INFO " cdb: "); |
FUJITA Tomonori | d34c87e | 2008-04-29 14:37:52 +0200 | [diff] [blame] | 198 | for (bit = 0; bit < BLK_MAX_CDB; bit++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | printk("%02x ", rq->cmd[bit]); |
| 200 | printk("\n"); |
| 201 | } |
| 202 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | EXPORT_SYMBOL(blk_dump_rq_flags); |
| 204 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | /* |
| 206 | * "plug" the device if there are no outstanding requests: this will |
| 207 | * force the transfer to start only after we have put all the requests |
| 208 | * on the list. |
| 209 | * |
| 210 | * This is called with interrupts off and no requests on the queue and |
| 211 | * with the queue lock held. |
| 212 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 213 | void blk_plug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | { |
| 215 | WARN_ON(!irqs_disabled()); |
| 216 | |
| 217 | /* |
| 218 | * don't plug a stopped queue, it must be paired with blk_start_queue() |
| 219 | * which will restart the queueing |
| 220 | */ |
Coywolf Qi Hunt | 7daac49 | 2006-04-19 10:14:49 +0200 | [diff] [blame] | 221 | if (blk_queue_stopped(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | return; |
| 223 | |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 224 | if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 226 | trace_block_plug(q); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 227 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | EXPORT_SYMBOL(blk_plug_device); |
| 230 | |
Jens Axboe | 6c5e0c4 | 2008-08-01 20:31:32 +0200 | [diff] [blame] | 231 | /** |
| 232 | * blk_plug_device_unlocked - plug a device without queue lock held |
| 233 | * @q: The &struct request_queue to plug |
| 234 | * |
| 235 | * Description: |
| 236 | * Like @blk_plug_device(), but grabs the queue lock and disables |
| 237 | * interrupts. |
| 238 | **/ |
| 239 | void blk_plug_device_unlocked(struct request_queue *q) |
| 240 | { |
| 241 | unsigned long flags; |
| 242 | |
| 243 | spin_lock_irqsave(q->queue_lock, flags); |
| 244 | blk_plug_device(q); |
| 245 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 246 | } |
| 247 | EXPORT_SYMBOL(blk_plug_device_unlocked); |
| 248 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | /* |
| 250 | * remove the queue from the plugged list, if present. called with |
| 251 | * queue lock held and interrupts disabled. |
| 252 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 253 | int blk_remove_plug(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | { |
| 255 | WARN_ON(!irqs_disabled()); |
| 256 | |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 257 | if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | return 0; |
| 259 | |
| 260 | del_timer(&q->unplug_timer); |
| 261 | return 1; |
| 262 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | EXPORT_SYMBOL(blk_remove_plug); |
| 264 | |
| 265 | /* |
| 266 | * remove the plug and let it rip.. |
| 267 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 268 | void __generic_unplug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | { |
Coywolf Qi Hunt | 7daac49 | 2006-04-19 10:14:49 +0200 | [diff] [blame] | 270 | if (unlikely(blk_queue_stopped(q))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | return; |
Jens Axboe | a31a973 | 2008-10-17 13:58:29 +0200 | [diff] [blame] | 272 | if (!blk_remove_plug(q) && !blk_queue_nonrot(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | return; |
| 274 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 275 | q->request_fn(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | |
| 278 | /** |
| 279 | * generic_unplug_device - fire a request queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 280 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | * |
| 282 | * Description: |
| 283 | * Linux uses plugging to build bigger requests queues before letting |
| 284 | * the device have at them. If a queue is plugged, the I/O scheduler |
| 285 | * is still adding and merging requests on the queue. Once the queue |
| 286 | * gets unplugged, the request_fn defined for the queue is invoked and |
| 287 | * transfers started. |
| 288 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 289 | void generic_unplug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | { |
Jens Axboe | dbaf2c0 | 2008-05-07 09:48:17 +0200 | [diff] [blame] | 291 | if (blk_queue_plugged(q)) { |
| 292 | spin_lock_irq(q->queue_lock); |
| 293 | __generic_unplug_device(q); |
| 294 | spin_unlock_irq(q->queue_lock); |
| 295 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | } |
| 297 | EXPORT_SYMBOL(generic_unplug_device); |
| 298 | |
| 299 | static void blk_backing_dev_unplug(struct backing_dev_info *bdi, |
| 300 | struct page *page) |
| 301 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 302 | struct request_queue *q = bdi->unplug_io_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 303 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 304 | blk_unplug(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | } |
| 306 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 307 | void blk_unplug_work(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 308 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 309 | struct request_queue *q = |
| 310 | container_of(work, struct request_queue, unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 312 | trace_block_unplug_io(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | q->unplug_fn(q); |
| 314 | } |
| 315 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 316 | void blk_unplug_timeout(unsigned long data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 318 | struct request_queue *q = (struct request_queue *)data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 320 | trace_block_unplug_timer(q); |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame] | 321 | kblockd_schedule_work(q, &q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | } |
| 323 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 324 | void blk_unplug(struct request_queue *q) |
| 325 | { |
| 326 | /* |
| 327 | * devices don't necessarily have an ->unplug_fn defined |
| 328 | */ |
| 329 | if (q->unplug_fn) { |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 330 | trace_block_unplug_io(q); |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 331 | q->unplug_fn(q); |
| 332 | } |
| 333 | } |
| 334 | EXPORT_SYMBOL(blk_unplug); |
| 335 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | /** |
| 337 | * blk_start_queue - restart a previously stopped queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 338 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | * |
| 340 | * Description: |
| 341 | * blk_start_queue() will clear the stop flag on the queue, and call |
| 342 | * the request_fn for the queue if it was in a stopped state when |
| 343 | * entered. Also see blk_stop_queue(). Queue lock must be held. |
| 344 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 345 | void blk_start_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | { |
Paolo 'Blaisorblade' Giarrusso | a038e25 | 2006-06-05 12:09:01 +0200 | [diff] [blame] | 347 | WARN_ON(!irqs_disabled()); |
| 348 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 349 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
Tejun Heo | a538cd0 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 350 | __blk_run_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | EXPORT_SYMBOL(blk_start_queue); |
| 353 | |
| 354 | /** |
| 355 | * blk_stop_queue - stop a queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 356 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | * |
| 358 | * Description: |
| 359 | * The Linux block layer assumes that a block driver will consume all |
| 360 | * entries on the request queue when the request_fn strategy is called. |
| 361 | * Often this will not happen, because of hardware limitations (queue |
| 362 | * depth settings). If a device driver gets a 'queue full' response, |
| 363 | * or if it simply chooses not to queue more I/O at one point, it can |
| 364 | * call this function to prevent the request_fn from being called until |
| 365 | * the driver has signalled it's ready to go again. This happens by calling |
| 366 | * blk_start_queue() to restart queue operations. Queue lock must be held. |
| 367 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 368 | void blk_stop_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | { |
| 370 | blk_remove_plug(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 371 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | } |
| 373 | EXPORT_SYMBOL(blk_stop_queue); |
| 374 | |
| 375 | /** |
| 376 | * blk_sync_queue - cancel any pending callbacks on a queue |
| 377 | * @q: the queue |
| 378 | * |
| 379 | * Description: |
| 380 | * The block layer may perform asynchronous callback activity |
| 381 | * on a queue, such as calling the unplug function after a timeout. |
| 382 | * A block device may call blk_sync_queue to ensure that any |
| 383 | * such activity is cancelled, thus allowing it to release resources |
Michael Opdenacker | 59c5159 | 2007-05-09 08:57:56 +0200 | [diff] [blame] | 384 | * that the callbacks might use. The caller must already have made sure |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | * that its ->make_request_fn will not re-add plugging prior to calling |
| 386 | * this function. |
| 387 | * |
| 388 | */ |
| 389 | void blk_sync_queue(struct request_queue *q) |
| 390 | { |
| 391 | del_timer_sync(&q->unplug_timer); |
Jens Axboe | 70ed28b | 2008-11-19 14:38:39 +0100 | [diff] [blame] | 392 | del_timer_sync(&q->timeout); |
Cheng Renquan | 64d01dc | 2008-12-03 12:41:39 +0100 | [diff] [blame] | 393 | cancel_work_sync(&q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | } |
| 395 | EXPORT_SYMBOL(blk_sync_queue); |
| 396 | |
| 397 | /** |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 398 | * __blk_run_queue - run a single device queue |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | * @q: The queue to run |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 400 | * |
| 401 | * Description: |
| 402 | * See @blk_run_queue. This variant must be called with the queue lock |
| 403 | * held and interrupts disabled. |
| 404 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | */ |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 406 | void __blk_run_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | blk_remove_plug(q); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 409 | |
Tejun Heo | a538cd0 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 410 | if (unlikely(blk_queue_stopped(q))) |
| 411 | return; |
| 412 | |
| 413 | if (elv_queue_empty(q)) |
| 414 | return; |
| 415 | |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 416 | /* |
| 417 | * Only recurse once to avoid overrunning the stack, let the unplug |
| 418 | * handling reinvoke the handler shortly if we already got there. |
| 419 | */ |
Tejun Heo | a538cd0 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 420 | if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { |
| 421 | q->request_fn(q); |
| 422 | queue_flag_clear(QUEUE_FLAG_REENTER, q); |
| 423 | } else { |
| 424 | queue_flag_set(QUEUE_FLAG_PLUGGED, q); |
| 425 | kblockd_schedule_work(q, &q->unplug_work); |
| 426 | } |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 427 | } |
| 428 | EXPORT_SYMBOL(__blk_run_queue); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 429 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 430 | /** |
| 431 | * blk_run_queue - run a single device queue |
| 432 | * @q: The queue to run |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 433 | * |
| 434 | * Description: |
| 435 | * Invoke request handling on this queue, if it has pending work to do. |
Tejun Heo | a7f5579 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 436 | * May be used to restart queueing when a request has completed. |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 437 | */ |
| 438 | void blk_run_queue(struct request_queue *q) |
| 439 | { |
| 440 | unsigned long flags; |
| 441 | |
| 442 | spin_lock_irqsave(q->queue_lock, flags); |
| 443 | __blk_run_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 445 | } |
| 446 | EXPORT_SYMBOL(blk_run_queue); |
| 447 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 448 | void blk_put_queue(struct request_queue *q) |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 449 | { |
| 450 | kobject_put(&q->kobj); |
