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 | faccbd4b | 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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 32 | #include "blk.h" |
| 33 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 34 | static int __make_request(struct request_queue *q, struct bio *bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
| 36 | /* |
| 37 | * For the allocated request tables |
| 38 | */ |
Adrian Bunk | 5ece6c5 | 2008-02-18 13:45:51 +0100 | [diff] [blame] | 39 | static struct kmem_cache *request_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
| 41 | /* |
| 42 | * For queue allocation |
| 43 | */ |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 44 | struct kmem_cache *blk_requestq_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
| 46 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | * Controlling structure to kblockd |
| 48 | */ |
Jens Axboe | ff856ba | 2006-01-09 16:02:34 +0100 | [diff] [blame] | 49 | static struct workqueue_struct *kblockd_workqueue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 51 | static void drive_stat_acct(struct request *rq, int new_io) |
| 52 | { |
Jens Axboe | 28f1370 | 2008-05-07 10:15:46 +0200 | [diff] [blame] | 53 | struct hd_struct *part; |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 54 | int rw = rq_data_dir(rq); |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 55 | int cpu; |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 56 | |
| 57 | if (!blk_fs_request(rq) || !rq->rq_disk) |
| 58 | return; |
| 59 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 60 | cpu = part_stat_lock(); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 61 | part = disk_map_sector_rcu(rq->rq_disk, rq->sector); |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 62 | |
Jens Axboe | 28f1370 | 2008-05-07 10:15:46 +0200 | [diff] [blame] | 63 | if (!new_io) |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 64 | part_stat_inc(cpu, part, merges[rw]); |
Jens Axboe | 28f1370 | 2008-05-07 10:15:46 +0200 | [diff] [blame] | 65 | else { |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 66 | part_round_stats(cpu, part); |
| 67 | part_inc_in_flight(part); |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 68 | } |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 69 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 70 | part_stat_unlock(); |
Jens Axboe | 26b8256 | 2008-01-29 13:54:41 +0100 | [diff] [blame] | 71 | } |
| 72 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 73 | void blk_queue_congestion_threshold(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | { |
| 75 | int nr; |
| 76 | |
| 77 | nr = q->nr_requests - (q->nr_requests / 8) + 1; |
| 78 | if (nr > q->nr_requests) |
| 79 | nr = q->nr_requests; |
| 80 | q->nr_congestion_on = nr; |
| 81 | |
| 82 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; |
| 83 | if (nr < 1) |
| 84 | nr = 1; |
| 85 | q->nr_congestion_off = nr; |
| 86 | } |
| 87 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | /** |
| 89 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info |
| 90 | * @bdev: device |
| 91 | * |
| 92 | * Locates the passed device's request queue and returns the address of its |
| 93 | * backing_dev_info |
| 94 | * |
| 95 | * Will return NULL if the request queue cannot be located. |
| 96 | */ |
| 97 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) |
| 98 | { |
| 99 | struct backing_dev_info *ret = NULL; |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 100 | struct request_queue *q = bdev_get_queue(bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | |
| 102 | if (q) |
| 103 | ret = &q->backing_dev_info; |
| 104 | return ret; |
| 105 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | EXPORT_SYMBOL(blk_get_backing_dev_info); |
| 107 | |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 108 | void blk_rq_init(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | { |
FUJITA Tomonori | 1afb20f | 2008-04-25 12:26:28 +0200 | [diff] [blame] | 110 | memset(rq, 0, sizeof(*rq)); |
| 111 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | INIT_LIST_HEAD(&rq->queuelist); |
Jens Axboe | ff856ba | 2006-01-09 16:02:34 +0100 | [diff] [blame] | 113 | INIT_LIST_HEAD(&rq->donelist); |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 114 | rq->q = q; |
| 115 | rq->sector = rq->hard_sector = (sector_t) -1; |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 116 | INIT_HLIST_NODE(&rq->hash); |
| 117 | RB_CLEAR_NODE(&rq->rb_node); |
FUJITA Tomonori | d7e3c32 | 2008-04-29 09:54:39 +0200 | [diff] [blame] | 118 | rq->cmd = rq->__cmd; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 119 | rq->tag = -1; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 120 | rq->ref_count = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | } |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 122 | EXPORT_SYMBOL(blk_rq_init); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 124 | static void req_bio_endio(struct request *rq, struct bio *bio, |
| 125 | unsigned int nbytes, int error) |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 126 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 127 | struct request_queue *q = rq->q; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 128 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 129 | if (&q->bar_rq != rq) { |
| 130 | if (error) |
| 131 | clear_bit(BIO_UPTODATE, &bio->bi_flags); |
| 132 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) |
| 133 | error = -EIO; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 134 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 135 | if (unlikely(nbytes > bio->bi_size)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 136 | printk(KERN_ERR "%s: want %u bytes done, %u left\n", |
Harvey Harrison | 24c03d4 | 2008-05-01 04:35:17 -0700 | [diff] [blame] | 137 | __func__, nbytes, bio->bi_size); |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 138 | nbytes = bio->bi_size; |
| 139 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 140 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 141 | bio->bi_size -= nbytes; |
| 142 | bio->bi_sector += (nbytes >> 9); |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 143 | |
| 144 | if (bio_integrity(bio)) |
| 145 | bio_integrity_advance(bio, nbytes); |
| 146 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 147 | if (bio->bi_size == 0) |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 148 | bio_endio(bio, error); |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 149 | } else { |
| 150 | |
| 151 | /* |
| 152 | * Okay, this is the barrier request in progress, just |
| 153 | * record the error; |
| 154 | */ |
| 155 | if (error && !q->orderr) |
| 156 | q->orderr = error; |
| 157 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 158 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | void blk_dump_rq_flags(struct request *rq, char *msg) |
| 161 | { |
| 162 | int bit; |
| 163 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 164 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%x\n", msg, |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 165 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, |
| 166 | rq->cmd_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 168 | printk(KERN_INFO " sector %llu, nr/cnr %lu/%u\n", |
| 169 | (unsigned long long)rq->sector, |
| 170 | rq->nr_sectors, |
| 171 | rq->current_nr_sectors); |
| 172 | printk(KERN_INFO " bio %p, biotail %p, buffer %p, data %p, len %u\n", |
| 173 | rq->bio, rq->biotail, |
| 174 | rq->buffer, rq->data, |
| 175 | rq->data_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 177 | if (blk_pc_request(rq)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 178 | printk(KERN_INFO " cdb: "); |
FUJITA Tomonori | d34c87e | 2008-04-29 14:37:52 +0200 | [diff] [blame] | 179 | for (bit = 0; bit < BLK_MAX_CDB; bit++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | printk("%02x ", rq->cmd[bit]); |
| 181 | printk("\n"); |
| 182 | } |