| 451 | } |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 452 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 453 | void blk_cleanup_queue(struct request_queue *q) |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 454 | { |
Jens Axboe | e3335de | 2008-09-18 09:22:54 -0700 | [diff] [blame] | 455 | /* |
| 456 | * We know we have process context here, so we can be a little |
| 457 | * cautious and ensure that pending block actions on this device |
| 458 | * are done before moving on. Going into this function, we should |
| 459 | * not have processes doing IO to this device. |
| 460 | */ |
| 461 | blk_sync_queue(q); |
| 462 | |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 463 | mutex_lock(&q->sysfs_lock); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 464 | queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 465 | mutex_unlock(&q->sysfs_lock); |
| 466 | |
| 467 | if (q->elevator) |
| 468 | elevator_exit(q->elevator); |
| 469 | |
| 470 | blk_put_queue(q); |
| 471 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | EXPORT_SYMBOL(blk_cleanup_queue); |
| 473 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 474 | static int blk_init_free_list(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | { |
| 476 | struct request_list *rl = &q->rq; |
| 477 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 478 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
| 479 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 480 | rl->elvpriv = 0; |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 481 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
| 482 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 484 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
| 485 | mempool_free_slab, request_cachep, q->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | |
| 487 | if (!rl->rq_pool) |
| 488 | return -ENOMEM; |
| 489 | |
| 490 | return 0; |
| 491 | } |
| 492 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 493 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | { |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 495 | return blk_alloc_queue_node(gfp_mask, -1); |
| 496 | } |
| 497 | EXPORT_SYMBOL(blk_alloc_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 499 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 500 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 501 | struct request_queue *q; |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 502 | int err; |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 503 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 504 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 505 | gfp_mask | __GFP_ZERO, node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | if (!q) |
| 507 | return NULL; |
| 508 | |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 509 | q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; |
| 510 | q->backing_dev_info.unplug_io_data = q; |
| 511 | err = bdi_init(&q->backing_dev_info); |
| 512 | if (err) { |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 513 | kmem_cache_free(blk_requestq_cachep, q); |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 514 | return NULL; |
| 515 | } |
| 516 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | init_timer(&q->unplug_timer); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 518 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); |
| 519 | INIT_LIST_HEAD(&q->timeout_list); |
Peter Zijlstra | 713ada9 | 2008-10-16 13:44:57 +0200 | [diff] [blame] | 520 | INIT_WORK(&q->unplug_work, blk_unplug_work); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 521 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 522 | kobject_init(&q->kobj, &blk_queue_ktype); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 524 | mutex_init(&q->sysfs_lock); |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 525 | spin_lock_init(&q->__queue_lock); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 526 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | return q; |
| 528 | } |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 529 | EXPORT_SYMBOL(blk_alloc_queue_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | |
| 531 | /** |
| 532 | * blk_init_queue - prepare a request queue for use with a block device |
| 533 | * @rfn: The function to be called to process requests that have been |
| 534 | * placed on the queue. |
| 535 | * @lock: Request queue spin lock |
| 536 | * |
| 537 | * Description: |
| 538 | * If a block device wishes to use the standard request handling procedures, |
| 539 | * which sorts requests and coalesces adjacent requests, then it must |
| 540 | * call blk_init_queue(). The function @rfn will be called when there |
| 541 | * are requests on the queue that need to be processed. If the device |
| 542 | * supports plugging, then @rfn may not be called immediately when requests |
| 543 | * are available on the queue, but may be called at some time later instead. |
| 544 | * Plugged queues are generally unplugged when a buffer belonging to one |
| 545 | * of the requests on the queue is needed, or due to memory pressure. |
| 546 | * |
| 547 | * @rfn is not required, or even expected, to remove all requests off the |
| 548 | * queue, but only as many as it can handle at a time. If it does leave |
| 549 | * requests on the queue, it is responsible for arranging that the requests |
| 550 | * get dealt with eventually. |
| 551 | * |
| 552 | * The queue spin lock must be held while manipulating the requests on the |
Paolo 'Blaisorblade' Giarrusso | a038e25 | 2006-06-05 12:09:01 +0200 | [diff] [blame] | 553 | * request queue; this lock will be taken also from interrupt context, so irq |
| 554 | * disabling is needed for it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 556 | * Function returns a pointer to the initialized request queue, or %NULL if |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | * it didn't succeed. |
| 558 | * |
| 559 | * Note: |
| 560 | * blk_init_queue() must be paired with a blk_cleanup_queue() call |
| 561 | * when the block device is deactivated (such as at module unload). |
| 562 | **/ |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 563 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 564 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | { |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 566 | return blk_init_queue_node(rfn, lock, -1); |
| 567 | } |
| 568 | EXPORT_SYMBOL(blk_init_queue); |
| 569 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 570 | struct request_queue * |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 571 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
| 572 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 573 | struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | |
| 575 | if (!q) |
| 576 | return NULL; |
| 577 | |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 578 | q->node = node_id; |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 579 | if (blk_init_free_list(q)) { |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 580 | kmem_cache_free(blk_requestq_cachep, q); |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 581 | return NULL; |
| 582 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 583 | |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 584 | /* |
| 585 | * if caller didn't supply a lock, they get per-queue locking with |
| 586 | * our embedded lock |
| 587 | */ |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 588 | if (!lock) |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 589 | lock = &q->__queue_lock; |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 590 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | q->request_fn = rfn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | q->prep_rq_fn = NULL; |
| 593 | q->unplug_fn = generic_unplug_device; |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 594 | q->queue_flags = QUEUE_FLAG_DEFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | q->queue_lock = lock; |
| 596 | |
Jens Axboe | f3b144a | 2009-03-06 08:48:33 +0100 | [diff] [blame] | 597 | /* |
| 598 | * This also sets hw/phys segments, boundary and size |
| 599 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | blk_queue_make_request(q, __make_request); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | |
Alan Stern | 44ec954 | 2007-02-20 11:01:57 -0500 | [diff] [blame] | 602 | q->sg_reserved_size = INT_MAX; |
| 603 | |
FUJITA Tomonori | abf5439 | 2008-08-16 14:10:05 +0900 | [diff] [blame] | 604 | blk_set_cmd_filter_defaults(&q->cmd_filter); |
| 605 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | /* |
| 607 | * all done |
| 608 | */ |
| 609 | if (!elevator_init(q, NULL)) { |
| 610 | blk_queue_congestion_threshold(q); |
| 611 | return q; |
| 612 | } |
| 613 | |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 614 | blk_put_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 615 | return NULL; |
| 616 | } |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 617 | EXPORT_SYMBOL(blk_init_queue_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 618 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 619 | int blk_get_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | { |
Nick Piggin | fde6ad2 | 2005-06-23 00:08:53 -0700 | [diff] [blame] | 621 | if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 622 | kobject_get(&q->kobj); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | return 0; |
| 624 | } |
| 625 | |
| 626 | return 1; |
| 627 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 629 | static inline void blk_free_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | { |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 631 | if (rq->cmd_flags & REQ_ELVPRIV) |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 632 | elv_put_request(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | mempool_free(rq, q->rq.rq_pool); |
| 634 | } |
| 635 | |
Jens Axboe | 1ea25ec | 2006-07-18 22:24:11 +0200 | [diff] [blame] | 636 | static struct request * |
Jerome Marchand | 42dad76 | 2009-04-22 14:01:49 +0200 | [diff] [blame] | 637 | blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 638 | { |
| 639 | struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); |
| 640 | |
| 641 | if (!rq) |
| 642 | return NULL; |
| 643 | |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 644 | blk_rq_init(q, rq); |
FUJITA Tomonori | 1afb20f | 2008-04-25 12:26:28 +0200 | [diff] [blame] | 645 | |
Jerome Marchand | 42dad76 | 2009-04-22 14:01:49 +0200 | [diff] [blame] | 646 | rq->cmd_flags = flags | REQ_ALLOCED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 648 | if (priv) { |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 649 | if (unlikely(elv_set_request(q, rq, gfp_mask))) { |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 650 | mempool_free(rq, q->rq.rq_pool); |
| 651 | return NULL; |
| 652 | } |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 653 | rq->cmd_flags |= REQ_ELVPRIV; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 654 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 656 | return rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | } |
| 658 | |
| 659 | /* |
| 660 | * ioc_batching returns true if the ioc is a valid batching request and |
| 661 | * should be given priority access to a request. |
| 662 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 663 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | { |
| 665 | if (!ioc) |
| 666 | return 0; |
| 667 | |
| 668 | /* |
| 669 | * Make sure the process is able to allocate at least 1 request |
| 670 | * even if the batch times out, otherwise we could theoretically |
| 671 | * lose wakeups. |
| 672 | */ |
| 673 | return ioc->nr_batch_requests == q->nr_batching || |
| 674 | (ioc->nr_batch_requests > 0 |
| 675 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); |
| 676 | } |
| 677 | |
| 678 | /* |
| 679 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This |
| 680 | * will cause the process to be a "batcher" on all queues in the system. This |
| 681 | * is the behaviour we want though - once it gets a wakeup it should be given |
| 682 | * a nice run. |
| 683 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 684 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | { |
| 686 | if (!ioc || ioc_batching(q, ioc)) |
| 687 | return; |
| 688 | |
| 689 | ioc->nr_batch_requests = q->nr_batching; |
| 690 | ioc->last_waited = jiffies; |
| 691 | } |
| 692 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 693 | static void __freed_request(struct request_queue *q, int sync) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | { |
| 695 | struct request_list *rl = &q->rq; |
| 696 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 697 | if (rl->count[sync] < queue_congestion_off_threshold(q)) |
| 698 | blk_clear_queue_congested(q, sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 699 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 700 | if (rl->count[sync] + 1 <= q->nr_requests) { |
| 701 | if (waitqueue_active(&rl->wait[sync])) |
| 702 | wake_up(&rl->wait[sync]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 704 | blk_clear_queue_full(q, sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | } |
| 706 | } |
| 707 | |
| 708 | /* |
| 709 | * A request has just been released. Account for it, update the full and |
| 710 | * congestion status, wake up any waiters. Called under q->queue_lock. |
| 711 | */ |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 712 | static void freed_request(struct request_queue *q, int sync, int priv) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | { |
| 714 | struct request_list *rl = &q->rq; |
| 715 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 716 | rl->count[sync]--; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 717 | if (priv) |
| 718 | rl->elvpriv--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 719 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 720 | __freed_request(q, sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 722 | if (unlikely(rl->starved[sync ^ 1])) |
| 723 | __freed_request(q, sync ^ 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | } |
| 725 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | /* |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 727 | * Get a free request, queue_lock must be held. |
| 728 | * Returns NULL on failure, with queue_lock held. |
| 729 | * Returns !NULL on success, with queue_lock *not held*. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 730 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 731 | static struct request *get_request(struct request_queue *q, int rw_flags, |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 732 | struct bio *bio, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | { |
| 734 | struct request *rq = NULL; |
| 735 | struct request_list *rl = &q->rq; |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 736 | struct io_context *ioc = NULL; |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 737 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 738 | int may_queue, priv; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 739 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 740 | may_queue = elv_may_queue(q, rw_flags); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 741 | if (may_queue == ELV_MQUEUE_NO) |
| 742 | goto rq_starved; |
| 743 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 744 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
| 745 | if (rl->count[is_sync]+1 >= q->nr_requests) { |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 746 | ioc = current_io_context(GFP_ATOMIC, q->node); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 747 | /* |
| 748 | * The queue will fill after this allocation, so set |
| 749 | * it as full, and mark this process as "batching". |
| 750 | * This process will be allowed to complete a batch of |
| 751 | * requests, others will be blocked. |
| 752 | */ |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 753 | if (!blk_queue_full(q, is_sync)) { |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 754 | ioc_set_batching(q, ioc); |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 755 | blk_set_queue_full(q, is_sync); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 756 | } else { |
| 757 | if (may_queue != ELV_MQUEUE_MUST |
| 758 | && !ioc_batching(q, ioc)) { |
| 759 | /* |
| 760 | * The queue is full and the allocating |
| 761 | * process is not a "batcher", and not |
| 762 | * exempted by the IO scheduler |
| 763 | */ |
| 764 | goto out; |
| 765 | } |
| 766 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | } |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 768 | blk_set_queue_congested(q, is_sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | } |
| 770 | |
Jens Axboe | 082cf69 | 2005-06-28 16:35:11 +0200 | [diff] [blame] | 771 | /* |
| 772 | * Only allow batching queuers to allocate up to 50% over the defined |
| 773 | * limit of requests, otherwise we could have thousands of requests |
| 774 | * allocated with any setting of ->nr_requests |
| 775 | */ |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 776 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
Jens Axboe | 082cf69 | 2005-06-28 16:35:11 +0200 | [diff] [blame] | 777 | goto out; |
Hugh Dickins | fd782a4 | 2005-06-29 15:15:40 +0100 | [diff] [blame] | 778 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 779 | rl->count[is_sync]++; |
| 780 | rl->starved[is_sync] = 0; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 781 | |
Jens Axboe | 64521d1 | 2005-10-28 08:30:39 +0200 | [diff] [blame] | 782 | priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 783 | if (priv) |
| 784 | rl->elvpriv++; |
| 785 | |
Jerome Marchand | 42dad76 | 2009-04-22 14:01:49 +0200 | [diff] [blame] | 786 | if (blk_queue_io_stat(q)) |
| 787 | rw_flags |= REQ_IO_STAT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 788 | spin_unlock_irq(q->queue_lock); |
| 789 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 790 | rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 791 | if (unlikely(!rq)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 792 | /* |
| 793 | * Allocation failed presumably due to memory. Undo anything |
| 794 | * we might have messed up. |
| 795 | * |
| 796 | * Allocating task should really be put onto the front of the |
| 797 | * wait queue, but this is pretty rare. |
| 798 | */ |
| 799 | spin_lock_irq(q->queue_lock); |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 800 | freed_request(q, is_sync, priv); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | |
| 802 | /* |
| 803 | * in the very unlikely event that allocation failed and no |
| 804 | * requests for this direction was pending, mark us starved |
| 805 | * so that freeing of a request in the other direction will |
| 806 | * notice us. another possible fix would be to split the |
| 807 | * rq mempool into READ and WRITE |
| 808 | */ |
| 809 | rq_starved: |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 810 | if (unlikely(rl->count[is_sync] == 0)) |
| 811 | rl->starved[is_sync] = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 812 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | goto out; |
| 814 | } |
| 815 | |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 816 | /* |
| 817 | * ioc may be NULL here, and ioc_batching will be false. That's |
| 818 | * OK, if the queue is under the request limit then requests need |
| 819 | * not count toward the nr_batch_requests limit. There will always |
| 820 | * be some limit enforced by BLK_BATCH_TIME. |
| 821 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 822 | if (ioc_batching(q, ioc)) |
| 823 | ioc->nr_batch_requests--; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 824 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 825 | trace_block_getrq(q, bio, rw_flags & 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | return rq; |
| 828 | } |
| 829 | |
| 830 | /* |
| 831 | * No available requests for this queue, unplug the device and wait for some |
| 832 | * requests to become available. |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 833 | * |
| 834 | * Called with q->queue_lock held, and returns with it unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 835 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 836 | static struct request *get_request_wait(struct request_queue *q, int rw_flags, |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 837 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 838 | { |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 839 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | struct request *rq; |
| 841 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 842 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 843 | while (!rq) { |
| 844 | DEFINE_WAIT(wait); |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 845 | struct io_context *ioc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | struct request_list *rl = &q->rq; |
| 847 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 848 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 849 | TASK_UNINTERRUPTIBLE); |
| 850 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 851 | trace_block_sleeprq(q, bio, rw_flags & 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 853 | __generic_unplug_device(q); |
| 854 | spin_unlock_irq(q->queue_lock); |
| 855 | io_schedule(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 856 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 857 | /* |
| 858 | * After sleeping, we become a "batching" process and |
| 859 | * will be able to allocate at least one request, and |
| 860 | * up to a big batch of them for a small period time. |
| 861 | * See ioc_batching, ioc_set_batching |
| 862 | */ |
| 863 | ioc = current_io_context(GFP_NOIO, q->node); |
| 864 | ioc_set_batching(q, ioc); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 865 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 866 | spin_lock_irq(q->queue_lock); |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 867 | finish_wait(&rl->wait[is_sync], &wait); |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 868 | |
| 869 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
| 870 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 871 | |
| 872 | return rq; |
| 873 | } |
| 874 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 875 | struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 876 | { |
| 877 | struct request *rq; |
| 878 | |
| 879 | BUG_ON(rw != READ && rw != WRITE); |
| 880 | |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 881 | spin_lock_irq(q->queue_lock); |
| 882 | if (gfp_mask & __GFP_WAIT) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 883 | rq = get_request_wait(q, rw, NULL); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 884 | } else { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 885 | rq = get_request(q, rw, NULL, gfp_mask); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 886 | if (!rq) |
| 887 | spin_unlock_irq(q->queue_lock); |
| 888 | } |
| 889 | /* q->queue_lock is unlocked at this point */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 890 | |
| 891 | return rq; |
| 892 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | EXPORT_SYMBOL(blk_get_request); |
| 894 | |
| 895 | /** |
| 896 | * blk_requeue_request - put a request back on queue |
| 897 | * @q: request queue where request should be inserted |
| 898 | * @rq: request to be inserted |
| 899 | * |
| 900 | * Description: |
| 901 | * Drivers often keep queueing requests until the hardware cannot accept |
| 902 | * more, when that condition happens we need to put the request back |
| 903 | * on the queue. Must be called with queue lock held. |
| 904 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 905 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | { |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 907 | blk_delete_timer(rq); |
| 908 | blk_clear_rq_complete(rq); |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 909 | trace_block_rq_requeue(q, rq); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 910 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 911 | if (blk_rq_tagged(rq)) |
| 912 | blk_queue_end_tag(q, rq); |
| 913 | |
| 914 | elv_requeue_request(q, rq); |
| 915 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | EXPORT_SYMBOL(blk_requeue_request); |
| 917 | |
| 918 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 919 | * blk_insert_request - insert a special request into a request queue |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | * @q: request queue where request should be inserted |
| 921 | * @rq: request to be inserted |
| 922 | * @at_head: insert request at head or tail of queue |
| 923 | * @data: private data |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 924 | * |
| 925 | * Description: |
| 926 | * Many block devices need to execute commands asynchronously, so they don't |
| 927 | * block the whole kernel from preemption during request execution. This is |