| 183 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | EXPORT_SYMBOL(blk_dump_rq_flags); |
| 185 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | /* |
| 187 | * "plug" the device if there are no outstanding requests: this will |
| 188 | * force the transfer to start only after we have put all the requests |
| 189 | * on the list. |
| 190 | * |
| 191 | * This is called with interrupts off and no requests on the queue and |
| 192 | * with the queue lock held. |
| 193 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 194 | void blk_plug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | { |
| 196 | WARN_ON(!irqs_disabled()); |
| 197 | |
| 198 | /* |
| 199 | * don't plug a stopped queue, it must be paired with blk_start_queue() |
| 200 | * which will restart the queueing |
| 201 | */ |
Coywolf Qi Hunt | 7daac49 | 2006-04-19 10:14:49 +0200 | [diff] [blame] | 202 | if (blk_queue_stopped(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | return; |
| 204 | |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 205 | if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 207 | blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG); |
| 208 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | EXPORT_SYMBOL(blk_plug_device); |
| 211 | |
Jens Axboe | 6c5e0c4 | 2008-08-01 20:31:32 +0200 | [diff] [blame] | 212 | /** |
| 213 | * blk_plug_device_unlocked - plug a device without queue lock held |
| 214 | * @q: The &struct request_queue to plug |
| 215 | * |
| 216 | * Description: |
| 217 | * Like @blk_plug_device(), but grabs the queue lock and disables |
| 218 | * interrupts. |
| 219 | **/ |
| 220 | void blk_plug_device_unlocked(struct request_queue *q) |
| 221 | { |
| 222 | unsigned long flags; |
| 223 | |
| 224 | spin_lock_irqsave(q->queue_lock, flags); |
| 225 | blk_plug_device(q); |
| 226 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 227 | } |
| 228 | EXPORT_SYMBOL(blk_plug_device_unlocked); |
| 229 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | /* |
| 231 | * remove the queue from the plugged list, if present. called with |
| 232 | * queue lock held and interrupts disabled. |
| 233 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 234 | int blk_remove_plug(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | { |
| 236 | WARN_ON(!irqs_disabled()); |
| 237 | |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 238 | if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | return 0; |
| 240 | |
| 241 | del_timer(&q->unplug_timer); |
| 242 | return 1; |
| 243 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | EXPORT_SYMBOL(blk_remove_plug); |
| 245 | |
| 246 | /* |
| 247 | * remove the plug and let it rip.. |
| 248 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 249 | void __generic_unplug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | { |
Coywolf Qi Hunt | 7daac49 | 2006-04-19 10:14:49 +0200 | [diff] [blame] | 251 | if (unlikely(blk_queue_stopped(q))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | return; |
| 253 | |
| 254 | if (!blk_remove_plug(q)) |
| 255 | return; |
| 256 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 257 | q->request_fn(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | } |
| 259 | EXPORT_SYMBOL(__generic_unplug_device); |
| 260 | |
| 261 | /** |
| 262 | * generic_unplug_device - fire a request queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 263 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | * |
| 265 | * Description: |
| 266 | * Linux uses plugging to build bigger requests queues before letting |
| 267 | * the device have at them. If a queue is plugged, the I/O scheduler |
| 268 | * is still adding and merging requests on the queue. Once the queue |
| 269 | * gets unplugged, the request_fn defined for the queue is invoked and |
| 270 | * transfers started. |
| 271 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 272 | void generic_unplug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | { |
Jens Axboe | dbaf2c0 | 2008-05-07 09:48:17 +0200 | [diff] [blame] | 274 | if (blk_queue_plugged(q)) { |
| 275 | spin_lock_irq(q->queue_lock); |
| 276 | __generic_unplug_device(q); |
| 277 | spin_unlock_irq(q->queue_lock); |
| 278 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | } |
| 280 | EXPORT_SYMBOL(generic_unplug_device); |
| 281 | |
| 282 | static void blk_backing_dev_unplug(struct backing_dev_info *bdi, |
| 283 | struct page *page) |
| 284 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 285 | struct request_queue *q = bdi->unplug_io_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 287 | blk_unplug(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | } |
| 289 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 290 | void blk_unplug_work(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 292 | struct request_queue *q = |
| 293 | container_of(work, struct request_queue, unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 295 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL, |
| 296 | q->rq.count[READ] + q->rq.count[WRITE]); |
| 297 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | q->unplug_fn(q); |
| 299 | } |
| 300 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 301 | void blk_unplug_timeout(unsigned long data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 303 | struct request_queue *q = (struct request_queue *)data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 305 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL, |
| 306 | q->rq.count[READ] + q->rq.count[WRITE]); |
| 307 | |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame^] | 308 | kblockd_schedule_work(q, &q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | } |
| 310 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 311 | void blk_unplug(struct request_queue *q) |
| 312 | { |
| 313 | /* |
| 314 | * devices don't necessarily have an ->unplug_fn defined |
| 315 | */ |
| 316 | if (q->unplug_fn) { |
| 317 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL, |
| 318 | q->rq.count[READ] + q->rq.count[WRITE]); |
| 319 | |
| 320 | q->unplug_fn(q); |
| 321 | } |
| 322 | } |
| 323 | EXPORT_SYMBOL(blk_unplug); |
| 324 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | /** |
| 326 | * blk_start_queue - restart a previously stopped queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 327 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | * |
| 329 | * Description: |
| 330 | * blk_start_queue() will clear the stop flag on the queue, and call |
| 331 | * the request_fn for the queue if it was in a stopped state when |
| 332 | * entered. Also see blk_stop_queue(). Queue lock must be held. |
| 333 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 334 | void blk_start_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | { |
Paolo 'Blaisorblade' Giarrusso | a038e25 | 2006-06-05 12:09:01 +0200 | [diff] [blame] | 336 | WARN_ON(!irqs_disabled()); |
| 337 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 338 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | |
| 340 | /* |
| 341 | * one level of recursion is ok and is much faster than kicking |
| 342 | * the unplug handling |
| 343 | */ |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 344 | if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | q->request_fn(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 346 | queue_flag_clear(QUEUE_FLAG_REENTER, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | } else { |
| 348 | blk_plug_device(q); |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame^] | 349 | kblockd_schedule_work(q, &q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | } |
| 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); |
Oleg Nesterov | abbeb88 | 2007-10-23 15:08:19 +0200 | [diff] [blame] | 392 | kblockd_flush_work(&q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | } |
| 394 | EXPORT_SYMBOL(blk_sync_queue); |
| 395 | |
| 396 | /** |
| 397 | * blk_run_queue - run a single device queue |
| 398 | * @q: The queue to run |