| 928 | * accomplished normally by inserting aritficial requests tagged as |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 929 | * REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them |
| 930 | * be scheduled for actual execution by the request queue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 931 | * |
| 932 | * We have the option of inserting the head or the tail of the queue. |
| 933 | * Typically we use the tail for new ioctls and so forth. We use the head |
| 934 | * of the queue for things like a QUEUE_FULL message from a device, or a |
| 935 | * host that is unable to accept a particular command. |
| 936 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 937 | void blk_insert_request(struct request_queue *q, struct request *rq, |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 938 | int at_head, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | { |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 940 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 941 | unsigned long flags; |
| 942 | |
| 943 | /* |
| 944 | * tell I/O scheduler that this isn't a regular read/write (ie it |
| 945 | * must not attempt merges on this) and that it acts as a soft |
| 946 | * barrier |
| 947 | */ |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 948 | rq->cmd_type = REQ_TYPE_SPECIAL; |
| 949 | rq->cmd_flags |= REQ_SOFTBARRIER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 950 | |
| 951 | rq->special = data; |
| 952 | |
| 953 | spin_lock_irqsave(q->queue_lock, flags); |
| 954 | |
| 955 | /* |
| 956 | * If command is tagged, release the tag |
| 957 | */ |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 958 | if (blk_rq_tagged(rq)) |
| 959 | blk_queue_end_tag(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 960 | |
Jerome Marchand | b238b3d | 2007-10-23 15:05:46 +0200 | [diff] [blame] | 961 | drive_stat_acct(rq, 1); |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 962 | __elv_add_request(q, rq, where, 0); |
Tejun Heo | a7f5579 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 963 | __blk_run_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 964 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 965 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | EXPORT_SYMBOL(blk_insert_request); |
| 967 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 968 | /* |
| 969 | * add-request adds a request to the linked list. |
| 970 | * queue lock is held and interrupts disabled, as we muck with the |
| 971 | * request queue list. |
| 972 | */ |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 973 | static inline void add_request(struct request_queue *q, struct request *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | { |
Jerome Marchand | b238b3d | 2007-10-23 15:05:46 +0200 | [diff] [blame] | 975 | drive_stat_acct(req, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 977 | /* |
| 978 | * elevator indicated where it wants this request to be |
| 979 | * inserted at elevator_merge time |
| 980 | */ |
| 981 | __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0); |
| 982 | } |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 983 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 984 | static void part_round_stats_single(int cpu, struct hd_struct *part, |
| 985 | unsigned long now) |
| 986 | { |
| 987 | if (now == part->stamp) |
| 988 | return; |
| 989 | |
| 990 | if (part->in_flight) { |
| 991 | __part_stat_add(cpu, part, time_in_queue, |
| 992 | part->in_flight * (now - part->stamp)); |
| 993 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
| 994 | } |
| 995 | part->stamp = now; |
| 996 | } |
| 997 | |
| 998 | /** |
Randy Dunlap | 496aa8a | 2008-10-16 07:46:23 +0200 | [diff] [blame] | 999 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
| 1000 | * @cpu: cpu number for stats access |
| 1001 | * @part: target partition |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1002 | * |
| 1003 | * The average IO queue length and utilisation statistics are maintained |
| 1004 | * by observing the current state of the queue length and the amount of |
| 1005 | * time it has been in this state for. |
| 1006 | * |
| 1007 | * Normally, that accounting is done on IO completion, but that can result |
| 1008 | * in more than a second's worth of IO being accounted for within any one |
| 1009 | * second, leading to >100% utilisation. To deal with that, we call this |
| 1010 | * function to do a round-off before returning the results when reading |
| 1011 | * /proc/diskstats. This accounts immediately for all queue usage up to |
| 1012 | * the current jiffies and restarts the counters again. |
| 1013 | */ |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1014 | void part_round_stats(int cpu, struct hd_struct *part) |
Jerome Marchand | 6f2576a | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1015 | { |
| 1016 | unsigned long now = jiffies; |
| 1017 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1018 | if (part->partno) |
| 1019 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); |
| 1020 | part_round_stats_single(cpu, part, now); |
Jerome Marchand | 6f2576a | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1021 | } |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1022 | EXPORT_SYMBOL_GPL(part_round_stats); |
Jerome Marchand | 6f2576a | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1023 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | /* |
| 1025 | * queue lock must be held |
| 1026 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1027 | void __blk_put_request(struct request_queue *q, struct request *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1029 | if (unlikely(!q)) |
| 1030 | return; |
| 1031 | if (unlikely(--req->ref_count)) |
| 1032 | return; |
| 1033 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 1034 | elv_completed_request(q, req); |
| 1035 | |
Boaz Harrosh | 1cd96c2 | 2009-03-24 12:35:07 +0100 | [diff] [blame] | 1036 | /* this is a bio leak */ |
| 1037 | WARN_ON(req->bio != NULL); |
| 1038 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | /* |
| 1040 | * Request may not have originated from ll_rw_blk. if not, |
| 1041 | * it didn't come out of our reserved rq pools |
| 1042 | */ |
Jens Axboe | 49171e5 | 2006-08-10 08:59:11 +0200 | [diff] [blame] | 1043 | if (req->cmd_flags & REQ_ALLOCED) { |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 1044 | int is_sync = rq_is_sync(req) != 0; |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1045 | int priv = req->cmd_flags & REQ_ELVPRIV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | BUG_ON(!list_empty(&req->queuelist)); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 1048 | BUG_ON(!hlist_unhashed(&req->hash)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | |
| 1050 | blk_free_request(q, req); |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 1051 | freed_request(q, is_sync, priv); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1052 | } |
| 1053 | } |
Mike Christie | 6e39b69 | 2005-11-11 05:30:24 -0600 | [diff] [blame] | 1054 | EXPORT_SYMBOL_GPL(__blk_put_request); |
| 1055 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1056 | void blk_put_request(struct request *req) |
| 1057 | { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 1058 | unsigned long flags; |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1059 | struct request_queue *q = req->q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1060 | |
FUJITA Tomonori | 52a93ba | 2008-07-15 21:21:45 +0200 | [diff] [blame] | 1061 | spin_lock_irqsave(q->queue_lock, flags); |
| 1062 | __blk_put_request(q, req); |
| 1063 | spin_unlock_irqrestore(q->queue_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1064 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | EXPORT_SYMBOL(blk_put_request); |
| 1066 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 1067 | void init_request_from_bio(struct request *req, struct bio *bio) |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1068 | { |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 1069 | req->cpu = bio->bi_comp_cpu; |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1070 | req->cmd_type = REQ_TYPE_FS; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1071 | |
| 1072 | /* |
| 1073 | * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST) |
| 1074 | */ |
Mike Christie | 6000a36 | 2008-08-19 18:45:30 -0500 | [diff] [blame] | 1075 | if (bio_rw_ahead(bio)) |
| 1076 | req->cmd_flags |= (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | |
| 1077 | REQ_FAILFAST_DRIVER); |
| 1078 | if (bio_failfast_dev(bio)) |
| 1079 | req->cmd_flags |= REQ_FAILFAST_DEV; |
| 1080 | if (bio_failfast_transport(bio)) |
| 1081 | req->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
| 1082 | if (bio_failfast_driver(bio)) |
| 1083 | req->cmd_flags |= REQ_FAILFAST_DRIVER; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1084 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1085 | if (unlikely(bio_discard(bio))) { |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1086 | req->cmd_flags |= REQ_DISCARD; |
| 1087 | if (bio_barrier(bio)) |
| 1088 | req->cmd_flags |= REQ_SOFTBARRIER; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1089 | req->q->prepare_discard_fn(req->q, req); |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1090 | } else if (unlikely(bio_barrier(bio))) |
Tejun Heo | e4025f6 | 2009-04-23 11:05:17 +0900 | [diff] [blame^] | 1091 | req->cmd_flags |= REQ_HARDBARRIER; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1092 | |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 1093 | if (bio_sync(bio)) |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1094 | req->cmd_flags |= REQ_RW_SYNC; |
Jens Axboe | 5404bc7 | 2006-08-10 09:01:02 +0200 | [diff] [blame] | 1095 | if (bio_rw_meta(bio)) |
| 1096 | req->cmd_flags |= REQ_RW_META; |
Jens Axboe | aeb6faf | 2009-04-06 14:48:07 +0200 | [diff] [blame] | 1097 | if (bio_noidle(bio)) |
| 1098 | req->cmd_flags |= REQ_NOIDLE; |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 1099 | |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1100 | req->errors = 0; |
| 1101 | req->hard_sector = req->sector = bio->bi_sector; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1102 | req->ioprio = bio_prio(bio); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1103 | req->start_time = jiffies; |
NeilBrown | bc1c56f | 2007-08-16 13:31:30 +0200 | [diff] [blame] | 1104 | blk_rq_bio_prep(req->q, req, bio); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1105 | } |
| 1106 | |
Jens Axboe | 644b2d9 | 2009-04-06 14:48:06 +0200 | [diff] [blame] | 1107 | /* |
| 1108 | * Only disabling plugging for non-rotational devices if it does tagging |
| 1109 | * as well, otherwise we do need the proper merging |
| 1110 | */ |
| 1111 | static inline bool queue_should_plug(struct request_queue *q) |
| 1112 | { |
| 1113 | return !(blk_queue_nonrot(q) && blk_queue_tagged(q)); |
| 1114 | } |
| 1115 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1116 | static int __make_request(struct request_queue *q, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1117 | { |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1118 | struct request *req; |
Tejun Heo | a738467 | 2008-11-28 13:32:03 +0900 | [diff] [blame] | 1119 | int el_ret, nr_sectors; |
Jens Axboe | 51da90f | 2006-07-18 04:14:45 +0200 | [diff] [blame] | 1120 | const unsigned short prio = bio_prio(bio); |
| 1121 | const int sync = bio_sync(bio); |
Jens Axboe | 213d941 | 2009-01-06 09:16:05 +0100 | [diff] [blame] | 1122 | const int unplug = bio_unplug(bio); |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1123 | int rw_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1124 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | nr_sectors = bio_sectors(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | |
| 1127 | /* |
| 1128 | * low level driver can indicate that it wants pages above a |
| 1129 | * certain limit bounced to low memory (ie for highmem, or even |
| 1130 | * ISA dma in theory) |
| 1131 | */ |
| 1132 | blk_queue_bounce(q, &bio); |
| 1133 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | spin_lock_irq(q->queue_lock); |
| 1135 | |
Tejun Heo | a738467 | 2008-11-28 13:32:03 +0900 | [diff] [blame] | 1136 | if (unlikely(bio_barrier(bio)) || elv_queue_empty(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1137 | goto get_rq; |
| 1138 | |
| 1139 | el_ret = elv_merge(q, &req, bio); |