| 399 | */ |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 400 | void __blk_run_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | blk_remove_plug(q); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 403 | |
| 404 | /* |
| 405 | * Only recurse once to avoid overrunning the stack, let the unplug |
| 406 | * handling reinvoke the handler shortly if we already got there. |
| 407 | */ |
| 408 | if (!elv_queue_empty(q)) { |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 409 | if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 410 | q->request_fn(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 411 | queue_flag_clear(QUEUE_FLAG_REENTER, q); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 412 | } else { |
| 413 | blk_plug_device(q); |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame^] | 414 | kblockd_schedule_work(q, &q->unplug_work); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 415 | } |
| 416 | } |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 417 | } |
| 418 | EXPORT_SYMBOL(__blk_run_queue); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 419 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 420 | /** |
| 421 | * blk_run_queue - run a single device queue |
| 422 | * @q: The queue to run |
| 423 | */ |
| 424 | void blk_run_queue(struct request_queue *q) |
| 425 | { |
| 426 | unsigned long flags; |
| 427 | |
| 428 | spin_lock_irqsave(q->queue_lock, flags); |
| 429 | __blk_run_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 431 | } |
| 432 | EXPORT_SYMBOL(blk_run_queue); |
| 433 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 434 | void blk_put_queue(struct request_queue *q) |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 435 | { |
| 436 | kobject_put(&q->kobj); |
| 437 | } |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 438 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 439 | void blk_cleanup_queue(struct request_queue *q) |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 440 | { |
| 441 | mutex_lock(&q->sysfs_lock); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 442 | queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 443 | mutex_unlock(&q->sysfs_lock); |
| 444 | |
| 445 | if (q->elevator) |
| 446 | elevator_exit(q->elevator); |
| 447 | |
| 448 | blk_put_queue(q); |
| 449 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | EXPORT_SYMBOL(blk_cleanup_queue); |
| 451 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 452 | static int blk_init_free_list(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | { |
| 454 | struct request_list *rl = &q->rq; |
| 455 | |
| 456 | rl->count[READ] = rl->count[WRITE] = 0; |
| 457 | rl->starved[READ] = rl->starved[WRITE] = 0; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 458 | rl->elvpriv = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | init_waitqueue_head(&rl->wait[READ]); |
| 460 | init_waitqueue_head(&rl->wait[WRITE]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 462 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
| 463 | mempool_free_slab, request_cachep, q->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | |
| 465 | if (!rl->rq_pool) |
| 466 | return -ENOMEM; |
| 467 | |
| 468 | return 0; |
| 469 | } |
| 470 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 471 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | { |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 473 | return blk_alloc_queue_node(gfp_mask, -1); |
| 474 | } |
| 475 | EXPORT_SYMBOL(blk_alloc_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 477 | 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] | 478 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 479 | struct request_queue *q; |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 480 | int err; |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 481 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 482 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 483 | gfp_mask | __GFP_ZERO, node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | if (!q) |
| 485 | return NULL; |
| 486 | |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 487 | q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; |
| 488 | q->backing_dev_info.unplug_io_data = q; |
| 489 | err = bdi_init(&q->backing_dev_info); |
| 490 | if (err) { |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 491 | kmem_cache_free(blk_requestq_cachep, q); |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 492 | return NULL; |
| 493 | } |
| 494 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | init_timer(&q->unplug_timer); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 496 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 497 | kobject_init(&q->kobj, &blk_queue_ktype); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 499 | mutex_init(&q->sysfs_lock); |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 500 | spin_lock_init(&q->__queue_lock); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 501 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | return q; |
| 503 | } |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 504 | EXPORT_SYMBOL(blk_alloc_queue_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | |
| 506 | /** |
| 507 | * blk_init_queue - prepare a request queue for use with a block device |
| 508 | * @rfn: The function to be called to process requests that have been |
| 509 | * placed on the queue. |
| 510 | * @lock: Request queue spin lock |
| 511 | * |
| 512 | * Description: |
| 513 | * If a block device wishes to use the standard request handling procedures, |
| 514 | * which sorts requests and coalesces adjacent requests, then it must |
| 515 | * call blk_init_queue(). The function @rfn will be called when there |
| 516 | * are requests on the queue that need to be processed. If the device |
| 517 | * supports plugging, then @rfn may not be called immediately when requests |
| 518 | * are available on the queue, but may be called at some time later instead. |
| 519 | * Plugged queues are generally unplugged when a buffer belonging to one |
| 520 | * of the requests on the queue is needed, or due to memory pressure. |
| 521 | * |
| 522 | * @rfn is not required, or even expected, to remove all requests off the |
| 523 | * queue, but only as many as it can handle at a time. If it does leave |
| 524 | * requests on the queue, it is responsible for arranging that the requests |
| 525 | * get dealt with eventually. |
| 526 | * |
| 527 | * 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] | 528 | * request queue; this lock will be taken also from interrupt context, so irq |
| 529 | * disabling is needed for it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 531 | * Function returns a pointer to the initialized request queue, or %NULL if |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | * it didn't succeed. |
| 533 | * |
| 534 | * Note: |
| 535 | * blk_init_queue() must be paired with a blk_cleanup_queue() call |
| 536 | * when the block device is deactivated (such as at module unload). |
| 537 | **/ |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 538 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 539 | 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] | 540 | { |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 541 | return blk_init_queue_node(rfn, lock, -1); |
| 542 | } |
| 543 | EXPORT_SYMBOL(blk_init_queue); |
| 544 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 545 | struct request_queue * |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 546 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
| 547 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 548 | struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | |
| 550 | if (!q) |
| 551 | return NULL; |
| 552 | |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 553 | q->node = node_id; |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 554 | if (blk_init_free_list(q)) { |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 555 | kmem_cache_free(blk_requestq_cachep, q); |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 556 | return NULL; |