| 1140 | switch (el_ret) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1141 | case ELEVATOR_BACK_MERGE: |
| 1142 | BUG_ON(!rq_mergeable(req)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1143 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1144 | if (!ll_back_merge_fn(q, req, bio)) |
| 1145 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 1147 | trace_block_bio_backmerge(q, bio); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1148 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1149 | req->biotail->bi_next = bio; |
| 1150 | req->biotail = bio; |
| 1151 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
| 1152 | req->ioprio = ioprio_best(req->ioprio, prio); |
Jens Axboe | ab780f1 | 2008-08-26 10:25:02 +0200 | [diff] [blame] | 1153 | if (!blk_rq_cpu_valid(req)) |
| 1154 | req->cpu = bio->bi_comp_cpu; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1155 | drive_stat_acct(req, 0); |
| 1156 | if (!attempt_back_merge(q, req)) |
| 1157 | elv_merged_request(q, req, el_ret); |
| 1158 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1159 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1160 | case ELEVATOR_FRONT_MERGE: |
| 1161 | BUG_ON(!rq_mergeable(req)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1163 | if (!ll_front_merge_fn(q, req, bio)) |
| 1164 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 1166 | trace_block_bio_frontmerge(q, bio); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1167 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1168 | bio->bi_next = req->bio; |
| 1169 | req->bio = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1170 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1171 | /* |
| 1172 | * may not be valid. if the low level driver said |
| 1173 | * it didn't need a bounce buffer then it better |
| 1174 | * not touch req->buffer either... |
| 1175 | */ |
| 1176 | req->buffer = bio_data(bio); |
| 1177 | req->current_nr_sectors = bio_cur_sectors(bio); |
| 1178 | req->hard_cur_sectors = req->current_nr_sectors; |
| 1179 | req->sector = req->hard_sector = bio->bi_sector; |
| 1180 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
| 1181 | req->ioprio = ioprio_best(req->ioprio, prio); |
Jens Axboe | ab780f1 | 2008-08-26 10:25:02 +0200 | [diff] [blame] | 1182 | if (!blk_rq_cpu_valid(req)) |
| 1183 | req->cpu = bio->bi_comp_cpu; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1184 | drive_stat_acct(req, 0); |
| 1185 | if (!attempt_front_merge(q, req)) |
| 1186 | elv_merged_request(q, req, el_ret); |
| 1187 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1189 | /* ELV_NO_MERGE: elevator says don't/can't merge. */ |
| 1190 | default: |
| 1191 | ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | } |
| 1193 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | get_rq: |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1195 | /* |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1196 | * This sync check and mask will be re-done in init_request_from_bio(), |
| 1197 | * but we need to set it earlier to expose the sync flag to the |
| 1198 | * rq allocator and io schedulers. |
| 1199 | */ |
| 1200 | rw_flags = bio_data_dir(bio); |
| 1201 | if (sync) |
| 1202 | rw_flags |= REQ_RW_SYNC; |
| 1203 | |
| 1204 | /* |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1205 | * Grab a free request. This is might sleep but can not fail. |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 1206 | * Returns with the queue unlocked. |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1207 | */ |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1208 | req = get_request_wait(q, rw_flags, bio); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 1209 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1210 | /* |
| 1211 | * After dropping the lock and possibly sleeping here, our request |
| 1212 | * may now be mergeable after it had proven unmergeable (above). |
| 1213 | * We don't worry about that case for efficiency. It won't happen |
| 1214 | * often, and the elevators are able to handle it. |
| 1215 | */ |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1216 | init_request_from_bio(req, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1217 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1218 | spin_lock_irq(q->queue_lock); |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 1219 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) || |
| 1220 | bio_flagged(bio, BIO_CPU_AFFINE)) |
| 1221 | req->cpu = blk_cpu_to_group(smp_processor_id()); |
Jens Axboe | 644b2d9 | 2009-04-06 14:48:06 +0200 | [diff] [blame] | 1222 | if (queue_should_plug(q) && elv_queue_empty(q)) |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1223 | blk_plug_device(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | add_request(q, req); |
| 1225 | out: |
Jens Axboe | 644b2d9 | 2009-04-06 14:48:06 +0200 | [diff] [blame] | 1226 | if (unplug || !queue_should_plug(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | __generic_unplug_device(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1228 | spin_unlock_irq(q->queue_lock); |
| 1229 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1230 | } |
| 1231 | |
| 1232 | /* |
| 1233 | * If bio->bi_dev is a partition, remap the location |
| 1234 | */ |
| 1235 | static inline void blk_partition_remap(struct bio *bio) |
| 1236 | { |
| 1237 | struct block_device *bdev = bio->bi_bdev; |
| 1238 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1239 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1240 | struct hd_struct *p = bdev->bd_part; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1241 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1242 | bio->bi_sector += p->start_sect; |
| 1243 | bio->bi_bdev = bdev->bd_contains; |
Alan D. Brunelle | c7149d6 | 2007-08-07 15:30:23 +0200 | [diff] [blame] | 1244 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 1245 | trace_block_remap(bdev_get_queue(bio->bi_bdev), bio, |
Alan D. Brunelle | c7149d6 | 2007-08-07 15:30:23 +0200 | [diff] [blame] | 1246 | bdev->bd_dev, bio->bi_sector, |
| 1247 | bio->bi_sector - p->start_sect); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1248 | } |
| 1249 | } |
| 1250 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | static void handle_bad_sector(struct bio *bio) |
| 1252 | { |
| 1253 | char b[BDEVNAME_SIZE]; |
| 1254 | |
| 1255 | printk(KERN_INFO "attempt to access beyond end of device\n"); |
| 1256 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", |
| 1257 | bdevname(bio->bi_bdev, b), |
| 1258 | bio->bi_rw, |
| 1259 | (unsigned long long)bio->bi_sector + bio_sectors(bio), |
| 1260 | (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); |
| 1261 | |
| 1262 | set_bit(BIO_EOF, &bio->bi_flags); |
| 1263 | } |
| 1264 | |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1265 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
| 1266 | |
| 1267 | static DECLARE_FAULT_ATTR(fail_make_request); |
| 1268 | |
| 1269 | static int __init setup_fail_make_request(char *str) |
| 1270 | { |
| 1271 | return setup_fault_attr(&fail_make_request, str); |
| 1272 | } |
| 1273 | __setup("fail_make_request=", setup_fail_make_request); |
| 1274 | |
| 1275 | static int should_fail_request(struct bio *bio) |
| 1276 | { |
Tejun Heo | eddb2e2 | 2008-08-25 19:56:13 +0900 | [diff] [blame] | 1277 | struct hd_struct *part = bio->bi_bdev->bd_part; |
| 1278 | |
| 1279 | if (part_to_disk(part)->part0.make_it_fail || part->make_it_fail) |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1280 | return should_fail(&fail_make_request, bio->bi_size); |
| 1281 | |
| 1282 | return 0; |
| 1283 | } |
| 1284 | |
| 1285 | static int __init fail_make_request_debugfs(void) |
| 1286 | { |
| 1287 | return init_fault_attr_dentries(&fail_make_request, |
| 1288 | "fail_make_request"); |
| 1289 | } |
| 1290 | |
| 1291 | late_initcall(fail_make_request_debugfs); |
| 1292 | |
| 1293 | #else /* CONFIG_FAIL_MAKE_REQUEST */ |
| 1294 | |
| 1295 | static inline int should_fail_request(struct bio *bio) |
| 1296 | { |
| 1297 | return 0; |
| 1298 | } |
| 1299 | |
| 1300 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ |
| 1301 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1302 | /* |
| 1303 | * Check whether this bio extends beyond the end of the device. |
| 1304 | */ |
| 1305 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) |
| 1306 | { |
| 1307 | sector_t maxsector; |
| 1308 | |
| 1309 | if (!nr_sectors) |
| 1310 | return 0; |
| 1311 | |
| 1312 | /* Test device or partition size, when known. */ |
| 1313 | maxsector = bio->bi_bdev->bd_inode->i_size >> 9; |
| 1314 | if (maxsector) { |
| 1315 | sector_t sector = bio->bi_sector; |
| 1316 | |
| 1317 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { |
| 1318 | /* |
| 1319 | * This may well happen - the kernel calls bread() |
| 1320 | * without checking the size of the device, e.g., when |
| 1321 | * mounting a device. |
| 1322 | */ |
| 1323 | handle_bad_sector(bio); |
| 1324 | return 1; |
| 1325 | } |
| 1326 | } |
| 1327 | |
| 1328 | return 0; |
| 1329 | } |
| 1330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1332 | * generic_make_request - hand a buffer to its device driver for I/O |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1333 | * @bio: The bio describing the location in memory and on the device. |
| 1334 | * |
| 1335 | * generic_make_request() is used to make I/O requests of block |
| 1336 | * devices. It is passed a &struct bio, which describes the I/O that needs |
| 1337 | * to be done. |
| 1338 | * |
| 1339 | * generic_make_request() does not return any status. The |
| 1340 | * success/failure status of the request, along with notification of |
| 1341 | * completion, is delivered asynchronously through the bio->bi_end_io |
| 1342 | * function described (one day) else where. |
| 1343 | * |
| 1344 | * The caller of generic_make_request must make sure that bi_io_vec |
| 1345 | * are set to describe the memory buffer, and that bi_dev and bi_sector are |
| 1346 | * set to describe the device address, and the |
| 1347 | * bi_end_io and optionally bi_private are set to describe how |
| 1348 | * completion notification should be signaled. |
| 1349 | * |
| 1350 | * generic_make_request and the drivers it calls may use bi_next if this |
| 1351 | * bio happens to be merged with someone else, and may change bi_dev and |
| 1352 | * bi_sector for remaps as it sees fit. So the values of these fields |
| 1353 | * should NOT be depended on after the call to generic_make_request. |
| 1354 | */ |
Neil Brown | d89d879 | 2007-05-01 09:53:42 +0200 | [diff] [blame] | 1355 | static inline void __generic_make_request(struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1356 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1357 | struct request_queue *q; |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1358 | sector_t old_sector; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1359 | int ret, nr_sectors = bio_sectors(bio); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1360 | dev_t old_dev; |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1361 | int err = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1362 | |
| 1363 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1364 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1365 | if (bio_check_eod(bio, nr_sectors)) |
| 1366 | goto end_io; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1367 | |
| 1368 | /* |
| 1369 | * Resolve the mapping until finished. (drivers are |
| 1370 | * still free to implement/resolve their own stacking |
| 1371 | * by explicitly returning 0) |
| 1372 | * |
| 1373 | * NOTE: we don't repeat the blk_size check for each new device. |
| 1374 | * Stacking drivers are expected to know what they are doing. |
| 1375 | */ |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1376 | old_sector = -1; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1377 | old_dev = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | do { |
| 1379 | char b[BDEVNAME_SIZE]; |
| 1380 | |
| 1381 | q = bdev_get_queue(bio->bi_bdev); |
Tejun Heo | a738467 | 2008-11-28 13:32:03 +0900 | [diff] [blame] | 1382 | if (unlikely(!q)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | printk(KERN_ERR |
| 1384 | "generic_make_request: Trying to access " |
| 1385 | "nonexistent block-device %s (%Lu)\n", |
| 1386 | bdevname(bio->bi_bdev, b), |
| 1387 | (long long) bio->bi_sector); |
Tejun Heo | a738467 | 2008-11-28 13:32:03 +0900 | [diff] [blame] | 1388 | goto end_io; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1389 | } |
| 1390 | |
Jens Axboe | 4fa253f | 2007-07-18 13:13:10 +0200 | [diff] [blame] | 1391 | if (unlikely(nr_sectors > q->max_hw_sectors)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1392 | printk(KERN_ERR "bio too big device %s (%u > %u)\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1393 | bdevname(bio->bi_bdev, b), |
| 1394 | bio_sectors(bio), |
| 1395 | q->max_hw_sectors); |
| 1396 | goto end_io; |
| 1397 | } |
| 1398 | |
Nick Piggin | fde6ad2 | 2005-06-23 00:08:53 -0700 | [diff] [blame] | 1399 | if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1400 | goto end_io; |
| 1401 | |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1402 | if (should_fail_request(bio)) |
| 1403 | goto end_io; |
| 1404 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1405 | /* |
| 1406 | * If this device has partitions, remap block n |
| 1407 | * of partition p to block n+start(p) of the disk. |
| 1408 | */ |
| 1409 | blk_partition_remap(bio); |
| 1410 | |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 1411 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) |
| 1412 | goto end_io; |
| 1413 | |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1414 | if (old_sector != -1) |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 1415 | trace_block_remap(q, bio, old_dev, bio->bi_sector, |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1416 | old_sector); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1417 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 1418 | trace_block_bio_queue(q, bio); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1419 | |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1420 | old_sector = bio->bi_sector; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1421 | old_dev = bio->bi_bdev->bd_dev; |
| 1422 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1423 | if (bio_check_eod(bio, nr_sectors)) |
| 1424 | goto end_io; |
Tejun Heo | a738467 | 2008-11-28 13:32:03 +0900 | [diff] [blame] | 1425 | |
| 1426 | if (bio_discard(bio) && !q->prepare_discard_fn) { |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1427 | err = -EOPNOTSUPP; |
| 1428 | goto end_io; |
| 1429 | } |
Jens Axboe | cec0707 | 2009-01-13 15:28:32 +0100 | [diff] [blame] | 1430 | if (bio_barrier(bio) && bio_has_data(bio) && |
| 1431 | (q->next_ordered == QUEUE_ORDERED_NONE)) { |
| 1432 | err = -EOPNOTSUPP; |
| 1433 | goto end_io; |
| 1434 | } |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1435 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1436 | ret = q->make_request_fn(q, bio); |
| 1437 | } while (ret); |
Tejun Heo | a738467 | 2008-11-28 13:32:03 +0900 | [diff] [blame] | 1438 | |
| 1439 | return; |
| 1440 | |
| 1441 | end_io: |
| 1442 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | } |
| 1444 | |
Neil Brown | d89d879 | 2007-05-01 09:53:42 +0200 | [diff] [blame] | 1445 | /* |
| 1446 | * We only want one ->make_request_fn to be active at a time, |
| 1447 | * else stack usage with stacked devices could be a problem. |
| 1448 | * So use current->bio_{list,tail} to keep a list of requests |
| 1449 | * submited by a make_request_fn function. |
| 1450 | * current->bio_tail is also used as a flag to say if |
| 1451 | * generic_make_request is currently active in this task or not. |
| 1452 | * If it is NULL, then no make_request is active. If it is non-NULL, |
| 1453 | * then a make_request is active, and new requests should be added |
| 1454 | * at the tail |
| 1455 | */ |
| 1456 | void generic_make_request(struct bio *bio) |
| 1457 | { |
| 1458 | if (current->bio_tail) { |
| 1459 | /* make_request is active */ |
| 1460 | *(current->bio_tail) = bio; |
| 1461 | bio->bi_next = NULL; |
| 1462 | current->bio_tail = &bio->bi_next; |
| 1463 | return; |
| 1464 | } |
| 1465 | /* following loop may be a bit non-obvious, and so deserves some |
| 1466 | * explanation. |
| 1467 | * Before entering the loop, bio->bi_next is NULL (as all callers |
| 1468 | * ensure that) so we have a list with a single bio. |
| 1469 | * We pretend that we have just taken it off a longer list, so |
| 1470 | * we assign bio_list to the next (which is NULL) and bio_tail |
| 1471 | * to &bio_list, thus initialising the bio_list of new bios to be |
| 1472 | * added. __generic_make_request may indeed add some more bios |
| 1473 | * through a recursive call to generic_make_request. If it |
| 1474 | * did, we find a non-NULL value in bio_list and re-enter the loop |
| 1475 | * from the top. In this case we really did just take the bio |
| 1476 | * of the top of the list (no pretending) and so fixup bio_list and |
| 1477 | * bio_tail or bi_next, and call into __generic_make_request again. |
| 1478 | * |
| 1479 | * The loop was structured like this to make only one call to |
| 1480 | * __generic_make_request (which is important as it is large and |
| 1481 | * inlined) and to keep the structure simple. |
| 1482 | */ |
| 1483 | BUG_ON(bio->bi_next); |
| 1484 | do { |
| 1485 | current->bio_list = bio->bi_next; |
| 1486 | if (bio->bi_next == NULL) |
| 1487 | current->bio_tail = ¤t->bio_list; |
| 1488 | else |
| 1489 | bio->bi_next = NULL; |
| 1490 | __generic_make_request(bio); |
| 1491 | bio = current->bio_list; |
| 1492 | } while (bio); |
| 1493 | current->bio_tail = NULL; /* deactivate */ |
| 1494 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1495 | EXPORT_SYMBOL(generic_make_request); |
| 1496 | |
| 1497 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1498 | * submit_bio - submit a bio to the block device layer for I/O |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1499 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
| 1500 | * @bio: The &struct bio which describes the I/O |
| 1501 | * |
| 1502 | * submit_bio() is very similar in purpose to generic_make_request(), and |
| 1503 | * uses that function to do most of the work. Both are fairly rough |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1504 | * interfaces; @bio must be presetup and ready for I/O. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1505 | * |
| 1506 | */ |
| 1507 | void submit_bio(int rw, struct bio *bio) |
| 1508 | { |
| 1509 | int count = bio_sectors(bio); |
| 1510 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1511 | bio->bi_rw |= rw; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1512 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1513 | /* |
| 1514 | * If it's a regular read/write or a barrier with data attached, |
| 1515 | * go through the normal accounting stuff before submission. |
| 1516 | */ |
Jens Axboe | a9c701e | 2008-08-08 11:04:44 +0200 | [diff] [blame] | 1517 | if (bio_has_data(bio)) { |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1518 | if (rw & WRITE) { |
| 1519 | count_vm_events(PGPGOUT, count); |
| 1520 | } else { |
| 1521 | task_io_account_read(bio->bi_size); |
| 1522 | count_vm_events(PGPGIN, count); |
| 1523 | } |
| 1524 | |
| 1525 | if (unlikely(block_dump)) { |
| 1526 | char b[BDEVNAME_SIZE]; |
| 1527 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1528 | current->comm, task_pid_nr(current), |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1529 | (rw & WRITE) ? "WRITE" : "READ", |
| 1530 | (unsigned long long)bio->bi_sector, |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1531 | bdevname(bio->bi_bdev, b)); |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1532 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1533 | } |
| 1534 | |
| 1535 | generic_make_request(bio); |
| 1536 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1537 | EXPORT_SYMBOL(submit_bio); |
| 1538 | |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1539 | /** |
Kiyoshi Ueda | 82124d6 | 2008-09-18 10:45:38 -0400 | [diff] [blame] | 1540 | * blk_rq_check_limits - Helper function to check a request for the queue limit |
| 1541 | * @q: the queue |
| 1542 | * @rq: the request being checked |
| 1543 | * |
| 1544 | * Description: |
| 1545 | * @rq may have been made based on weaker limitations of upper-level queues |
| 1546 | * in request stacking drivers, and it may violate the limitation of @q. |
| 1547 | * Since the block layer and the underlying device driver trust @rq |
| 1548 | * after it is inserted to @q, it should be checked against @q before |
| 1549 | * the insertion using this generic function. |
| 1550 | * |
| 1551 | * This function should also be useful for request stacking drivers |
| 1552 | * in some cases below, so export this fuction. |
| 1553 | * Request stacking drivers like request-based dm may change the queue |
| 1554 | * limits while requests are in the queue (e.g. dm's table swapping). |
| 1555 | * Such request stacking drivers should check those requests agaist |
| 1556 | * the new queue limits again when they dispatch those requests, |
| 1557 | * although such checkings are also done against the old queue limits |
| 1558 | * when submitting requests. |
| 1559 | */ |
| 1560 | int blk_rq_check_limits(struct request_queue *q, struct request *rq) |
| 1561 | { |
| 1562 | if (rq->nr_sectors > q->max_sectors || |
| 1563 | rq->data_len > q->max_hw_sectors << 9) { |
| 1564 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
| 1565 | return -EIO; |
| 1566 | } |
| 1567 | |
| 1568 | /* |
| 1569 | * queue's settings related to segment counting like q->bounce_pfn |
| 1570 | * may differ from that of other stacking queues. |
| 1571 | * Recalculate it to check the request correctly on this queue's |
| 1572 | * limitation. |
| 1573 | */ |
| 1574 | blk_recalc_rq_segments(rq); |
| 1575 | if (rq->nr_phys_segments > q->max_phys_segments || |
| 1576 | rq->nr_phys_segments > q->max_hw_segments) { |
| 1577 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
| 1578 | return -EIO; |
| 1579 | } |
| 1580 | |
| 1581 | return 0; |
| 1582 | } |
| 1583 | EXPORT_SYMBOL_GPL(blk_rq_check_limits); |
| 1584 | |
| 1585 | /** |
| 1586 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request |
| 1587 | * @q: the queue to submit the request |
| 1588 | * @rq: the request being queued |
| 1589 | */ |
| 1590 | int blk_insert_cloned_request(struct request_queue *q, struct request *rq) |
| 1591 | { |
| 1592 | unsigned long flags; |
| 1593 | |
| 1594 | if (blk_rq_check_limits(q, rq)) |
| 1595 | return -EIO; |
| 1596 | |
| 1597 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
| 1598 | if (rq->rq_disk && rq->rq_disk->part0.make_it_fail && |
| 1599 | should_fail(&fail_make_request, blk_rq_bytes(rq))) |
| 1600 | return -EIO; |
| 1601 | #endif |
| 1602 | |
| 1603 | spin_lock_irqsave(q->queue_lock, flags); |
| 1604 | |
| 1605 | /* |
| 1606 | * Submitting request must be dequeued before calling this function |
| 1607 | * because it will be linked to another request_queue |
| 1608 | */ |
| 1609 | BUG_ON(blk_queued_rq(rq)); |
| 1610 | |
| 1611 | drive_stat_acct(rq, 1); |
| 1612 | __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); |
| 1613 | |
| 1614 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1615 | |
| 1616 | return 0; |
| 1617 | } |
| 1618 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); |
| 1619 | |
| 1620 | /** |
Tejun Heo | 53a0880 | 2008-12-03 12:41:26 +0100 | [diff] [blame] | 1621 | * blkdev_dequeue_request - dequeue request and start timeout timer |
| 1622 | * @req: request to dequeue |
| 1623 | * |
| 1624 | * Dequeue @req and start timeout timer on it. This hands off the |
| 1625 | * request to the driver. |
| 1626 | * |
| 1627 | * Block internal functions which don't want to start timer should |
| 1628 | * call elv_dequeue_request(). |
| 1629 | */ |
| 1630 | void blkdev_dequeue_request(struct request *req) |
| 1631 | { |
| 1632 | elv_dequeue_request(req->q, req); |
| 1633 | |
| 1634 | /* |
| 1635 | * We are now handing the request to the hardware, add the |
| 1636 | * timeout handler. |
| 1637 | */ |
| 1638 | blk_add_timer(req); |
| 1639 | } |
| 1640 | EXPORT_SYMBOL(blkdev_dequeue_request); |
| 1641 | |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 1642 | static void blk_account_io_completion(struct request *req, unsigned int bytes) |
| 1643 | { |
Jerome Marchand | 26308ea | 2009-03-27 10:31:51 +0100 | [diff] [blame] | 1644 | if (!blk_do_io_stat(req)) |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 1645 | return; |
| 1646 | |
| 1647 | if (blk_fs_request(req)) { |
| 1648 | const int rw = rq_data_dir(req); |
| 1649 | struct hd_struct *part; |
| 1650 | int cpu; |
| 1651 | |
| 1652 | cpu = part_stat_lock(); |
| 1653 | part = disk_map_sector_rcu(req->rq_disk, req->sector); |
| 1654 | part_stat_add(cpu, part, sectors[rw], bytes >> 9); |
| 1655 | part_stat_unlock(); |
| 1656 | } |