| 557 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 559 | /* |
| 560 | * if caller didn't supply a lock, they get per-queue locking with |
| 561 | * our embedded lock |
| 562 | */ |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 563 | if (!lock) |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 564 | lock = &q->__queue_lock; |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 565 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | q->request_fn = rfn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | q->prep_rq_fn = NULL; |
| 568 | q->unplug_fn = generic_unplug_device; |
| 569 | q->queue_flags = (1 << QUEUE_FLAG_CLUSTER); |
| 570 | q->queue_lock = lock; |
| 571 | |
| 572 | blk_queue_segment_boundary(q, 0xffffffff); |
| 573 | |
| 574 | blk_queue_make_request(q, __make_request); |
| 575 | blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE); |
| 576 | |
| 577 | blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); |
| 578 | blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); |
| 579 | |
Alan Stern | 44ec954 | 2007-02-20 11:01:57 -0500 | [diff] [blame] | 580 | q->sg_reserved_size = INT_MAX; |
| 581 | |
FUJITA Tomonori | abf5439 | 2008-08-16 14:10:05 +0900 | [diff] [blame] | 582 | blk_set_cmd_filter_defaults(&q->cmd_filter); |
| 583 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | /* |
| 585 | * all done |
| 586 | */ |
| 587 | if (!elevator_init(q, NULL)) { |
| 588 | blk_queue_congestion_threshold(q); |
| 589 | return q; |
| 590 | } |
| 591 | |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 592 | blk_put_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 593 | return NULL; |
| 594 | } |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 595 | EXPORT_SYMBOL(blk_init_queue_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 597 | int blk_get_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | { |
Nick Piggin | fde6ad2 | 2005-06-23 00:08:53 -0700 | [diff] [blame] | 599 | if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 600 | kobject_get(&q->kobj); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | return 0; |
| 602 | } |
| 603 | |
| 604 | return 1; |
| 605 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 607 | 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] | 608 | { |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 609 | if (rq->cmd_flags & REQ_ELVPRIV) |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 610 | elv_put_request(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | mempool_free(rq, q->rq.rq_pool); |
| 612 | } |
| 613 | |
Jens Axboe | 1ea25ecb | 2006-07-18 22:24:11 +0200 | [diff] [blame] | 614 | static struct request * |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 615 | blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | { |
| 617 | struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); |
| 618 | |
| 619 | if (!rq) |
| 620 | return NULL; |
| 621 | |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 622 | blk_rq_init(q, rq); |
FUJITA Tomonori | 1afb20f | 2008-04-25 12:26:28 +0200 | [diff] [blame] | 623 | |
Jens Axboe | 49171e5 | 2006-08-10 08:59:11 +0200 | [diff] [blame] | 624 | rq->cmd_flags = rw | REQ_ALLOCED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 626 | if (priv) { |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 627 | if (unlikely(elv_set_request(q, rq, gfp_mask))) { |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 628 | mempool_free(rq, q->rq.rq_pool); |
| 629 | return NULL; |
| 630 | } |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 631 | rq->cmd_flags |= REQ_ELVPRIV; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 632 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 634 | return rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | } |
| 636 | |
| 637 | /* |
| 638 | * ioc_batching returns true if the ioc is a valid batching request and |
| 639 | * should be given priority access to a request. |
| 640 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 641 | 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] | 642 | { |
| 643 | if (!ioc) |
| 644 | return 0; |
| 645 | |
| 646 | /* |
| 647 | * Make sure the process is able to allocate at least 1 request |
| 648 | * even if the batch times out, otherwise we could theoretically |
| 649 | * lose wakeups. |
| 650 | */ |
| 651 | return ioc->nr_batch_requests == q->nr_batching || |
| 652 | (ioc->nr_batch_requests > 0 |
| 653 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); |
| 654 | } |
| 655 | |
| 656 | /* |
| 657 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This |
| 658 | * will cause the process to be a "batcher" on all queues in the system. This |
| 659 | * is the behaviour we want though - once it gets a wakeup it should be given |
| 660 | * a nice run. |
| 661 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 662 | 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] | 663 | { |
| 664 | if (!ioc || ioc_batching(q, ioc)) |
| 665 | return; |
| 666 | |
| 667 | ioc->nr_batch_requests = q->nr_batching; |
| 668 | ioc->last_waited = jiffies; |
| 669 | } |
| 670 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 671 | static void __freed_request(struct request_queue *q, int rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | { |
| 673 | struct request_list *rl = &q->rq; |
| 674 | |
| 675 | if (rl->count[rw] < queue_congestion_off_threshold(q)) |
Thomas Maier | 79e2de4 | 2006-10-19 23:28:15 -0700 | [diff] [blame] | 676 | blk_clear_queue_congested(q, rw); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | |
| 678 | if (rl->count[rw] + 1 <= q->nr_requests) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | if (waitqueue_active(&rl->wait[rw])) |
| 680 | wake_up(&rl->wait[rw]); |
| 681 | |
| 682 | blk_clear_queue_full(q, rw); |
| 683 | } |
| 684 | } |
| 685 | |
| 686 | /* |
| 687 | * A request has just been released. Account for it, update the full and |
| 688 | * congestion status, wake up any waiters. Called under q->queue_lock. |
| 689 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 690 | static void freed_request(struct request_queue *q, int rw, int priv) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | { |
| 692 | struct request_list *rl = &q->rq; |
| 693 | |
| 694 | rl->count[rw]--; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 695 | if (priv) |
| 696 | rl->elvpriv--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | |
| 698 | __freed_request(q, rw); |
| 699 | |
| 700 | if (unlikely(rl->starved[rw ^ 1])) |
| 701 | __freed_request(q, rw ^ 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | } |
| 703 | |
| 704 | #define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist) |
| 705 | /* |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 706 | * Get a free request, queue_lock must be held. |
| 707 | * Returns NULL on failure, with queue_lock held. |
| 708 | * Returns !NULL on success, with queue_lock *not held*. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 710 | static struct request *get_request(struct request_queue *q, int rw_flags, |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 711 | struct bio *bio, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | { |
| 713 | struct request *rq = NULL; |
| 714 | struct request_list *rl = &q->rq; |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 715 | struct io_context *ioc = NULL; |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 716 | const int rw = rw_flags & 0x01; |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 717 | int may_queue, priv; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 718 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 719 | may_queue = elv_may_queue(q, rw_flags); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 720 | if (may_queue == ELV_MQUEUE_NO) |
| 721 | goto rq_starved; |
| 722 | |
| 723 | if (rl->count[rw]+1 >= queue_congestion_on_threshold(q)) { |