| 1657 | } |
| 1658 | |
| 1659 | static void blk_account_io_done(struct request *req) |
| 1660 | { |
Jerome Marchand | 26308ea | 2009-03-27 10:31:51 +0100 | [diff] [blame] | 1661 | if (!blk_do_io_stat(req)) |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 1662 | return; |
| 1663 | |
| 1664 | /* |
| 1665 | * Account IO completion. bar_rq isn't accounted as a normal |
| 1666 | * IO on queueing nor completion. Accounting the containing |
| 1667 | * request is enough. |
| 1668 | */ |
| 1669 | if (blk_fs_request(req) && req != &req->q->bar_rq) { |
| 1670 | unsigned long duration = jiffies - req->start_time; |
| 1671 | const int rw = rq_data_dir(req); |
| 1672 | struct hd_struct *part; |
| 1673 | int cpu; |
| 1674 | |
| 1675 | cpu = part_stat_lock(); |
Jerome Marchand | 26308ea | 2009-03-27 10:31:51 +0100 | [diff] [blame] | 1676 | part = disk_map_sector_rcu(req->rq_disk, req->sector); |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 1677 | |
| 1678 | part_stat_inc(cpu, part, ios[rw]); |
| 1679 | part_stat_add(cpu, part, ticks[rw], duration); |
| 1680 | part_round_stats(cpu, part); |
| 1681 | part_dec_in_flight(part); |
| 1682 | |
| 1683 | part_stat_unlock(); |
| 1684 | } |
| 1685 | } |
| 1686 | |
Tejun Heo | 53a0880 | 2008-12-03 12:41:26 +0100 | [diff] [blame] | 1687 | /** |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1688 | * __end_that_request_first - end I/O on a request |
| 1689 | * @req: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1690 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1691 | * @nr_bytes: number of bytes to complete |
| 1692 | * |
| 1693 | * Description: |
| 1694 | * Ends I/O on a number of bytes attached to @req, and sets it up |
| 1695 | * for the next range of segments (if any) in the cluster. |
| 1696 | * |
| 1697 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1698 | * %0 - we are done with this request, call end_that_request_last() |
| 1699 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1700 | **/ |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1701 | static int __end_that_request_first(struct request *req, int error, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1702 | int nr_bytes) |
| 1703 | { |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1704 | int total_bytes, bio_nbytes, next_idx = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1705 | struct bio *bio; |
| 1706 | |
Arnaldo Carvalho de Melo | 5f3ea37 | 2008-10-30 08:34:33 +0100 | [diff] [blame] | 1707 | trace_block_rq_complete(req->q, req); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1708 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1709 | /* |
Tejun Heo | 924cec7 | 2009-04-19 07:00:41 +0900 | [diff] [blame] | 1710 | * For fs requests, rq is just carrier of independent bio's |
| 1711 | * and each partial completion should be handled separately. |
| 1712 | * Reset per-request error on each partial completion. |
| 1713 | * |
| 1714 | * TODO: tj: This is too subtle. It would be better to let |
| 1715 | * low level drivers do what they see fit. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1716 | */ |
Tejun Heo | 924cec7 | 2009-04-19 07:00:41 +0900 | [diff] [blame] | 1717 | if (blk_fs_request(req)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1718 | req->errors = 0; |
| 1719 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1720 | if (error && (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))) { |
| 1721 | printk(KERN_ERR "end_request: I/O error, dev %s, sector %llu\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1722 | req->rq_disk ? req->rq_disk->disk_name : "?", |
| 1723 | (unsigned long long)req->sector); |
| 1724 | } |
| 1725 | |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 1726 | blk_account_io_completion(req, nr_bytes); |
Jens Axboe | d72d904 | 2005-11-01 08:35:42 +0100 | [diff] [blame] | 1727 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1728 | total_bytes = bio_nbytes = 0; |
| 1729 | while ((bio = req->bio) != NULL) { |
| 1730 | int nbytes; |
| 1731 | |
| 1732 | if (nr_bytes >= bio->bi_size) { |
| 1733 | req->bio = bio->bi_next; |
| 1734 | nbytes = bio->bi_size; |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 1735 | req_bio_endio(req, bio, nbytes, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1736 | next_idx = 0; |
| 1737 | bio_nbytes = 0; |
| 1738 | } else { |
| 1739 | int idx = bio->bi_idx + next_idx; |
| 1740 | |
| 1741 | if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { |
| 1742 | blk_dump_rq_flags(req, "__end_that"); |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1743 | printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n", |
Harvey Harrison | 24c03d4 | 2008-05-01 04:35:17 -0700 | [diff] [blame] | 1744 | __func__, bio->bi_idx, bio->bi_vcnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1745 | break; |
| 1746 | } |
| 1747 | |
| 1748 | nbytes = bio_iovec_idx(bio, idx)->bv_len; |
| 1749 | BIO_BUG_ON(nbytes > bio->bi_size); |
| 1750 | |
| 1751 | /* |
| 1752 | * not a complete bvec done |
| 1753 | */ |
| 1754 | if (unlikely(nbytes > nr_bytes)) { |
| 1755 | bio_nbytes += nr_bytes; |
| 1756 | total_bytes += nr_bytes; |
| 1757 | break; |
| 1758 | } |
| 1759 | |
| 1760 | /* |
| 1761 | * advance to the next vector |
| 1762 | */ |
| 1763 | next_idx++; |
| 1764 | bio_nbytes += nbytes; |
| 1765 | } |
| 1766 | |
| 1767 | total_bytes += nbytes; |
| 1768 | nr_bytes -= nbytes; |
| 1769 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1770 | bio = req->bio; |
| 1771 | if (bio) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1772 | /* |
| 1773 | * end more in this run, or just return 'not-done' |
| 1774 | */ |
| 1775 | if (unlikely(nr_bytes <= 0)) |
| 1776 | break; |
| 1777 | } |
| 1778 | } |
| 1779 | |
| 1780 | /* |
| 1781 | * completely done |
| 1782 | */ |
| 1783 | if (!req->bio) |
| 1784 | return 0; |
| 1785 | |
| 1786 | /* |
| 1787 | * if the request wasn't completed, update state |
| 1788 | */ |
| 1789 | if (bio_nbytes) { |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 1790 | req_bio_endio(req, bio, bio_nbytes, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1791 | bio->bi_idx += next_idx; |
| 1792 | bio_iovec(bio)->bv_offset += nr_bytes; |
| 1793 | bio_iovec(bio)->bv_len -= nr_bytes; |
| 1794 | } |
| 1795 | |
| 1796 | blk_recalc_rq_sectors(req, total_bytes >> 9); |
| 1797 | blk_recalc_rq_segments(req); |
| 1798 | return 1; |
| 1799 | } |
| 1800 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1801 | /* |
| 1802 | * queue lock must be held |
| 1803 | */ |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1804 | static void end_that_request_last(struct request *req, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1805 | { |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1806 | if (blk_rq_tagged(req)) |
| 1807 | blk_queue_end_tag(req->q, req); |
| 1808 | |
| 1809 | if (blk_queued_rq(req)) |
Tejun Heo | 53a0880 | 2008-12-03 12:41:26 +0100 | [diff] [blame] | 1810 | elv_dequeue_request(req->q, req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1811 | |
| 1812 | if (unlikely(laptop_mode) && blk_fs_request(req)) |
| 1813 | laptop_io_completion(); |
| 1814 | |
Mike Anderson | e78042e | 2008-10-30 02:16:20 -0700 | [diff] [blame] | 1815 | blk_delete_timer(req); |
| 1816 | |
Jens Axboe | bc58ba9 | 2009-01-23 10:54:44 +0100 | [diff] [blame] | 1817 | blk_account_io_done(req); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1818 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1819 | if (req->end_io) |
Tejun Heo | 8ffdc65 | 2006-01-06 09:49:03 +0100 | [diff] [blame] | 1820 | req->end_io(req, error); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1821 | else { |
| 1822 | if (blk_bidi_rq(req)) |
| 1823 | __blk_put_request(req->next_rq->q, req->next_rq); |
| 1824 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1825 | __blk_put_request(req->q, req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1826 | } |
| 1827 | } |
| 1828 | |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1829 | /** |
| 1830 | * blk_rq_bytes - Returns bytes left to complete in the entire request |
Randy Dunlap | 5d87a05 | 2008-02-20 09:01:22 +0100 | [diff] [blame] | 1831 | * @rq: the request being processed |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1832 | **/ |
| 1833 | unsigned int blk_rq_bytes(struct request *rq) |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1834 | { |
| 1835 | if (blk_fs_request(rq)) |
| 1836 | return rq->hard_nr_sectors << 9; |
| 1837 | |
| 1838 | return rq->data_len; |
| 1839 | } |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1840 | EXPORT_SYMBOL_GPL(blk_rq_bytes); |
| 1841 | |
| 1842 | /** |
| 1843 | * blk_rq_cur_bytes - Returns bytes left to complete in the current segment |
Randy Dunlap | 5d87a05 | 2008-02-20 09:01:22 +0100 | [diff] [blame] | 1844 | * @rq: the request being processed |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1845 | **/ |
| 1846 | unsigned int blk_rq_cur_bytes(struct request *rq) |
| 1847 | { |
| 1848 | if (blk_fs_request(rq)) |
| 1849 | return rq->current_nr_sectors << 9; |
| 1850 | |
| 1851 | if (rq->bio) |
| 1852 | return rq->bio->bi_size; |
| 1853 | |
| 1854 | return rq->data_len; |
| 1855 | } |
| 1856 | EXPORT_SYMBOL_GPL(blk_rq_cur_bytes); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1857 | |
| 1858 | /** |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1859 | * end_request - end I/O on the current segment of the request |
Randy Dunlap | 8f731f7 | 2007-10-18 23:39:28 -0700 | [diff] [blame] | 1860 | * @req: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1861 | * @uptodate: error value or %0/%1 uptodate flag |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1862 | * |
| 1863 | * Description: |
| 1864 | * Ends I/O on the current segment of a request. If that is the only |
| 1865 | * remaining segment, the request is also completed and freed. |
| 1866 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1867 | * This is a remnant of how older block drivers handled I/O completions. |
| 1868 | * Modern drivers typically end I/O on the full request in one go, unless |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1869 | * they have a residual value to account for. For that case this function |
| 1870 | * isn't really useful, unless the residual just happens to be the |
| 1871 | * full current segment. In other words, don't use this function in new |
Kiyoshi Ueda | d00e29f | 2008-10-01 10:14:46 -0400 | [diff] [blame] | 1872 | * code. Use blk_end_request() or __blk_end_request() to end a request. |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1873 | **/ |
| 1874 | void end_request(struct request *req, int uptodate) |
| 1875 | { |
Kiyoshi Ueda | d00e29f | 2008-10-01 10:14:46 -0400 | [diff] [blame] | 1876 | int error = 0; |
| 1877 | |
| 1878 | if (uptodate <= 0) |
| 1879 | error = uptodate ? uptodate : -EIO; |
| 1880 | |
| 1881 | __blk_end_request(req, error, req->hard_cur_sectors << 9); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1882 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1883 | EXPORT_SYMBOL(end_request); |
| 1884 | |
Kiyoshi Ueda | 32fab44 | 2008-09-18 10:45:09 -0400 | [diff] [blame] | 1885 | static int end_that_request_data(struct request *rq, int error, |
| 1886 | unsigned int nr_bytes, unsigned int bidi_bytes) |
| 1887 | { |
| 1888 | if (rq->bio) { |
| 1889 | if (__end_that_request_first(rq, error, nr_bytes)) |
| 1890 | return 1; |
| 1891 | |
| 1892 | /* Bidi request must be completed as a whole */ |
| 1893 | if (blk_bidi_rq(rq) && |
| 1894 | __end_that_request_first(rq->next_rq, error, bidi_bytes)) |
| 1895 | return 1; |
| 1896 | } |
| 1897 | |
| 1898 | return 0; |
| 1899 | } |
| 1900 | |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1901 | /** |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1902 | * blk_end_io - Generic end_io function to complete a request. |
| 1903 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1904 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1905 | * @nr_bytes: number of bytes to complete @rq |
| 1906 | * @bidi_bytes: number of bytes to complete @rq->next_rq |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1907 | * @drv_callback: function called between completion of bios in the request |
| 1908 | * and completion of the request. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1909 | * If the callback returns non %0, this helper returns without |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1910 | * completion of the request. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1911 | * |