| 724 | if (rl->count[rw]+1 >= q->nr_requests) { |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 725 | ioc = current_io_context(GFP_ATOMIC, q->node); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 726 | /* |
| 727 | * The queue will fill after this allocation, so set |
| 728 | * it as full, and mark this process as "batching". |
| 729 | * This process will be allowed to complete a batch of |
| 730 | * requests, others will be blocked. |
| 731 | */ |
| 732 | if (!blk_queue_full(q, rw)) { |
| 733 | ioc_set_batching(q, ioc); |
| 734 | blk_set_queue_full(q, rw); |
| 735 | } else { |
| 736 | if (may_queue != ELV_MQUEUE_MUST |
| 737 | && !ioc_batching(q, ioc)) { |
| 738 | /* |
| 739 | * The queue is full and the allocating |
| 740 | * process is not a "batcher", and not |
| 741 | * exempted by the IO scheduler |
| 742 | */ |
| 743 | goto out; |
| 744 | } |
| 745 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | } |
Thomas Maier | 79e2de4 | 2006-10-19 23:28:15 -0700 | [diff] [blame] | 747 | blk_set_queue_congested(q, rw); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | } |
| 749 | |
Jens Axboe | 082cf69 | 2005-06-28 16:35:11 +0200 | [diff] [blame] | 750 | /* |
| 751 | * Only allow batching queuers to allocate up to 50% over the defined |
| 752 | * limit of requests, otherwise we could have thousands of requests |
| 753 | * allocated with any setting of ->nr_requests |
| 754 | */ |
Hugh Dickins | fd782a4 | 2005-06-29 15:15:40 +0100 | [diff] [blame] | 755 | if (rl->count[rw] >= (3 * q->nr_requests / 2)) |
Jens Axboe | 082cf69 | 2005-06-28 16:35:11 +0200 | [diff] [blame] | 756 | goto out; |
Hugh Dickins | fd782a4 | 2005-06-29 15:15:40 +0100 | [diff] [blame] | 757 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | rl->count[rw]++; |
| 759 | rl->starved[rw] = 0; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 760 | |
Jens Axboe | 64521d1 | 2005-10-28 08:30:39 +0200 | [diff] [blame] | 761 | priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 762 | if (priv) |
| 763 | rl->elvpriv++; |
| 764 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 765 | spin_unlock_irq(q->queue_lock); |
| 766 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 767 | rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 768 | if (unlikely(!rq)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | /* |
| 770 | * Allocation failed presumably due to memory. Undo anything |
| 771 | * we might have messed up. |
| 772 | * |
| 773 | * Allocating task should really be put onto the front of the |
| 774 | * wait queue, but this is pretty rare. |
| 775 | */ |
| 776 | spin_lock_irq(q->queue_lock); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 777 | freed_request(q, rw, priv); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | |
| 779 | /* |
| 780 | * in the very unlikely event that allocation failed and no |
| 781 | * requests for this direction was pending, mark us starved |
| 782 | * so that freeing of a request in the other direction will |
| 783 | * notice us. another possible fix would be to split the |
| 784 | * rq mempool into READ and WRITE |
| 785 | */ |
| 786 | rq_starved: |
| 787 | if (unlikely(rl->count[rw] == 0)) |
| 788 | rl->starved[rw] = 1; |
| 789 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | goto out; |
| 791 | } |
| 792 | |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 793 | /* |
| 794 | * ioc may be NULL here, and ioc_batching will be false. That's |
| 795 | * OK, if the queue is under the request limit then requests need |
| 796 | * not count toward the nr_batch_requests limit. There will always |
| 797 | * be some limit enforced by BLK_BATCH_TIME. |
| 798 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | if (ioc_batching(q, ioc)) |
| 800 | ioc->nr_batch_requests--; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 801 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 802 | blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 803 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 804 | return rq; |
| 805 | } |
| 806 | |
| 807 | /* |
| 808 | * No available requests for this queue, unplug the device and wait for some |
| 809 | * requests to become available. |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 810 | * |
| 811 | * Called with q->queue_lock held, and returns with it unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 812 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 813 | 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] | 814 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 815 | { |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 816 | const int rw = rw_flags & 0x01; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | struct request *rq; |
| 818 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 819 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 820 | while (!rq) { |
| 821 | DEFINE_WAIT(wait); |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 822 | struct io_context *ioc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 823 | struct request_list *rl = &q->rq; |
| 824 | |
| 825 | prepare_to_wait_exclusive(&rl->wait[rw], &wait, |
| 826 | TASK_UNINTERRUPTIBLE); |
| 827 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 828 | blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 830 | __generic_unplug_device(q); |
| 831 | spin_unlock_irq(q->queue_lock); |
| 832 | io_schedule(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 833 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 834 | /* |
| 835 | * After sleeping, we become a "batching" process and |
| 836 | * will be able to allocate at least one request, and |
| 837 | * up to a big batch of them for a small period time. |
| 838 | * See ioc_batching, ioc_set_batching |
| 839 | */ |
| 840 | ioc = current_io_context(GFP_NOIO, q->node); |
| 841 | ioc_set_batching(q, ioc); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 842 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 843 | spin_lock_irq(q->queue_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | finish_wait(&rl->wait[rw], &wait); |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 845 | |
| 846 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
| 847 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 848 | |
| 849 | return rq; |
| 850 | } |
| 851 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 852 | 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] | 853 | { |
| 854 | struct request *rq; |
| 855 | |
| 856 | BUG_ON(rw != READ && rw != WRITE); |
| 857 | |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 858 | spin_lock_irq(q->queue_lock); |
| 859 | if (gfp_mask & __GFP_WAIT) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 860 | rq = get_request_wait(q, rw, NULL); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 861 | } else { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 862 | rq = get_request(q, rw, NULL, gfp_mask); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 863 | if (!rq) |
| 864 | spin_unlock_irq(q->queue_lock); |
| 865 | } |
| 866 | /* q->queue_lock is unlocked at this point */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | |
| 868 | return rq; |
| 869 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | EXPORT_SYMBOL(blk_get_request); |
| 871 | |
| 872 | /** |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 873 | * blk_start_queueing - initiate dispatch of requests to device |
| 874 | * @q: request queue to kick into gear |
| 875 | * |
| 876 | * This is basically a helper to remove the need to know whether a queue |
| 877 | * is plugged or not if someone just wants to initiate dispatch of requests |
| 878 | * for this queue. |
| 879 | * |
| 880 | * The queue lock must be held with interrupts disabled. |
| 881 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 882 | void blk_start_queueing(struct request_queue *q) |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 883 | { |
| 884 | if (!blk_queue_plugged(q)) |
| 885 | q->request_fn(q); |
| 886 | else |
| 887 | __generic_unplug_device(q); |