| 1912 | * Description: |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1913 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1914 | * If @rq has leftover, sets it up for the next range of segments. |
| 1915 | * |
| 1916 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1917 | * %0 - we are done with this request |
| 1918 | * %1 - this request is not freed yet, it still has pending buffers. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1919 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1920 | static int blk_end_io(struct request *rq, int error, unsigned int nr_bytes, |
| 1921 | unsigned int bidi_bytes, |
| 1922 | int (drv_callback)(struct request *)) |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1923 | { |
| 1924 | struct request_queue *q = rq->q; |
| 1925 | unsigned long flags = 0UL; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1926 | |
Kiyoshi Ueda | 32fab44 | 2008-09-18 10:45:09 -0400 | [diff] [blame] | 1927 | if (end_that_request_data(rq, error, nr_bytes, bidi_bytes)) |
| 1928 | return 1; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1929 | |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1930 | /* Special feature for tricky drivers */ |
| 1931 | if (drv_callback && drv_callback(rq)) |
| 1932 | return 1; |
| 1933 | |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1934 | add_disk_randomness(rq->rq_disk); |
| 1935 | |
| 1936 | spin_lock_irqsave(q->queue_lock, flags); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1937 | end_that_request_last(rq, error); |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1938 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1939 | |
| 1940 | return 0; |
| 1941 | } |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1942 | |
| 1943 | /** |
| 1944 | * blk_end_request - Helper function for drivers to complete the request. |
| 1945 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1946 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1947 | * @nr_bytes: number of bytes to complete |
| 1948 | * |
| 1949 | * Description: |
| 1950 | * Ends I/O on a number of bytes attached to @rq. |
| 1951 | * If @rq has leftover, sets it up for the next range of segments. |
| 1952 | * |
| 1953 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1954 | * %0 - we are done with this request |
| 1955 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1956 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1957 | int blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1958 | { |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1959 | return blk_end_io(rq, error, nr_bytes, 0, NULL); |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1960 | } |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1961 | EXPORT_SYMBOL_GPL(blk_end_request); |
| 1962 | |
| 1963 | /** |
| 1964 | * __blk_end_request - Helper function for drivers to complete the request. |
| 1965 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1966 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1967 | * @nr_bytes: number of bytes to complete |
| 1968 | * |
| 1969 | * Description: |
| 1970 | * Must be called with queue lock held unlike blk_end_request(). |
| 1971 | * |
| 1972 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1973 | * %0 - we are done with this request |
| 1974 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1975 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1976 | int __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1977 | { |
Jens Axboe | 6054016 | 2008-08-26 13:34:34 +0200 | [diff] [blame] | 1978 | if (rq->bio && __end_that_request_first(rq, error, nr_bytes)) |
Jens Axboe | 051cc39 | 2008-08-08 11:06:45 +0200 | [diff] [blame] | 1979 | return 1; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1980 | |
| 1981 | add_disk_randomness(rq->rq_disk); |
| 1982 | |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1983 | end_that_request_last(rq, error); |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1984 | |
| 1985 | return 0; |
| 1986 | } |
| 1987 | EXPORT_SYMBOL_GPL(__blk_end_request); |
| 1988 | |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1989 | /** |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1990 | * blk_end_bidi_request - Helper function for drivers to complete bidi request. |
| 1991 | * @rq: the bidi request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1992 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1993 | * @nr_bytes: number of bytes to complete @rq |
| 1994 | * @bidi_bytes: number of bytes to complete @rq->next_rq |
| 1995 | * |
| 1996 | * Description: |
| 1997 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
| 1998 | * |
| 1999 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2000 | * %0 - we are done with this request |
| 2001 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 2002 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 2003 | int blk_end_bidi_request(struct request *rq, int error, unsigned int nr_bytes, |
| 2004 | unsigned int bidi_bytes) |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 2005 | { |
| 2006 | return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL); |
| 2007 | } |
| 2008 | EXPORT_SYMBOL_GPL(blk_end_bidi_request); |
| 2009 | |
| 2010 | /** |
Kiyoshi Ueda | 32fab44 | 2008-09-18 10:45:09 -0400 | [diff] [blame] | 2011 | * blk_update_request - Special helper function for request stacking drivers |
| 2012 | * @rq: the request being processed |
| 2013 | * @error: %0 for success, < %0 for error |
| 2014 | * @nr_bytes: number of bytes to complete @rq |
| 2015 | * |
| 2016 | * Description: |
| 2017 | * Ends I/O on a number of bytes attached to @rq, but doesn't complete |
| 2018 | * the request structure even if @rq doesn't have leftover. |
| 2019 | * If @rq has leftover, sets it up for the next range of segments. |
| 2020 | * |
| 2021 | * This special helper function is only for request stacking drivers |
| 2022 | * (e.g. request-based dm) so that they can handle partial completion. |
| 2023 | * Actual device drivers should use blk_end_request instead. |
| 2024 | */ |
| 2025 | void blk_update_request(struct request *rq, int error, unsigned int nr_bytes) |
| 2026 | { |
| 2027 | if (!end_that_request_data(rq, error, nr_bytes, 0)) { |
| 2028 | /* |
| 2029 | * These members are not updated in end_that_request_data() |
| 2030 | * when all bios are completed. |
| 2031 | * Update them so that the request stacking driver can find |
| 2032 | * how many bytes remain in the request later. |
| 2033 | */ |
| 2034 | rq->nr_sectors = rq->hard_nr_sectors = 0; |
| 2035 | rq->current_nr_sectors = rq->hard_cur_sectors = 0; |
| 2036 | } |
| 2037 | } |
| 2038 | EXPORT_SYMBOL_GPL(blk_update_request); |
| 2039 | |
| 2040 | /** |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2041 | * blk_end_request_callback - Special helper function for tricky drivers |
| 2042 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2043 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2044 | * @nr_bytes: number of bytes to complete |
| 2045 | * @drv_callback: function called between completion of bios in the request |
| 2046 | * and completion of the request. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2047 | * If the callback returns non %0, this helper returns without |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2048 | * completion of the request. |
| 2049 | * |
| 2050 | * Description: |
| 2051 | * Ends I/O on a number of bytes attached to @rq. |
| 2052 | * If @rq has leftover, sets it up for the next range of segments. |
| 2053 | * |
| 2054 | * This special helper function is used only for existing tricky drivers. |
| 2055 | * (e.g. cdrom_newpc_intr() of ide-cd) |
| 2056 | * This interface will be removed when such drivers are rewritten. |
| 2057 | * Don't use this interface in other places anymore. |
| 2058 | * |
| 2059 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2060 | * %0 - we are done with this request |
| 2061 | * %1 - this request is not freed yet. |
| 2062 | * this request still has pending buffers or |
| 2063 | * the driver doesn't want to finish this request yet. |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2064 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 2065 | int blk_end_request_callback(struct request *rq, int error, |
| 2066 | unsigned int nr_bytes, |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2067 | int (drv_callback)(struct request *)) |
| 2068 | { |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 2069 | return blk_end_io(rq, error, nr_bytes, 0, drv_callback); |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2070 | } |
| 2071 | EXPORT_SYMBOL_GPL(blk_end_request_callback); |
| 2072 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 2073 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
| 2074 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2075 | { |
David Woodhouse | d628eae | 2008-08-09 16:22:17 +0100 | [diff] [blame] | 2076 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw, and |
| 2077 | we want BIO_RW_AHEAD (bit 1) to imply REQ_FAILFAST (bit 1). */ |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 2078 | rq->cmd_flags |= (bio->bi_rw & 3); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2079 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 2080 | if (bio_has_data(bio)) { |
| 2081 | rq->nr_phys_segments = bio_phys_segments(q, bio); |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 2082 | rq->buffer = bio_data(bio); |
| 2083 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2084 | rq->current_nr_sectors = bio_cur_sectors(bio); |
| 2085 | rq->hard_cur_sectors = rq->current_nr_sectors; |
| 2086 | rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); |
Mike Christie | 0e75f90 | 2006-12-01 10:40:55 +0100 | [diff] [blame] | 2087 | rq->data_len = bio->bi_size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2088 | |
| 2089 | rq->bio = rq->biotail = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2090 | |
NeilBrown | 6684657 | 2007-08-16 13:31:28 +0200 | [diff] [blame] | 2091 | if (bio->bi_bdev) |
| 2092 | rq->rq_disk = bio->bi_bdev->bd_disk; |
| 2093 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2094 | |
Kiyoshi Ueda | ef9e3fa | 2008-10-01 16:12:15 +0200 | [diff] [blame] | 2095 | /** |
| 2096 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy |
| 2097 | * @q : the queue of the device being checked |
| 2098 | * |
| 2099 | * Description: |
| 2100 | * Check if underlying low-level drivers of a device are busy. |
| 2101 | * If the drivers want to export their busy state, they must set own |
| 2102 | * exporting function using blk_queue_lld_busy() first. |
| 2103 | * |
| 2104 | * Basically, this function is used only by request stacking drivers |
| 2105 | * to stop dispatching requests to underlying devices when underlying |
| 2106 | * devices are busy. This behavior helps more I/O merging on the queue |
| 2107 | * of the request stacking driver and prevents I/O throughput regression |
| 2108 | * on burst I/O load. |
| 2109 | * |
| 2110 | * Return: |
| 2111 | * 0 - Not busy (The request stacking driver should dispatch request) |
| 2112 | * 1 - Busy (The request stacking driver should stop dispatching request) |
| 2113 | */ |
| 2114 | int blk_lld_busy(struct request_queue *q) |
| 2115 | { |
| 2116 | if (q->lld_busy_fn) |
| 2117 | return q->lld_busy_fn(q); |
| 2118 | |
| 2119 | return 0; |
| 2120 | } |
| 2121 | EXPORT_SYMBOL_GPL(blk_lld_busy); |
| 2122 | |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame] | 2123 | int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2124 | { |
| 2125 | return queue_work(kblockd_workqueue, work); |
| 2126 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2127 | EXPORT_SYMBOL(kblockd_schedule_work); |
| 2128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2129 | int __init blk_dev_init(void) |
| 2130 | { |
| 2131 | kblockd_workqueue = create_workqueue("kblockd"); |
| 2132 | if (!kblockd_workqueue) |
| 2133 | panic("Failed to create kblockd\n"); |
| 2134 | |
| 2135 | request_cachep = kmem_cache_create("blkdev_requests", |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 2136 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2137 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 2138 | blk_requestq_cachep = kmem_cache_create("blkdev_queue", |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2139 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2140 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2141 | return 0; |
| 2142 | } |
| 2143 | |