| 888 | } |
| 889 | EXPORT_SYMBOL(blk_start_queueing); |
| 890 | |
| 891 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | * blk_requeue_request - put a request back on queue |
| 893 | * @q: request queue where request should be inserted |
| 894 | * @rq: request to be inserted |
| 895 | * |
| 896 | * Description: |
| 897 | * Drivers often keep queueing requests until the hardware cannot accept |
| 898 | * more, when that condition happens we need to put the request back |
| 899 | * on the queue. Must be called with queue lock held. |
| 900 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 901 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | { |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 903 | blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); |
| 904 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 905 | if (blk_rq_tagged(rq)) |
| 906 | blk_queue_end_tag(q, rq); |
| 907 | |
| 908 | elv_requeue_request(q, rq); |
| 909 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | EXPORT_SYMBOL(blk_requeue_request); |
| 911 | |
| 912 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 913 | * blk_insert_request - insert a special request into a request queue |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 914 | * @q: request queue where request should be inserted |
| 915 | * @rq: request to be inserted |
| 916 | * @at_head: insert request at head or tail of queue |
| 917 | * @data: private data |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 918 | * |
| 919 | * Description: |
| 920 | * Many block devices need to execute commands asynchronously, so they don't |
| 921 | * block the whole kernel from preemption during request execution. This is |
| 922 | * accomplished normally by inserting aritficial requests tagged as |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 923 | * REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them |
| 924 | * be scheduled for actual execution by the request queue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | * |
| 926 | * We have the option of inserting the head or the tail of the queue. |
| 927 | * Typically we use the tail for new ioctls and so forth. We use the head |
| 928 | * of the queue for things like a QUEUE_FULL message from a device, or a |
| 929 | * host that is unable to accept a particular command. |
| 930 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 931 | void blk_insert_request(struct request_queue *q, struct request *rq, |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 932 | int at_head, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | { |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 934 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | unsigned long flags; |
| 936 | |
| 937 | /* |
| 938 | * tell I/O scheduler that this isn't a regular read/write (ie it |
| 939 | * must not attempt merges on this) and that it acts as a soft |
| 940 | * barrier |
| 941 | */ |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 942 | rq->cmd_type = REQ_TYPE_SPECIAL; |
| 943 | rq->cmd_flags |= REQ_SOFTBARRIER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 944 | |
| 945 | rq->special = data; |
| 946 | |
| 947 | spin_lock_irqsave(q->queue_lock, flags); |
| 948 | |
| 949 | /* |
| 950 | * If command is tagged, release the tag |
| 951 | */ |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 952 | if (blk_rq_tagged(rq)) |
| 953 | blk_queue_end_tag(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 954 | |
Jerome Marchand | b238b3d | 2007-10-23 15:05:46 +0200 | [diff] [blame] | 955 | drive_stat_acct(rq, 1); |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 956 | __elv_add_request(q, rq, where, 0); |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 957 | blk_start_queueing(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 959 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 960 | EXPORT_SYMBOL(blk_insert_request); |
| 961 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | /* |
| 963 | * add-request adds a request to the linked list. |
| 964 | * queue lock is held and interrupts disabled, as we muck with the |
| 965 | * request queue list. |
| 966 | */ |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 967 | static inline void add_request(struct request_queue *q, struct request *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 968 | { |
Jerome Marchand | b238b3d | 2007-10-23 15:05:46 +0200 | [diff] [blame] | 969 | drive_stat_acct(req, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | /* |
| 972 | * elevator indicated where it wants this request to be |
| 973 | * inserted at elevator_merge time |
| 974 | */ |
| 975 | __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0); |
| 976 | } |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 977 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 978 | static void part_round_stats_single(int cpu, struct hd_struct *part, |
| 979 | unsigned long now) |
| 980 | { |
| 981 | if (now == part->stamp) |
| 982 | return; |
| 983 | |
| 984 | if (part->in_flight) { |
| 985 | __part_stat_add(cpu, part, time_in_queue, |
| 986 | part->in_flight * (now - part->stamp)); |
| 987 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
| 988 | } |
| 989 | part->stamp = now; |
| 990 | } |
| 991 | |
| 992 | /** |
| 993 | * part_round_stats() - Round off the performance stats on a struct |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 994 | * disk_stats. |
| 995 | * |
| 996 | * The average IO queue length and utilisation statistics are maintained |
| 997 | * by observing the current state of the queue length and the amount of |
| 998 | * time it has been in this state for. |
| 999 | * |
| 1000 | * Normally, that accounting is done on IO completion, but that can result |
| 1001 | * in more than a second's worth of IO being accounted for within any one |
| 1002 | * second, leading to >100% utilisation. To deal with that, we call this |
| 1003 | * function to do a round-off before returning the results when reading |
| 1004 | * /proc/diskstats. This accounts immediately for all queue usage up to |
| 1005 | * the current jiffies and restarts the counters again. |
| 1006 | */ |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1007 | void part_round_stats(int cpu, struct hd_struct *part) |
Jerome Marchand | 6f2576af | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1008 | { |
| 1009 | unsigned long now = jiffies; |
| 1010 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1011 | if (part->partno) |
| 1012 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); |
| 1013 | part_round_stats_single(cpu, part, now); |
Jerome Marchand | 6f2576af | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1014 | } |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1015 | EXPORT_SYMBOL_GPL(part_round_stats); |
Jerome Marchand | 6f2576af | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1016 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | /* |
| 1018 | * queue lock must be held |
| 1019 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1020 | void __blk_put_request(struct request_queue *q, struct request *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1021 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1022 | if (unlikely(!q)) |
| 1023 | return; |
| 1024 | if (unlikely(--req->ref_count)) |
| 1025 | return; |
| 1026 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 1027 | elv_completed_request(q, req); |
| 1028 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1029 | /* |
| 1030 | * Request may not have originated from ll_rw_blk. if not, |
| 1031 | * it didn't come out of our reserved rq pools |
| 1032 | */ |
Jens Axboe | 49171e5 | 2006-08-10 08:59:11 +0200 | [diff] [blame] | 1033 | if (req->cmd_flags & REQ_ALLOCED) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1034 | int rw = rq_data_dir(req); |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1035 | int priv = req->cmd_flags & REQ_ELVPRIV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1036 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | BUG_ON(!list_empty(&req->queuelist)); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 1038 | BUG_ON(!hlist_unhashed(&req->hash)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | |
| 1040 | blk_free_request(q, req); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1041 | freed_request(q, rw, priv); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | } |
| 1043 | } |
Mike Christie | 6e39b69 | 2005-11-11 05:30:24 -0600 | [diff] [blame] | 1044 | EXPORT_SYMBOL_GPL(__blk_put_request); |
| 1045 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | void blk_put_request(struct request *req) |
| 1047 | { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 1048 | unsigned long flags; |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1049 | struct request_queue *q = req->q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1050 | |
FUJITA Tomonori | 52a93ba | 2008-07-15 21:21:45 +0200 | [diff] [blame] | 1051 | spin_lock_irqsave(q->queue_lock, flags); |
| 1052 | __blk_put_request(q, req); |
| 1053 | spin_unlock_irqrestore(q->queue_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1054 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1055 | EXPORT_SYMBOL(blk_put_request); |
| 1056 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 1057 | void init_request_from_bio(struct request *req, struct bio *bio) |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1058 | { |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1059 | req->cmd_type = REQ_TYPE_FS; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1060 | |
| 1061 | /* |
| 1062 | * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST) |
| 1063 | */ |
| 1064 | if (bio_rw_ahead(bio) || bio_failfast(bio)) |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1065 | req->cmd_flags |= REQ_FAILFAST; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1066 | |
| 1067 | /* |
| 1068 | * REQ_BARRIER implies no merging, but lets make it explicit |
| 1069 | */ |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1070 | if (unlikely(bio_discard(bio))) { |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1071 | req->cmd_flags |= REQ_DISCARD; |
| 1072 | if (bio_barrier(bio)) |
| 1073 | req->cmd_flags |= REQ_SOFTBARRIER; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1074 | req->q->prepare_discard_fn(req->q, req); |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1075 | } else if (unlikely(bio_barrier(bio))) |
| 1076 | req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1077 | |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 1078 | if (bio_sync(bio)) |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1079 | req->cmd_flags |= REQ_RW_SYNC; |
Jens Axboe | 5404bc7 | 2006-08-10 09:01:02 +0200 | [diff] [blame] | 1080 | if (bio_rw_meta(bio)) |
| 1081 | req->cmd_flags |= REQ_RW_META; |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 1082 | |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1083 | req->errors = 0; |
| 1084 | req->hard_sector = req->sector = bio->bi_sector; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1085 | req->ioprio = bio_prio(bio); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1086 | req->start_time = jiffies; |
NeilBrown | bc1c56f | 2007-08-16 13:31:30 +0200 | [diff] [blame] | 1087 | blk_rq_bio_prep(req->q, req, bio); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1088 | } |
| 1089 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1090 | static int __make_request(struct request_queue *q, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1091 | { |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1092 | struct request *req; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1093 | int el_ret, nr_sectors, barrier, discard, err; |
Jens Axboe | 51da90f | 2006-07-18 04:14:45 +0200 | [diff] [blame] | 1094 | const unsigned short prio = bio_prio(bio); |
| 1095 | const int sync = bio_sync(bio); |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1096 | int rw_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1098 | nr_sectors = bio_sectors(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | |
| 1100 | /* |
| 1101 | * low level driver can indicate that it wants pages above a |
| 1102 | * certain limit bounced to low memory (ie for highmem, or even |
| 1103 | * ISA dma in theory) |
| 1104 | */ |
| 1105 | blk_queue_bounce(q, &bio); |
| 1106 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1107 | barrier = bio_barrier(bio); |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1108 | if (unlikely(barrier) && bio_has_data(bio) && |
| 1109 | (q->next_ordered == QUEUE_ORDERED_NONE)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | err = -EOPNOTSUPP; |
| 1111 | goto end_io; |
| 1112 | } |
| 1113 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1114 | discard = bio_discard(bio); |
| 1115 | if (unlikely(discard) && !q->prepare_discard_fn) { |
| 1116 | err = -EOPNOTSUPP; |
| 1117 | goto end_io; |
| 1118 | } |
| 1119 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1120 | spin_lock_irq(q->queue_lock); |
| 1121 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1122 | if (unlikely(barrier) || elv_queue_empty(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1123 | goto get_rq; |
| 1124 | |
| 1125 | el_ret = elv_merge(q, &req, bio); |
| 1126 | switch (el_ret) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1127 | case ELEVATOR_BACK_MERGE: |
| 1128 | BUG_ON(!rq_mergeable(req)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1130 | if (!ll_back_merge_fn(q, req, bio)) |
| 1131 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1132 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1133 | blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1134 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1135 | req->biotail->bi_next = bio; |
| 1136 | req->biotail = bio; |
| 1137 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
| 1138 | req->ioprio = ioprio_best(req->ioprio, prio); |
| 1139 | drive_stat_acct(req, 0); |
| 1140 | if (!attempt_back_merge(q, req)) |
| 1141 | elv_merged_request(q, req, el_ret); |
| 1142 | goto out; |
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 | case ELEVATOR_FRONT_MERGE: |
| 1145 | BUG_ON(!rq_mergeable(req)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1147 | if (!ll_front_merge_fn(q, req, bio)) |
| 1148 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1149 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1150 | blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1151 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1152 | bio->bi_next = req->bio; |
| 1153 | req->bio = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1155 | /* |
| 1156 | * may not be valid. if the low level driver said |
| 1157 | * it didn't need a bounce buffer then it better |
| 1158 | * not touch req->buffer either... |
| 1159 | */ |
| 1160 | req->buffer = bio_data(bio); |
| 1161 | req->current_nr_sectors = bio_cur_sectors(bio); |
| 1162 | req->hard_cur_sectors = req->current_nr_sectors; |
| 1163 | req->sector = req->hard_sector = bio->bi_sector; |
| 1164 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
| 1165 | req->ioprio = ioprio_best(req->ioprio, prio); |
| 1166 | drive_stat_acct(req, 0); |
| 1167 | if (!attempt_front_merge(q, req)) |
| 1168 | elv_merged_request(q, req, el_ret); |
| 1169 | goto out; |
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 | /* ELV_NO_MERGE: elevator says don't/can't merge. */ |
| 1172 | default: |
| 1173 | ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1174 | } |
| 1175 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | get_rq: |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1177 | /* |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1178 | * This sync check and mask will be re-done in init_request_from_bio(), |
| 1179 | * but we need to set it earlier to expose the sync flag to the |
| 1180 | * rq allocator and io schedulers. |
| 1181 | */ |
| 1182 | rw_flags = bio_data_dir(bio); |
| 1183 | if (sync) |
| 1184 | rw_flags |= REQ_RW_SYNC; |
| 1185 | |
| 1186 | /* |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1187 | * Grab a free request. This is might sleep but can not fail. |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 1188 | * Returns with the queue unlocked. |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1189 | */ |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1190 | req = get_request_wait(q, rw_flags, bio); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 1191 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1192 | /* |
| 1193 | * After dropping the lock and possibly sleeping here, our request |
| 1194 | * may now be mergeable after it had proven unmergeable (above). |
| 1195 | * We don't worry about that case for efficiency. It won't happen |
| 1196 | * often, and the elevators are able to handle it. |
| 1197 | */ |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1198 | init_request_from_bio(req, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1199 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1200 | spin_lock_irq(q->queue_lock); |
| 1201 | if (elv_queue_empty(q)) |
| 1202 | blk_plug_device(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1203 | add_request(q, req); |
| 1204 | out: |
Jens Axboe | 4a534f9 | 2005-04-16 15:25:40 -0700 | [diff] [blame] | 1205 | if (sync) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | __generic_unplug_device(q); |
| 1207 | |
| 1208 | spin_unlock_irq(q->queue_lock); |
| 1209 | return 0; |
| 1210 | |
| 1211 | end_io: |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 1212 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1213 | return 0; |
| 1214 | } |
| 1215 | |
| 1216 | /* |
| 1217 | * If bio->bi_dev is a partition, remap the location |
| 1218 | */ |
| 1219 | static inline void blk_partition_remap(struct bio *bio) |
| 1220 | { |
| 1221 | struct block_device *bdev = bio->bi_bdev; |
| 1222 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1223 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | struct hd_struct *p = bdev->bd_part; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1225 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | bio->bi_sector += p->start_sect; |
| 1227 | bio->bi_bdev = bdev->bd_contains; |
Alan D. Brunelle | c7149d6 | 2007-08-07 15:30:23 +0200 | [diff] [blame] | 1228 | |
| 1229 | blk_add_trace_remap(bdev_get_queue(bio->bi_bdev), bio, |
| 1230 | bdev->bd_dev, bio->bi_sector, |
| 1231 | bio->bi_sector - p->start_sect); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | } |
| 1233 | } |
| 1234 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1235 | static void handle_bad_sector(struct bio *bio) |
| 1236 | { |
| 1237 | char b[BDEVNAME_SIZE]; |
| 1238 | |
| 1239 | printk(KERN_INFO "attempt to access beyond end of device\n"); |
| 1240 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", |
| 1241 | bdevname(bio->bi_bdev, b), |
| 1242 | bio->bi_rw, |
| 1243 | (unsigned long long)bio->bi_sector + bio_sectors(bio), |
| 1244 | (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); |
| 1245 | |
| 1246 | set_bit(BIO_EOF, &bio->bi_flags); |
| 1247 | } |
| 1248 | |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1249 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
| 1250 | |
| 1251 | static DECLARE_FAULT_ATTR(fail_make_request); |
| 1252 | |
| 1253 | static int __init setup_fail_make_request(char *str) |
| 1254 | { |
| 1255 | return setup_fault_attr(&fail_make_request, str); |
| 1256 | } |
| 1257 | __setup("fail_make_request=", setup_fail_make_request); |
| 1258 | |
| 1259 | static int should_fail_request(struct bio *bio) |
| 1260 | { |
Tejun Heo | eddb2e2 | 2008-08-25 19:56:13 +0900 | [diff] [blame] | 1261 | struct hd_struct *part = bio->bi_bdev->bd_part; |
| 1262 | |
| 1263 | 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] | 1264 | return should_fail(&fail_make_request, bio->bi_size); |
| 1265 | |
| 1266 | return 0; |
| 1267 | } |
| 1268 | |
| 1269 | static int __init fail_make_request_debugfs(void) |
| 1270 | { |
| 1271 | return init_fault_attr_dentries(&fail_make_request, |
| 1272 | "fail_make_request"); |
| 1273 | } |
| 1274 | |
| 1275 | late_initcall(fail_make_request_debugfs); |
| 1276 | |
| 1277 | #else /* CONFIG_FAIL_MAKE_REQUEST */ |
| 1278 | |
| 1279 | static inline int should_fail_request(struct bio *bio) |
| 1280 | { |
| 1281 | return 0; |
| 1282 | } |
| 1283 | |
| 1284 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ |
| 1285 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1286 | /* |
| 1287 | * Check whether this bio extends beyond the end of the device. |
| 1288 | */ |
| 1289 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) |
| 1290 | { |
| 1291 | sector_t maxsector; |
| 1292 | |
| 1293 | if (!nr_sectors) |
| 1294 | return 0; |
| 1295 | |
| 1296 | /* Test device or partition size, when known. */ |
| 1297 | maxsector = bio->bi_bdev->bd_inode->i_size >> 9; |
| 1298 | if (maxsector) { |
| 1299 | sector_t sector = bio->bi_sector; |
| 1300 | |
| 1301 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { |
| 1302 | /* |
| 1303 | * This may well happen - the kernel calls bread() |
| 1304 | * without checking the size of the device, e.g., when |
| 1305 | * mounting a device. |
| 1306 | */ |
| 1307 | handle_bad_sector(bio); |
| 1308 | return 1; |
| 1309 | } |
| 1310 | } |
| 1311 | |
| 1312 | return 0; |
| 1313 | } |
| 1314 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1315 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1316 | * 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] | 1317 | * @bio: The bio describing the location in memory and on the device. |
| 1318 | * |
| 1319 | * generic_make_request() is used to make I/O requests of block |
| 1320 | * devices. It is passed a &struct bio, which describes the I/O that needs |
| 1321 | * to be done. |
| 1322 | * |
| 1323 | * generic_make_request() does not return any status. The |
| 1324 | * success/failure status of the request, along with notification of |
| 1325 | * completion, is delivered asynchronously through the bio->bi_end_io |
| 1326 | * function described (one day) else where. |
| 1327 | * |
| 1328 | * The caller of generic_make_request must make sure that bi_io_vec |
| 1329 | * are set to describe the memory buffer, and that bi_dev and bi_sector are |
| 1330 | * set to describe the device address, and the |
| 1331 | * bi_end_io and optionally bi_private are set to describe how |
| 1332 | * completion notification should be signaled. |
| 1333 | * |
| 1334 | * generic_make_request and the drivers it calls may use bi_next if this |
| 1335 | * bio happens to be merged with someone else, and may change bi_dev and |
| 1336 | * bi_sector for remaps as it sees fit. So the values of these fields |
| 1337 | * should NOT be depended on after the call to generic_make_request. |
| 1338 | */ |
Neil Brown | d89d879 | 2007-05-01 09:53:42 +0200 | [diff] [blame] | 1339 | static inline void __generic_make_request(struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1340 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1341 | struct request_queue *q; |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1342 | sector_t old_sector; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1343 | int ret, nr_sectors = bio_sectors(bio); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1344 | dev_t old_dev; |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1345 | int err = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1346 | |
| 1347 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1348 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1349 | if (bio_check_eod(bio, nr_sectors)) |
| 1350 | goto end_io; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1351 | |
| 1352 | /* |
| 1353 | * Resolve the mapping until finished. (drivers are |
| 1354 | * still free to implement/resolve their own stacking |
| 1355 | * by explicitly returning 0) |
| 1356 | * |
| 1357 | * NOTE: we don't repeat the blk_size check for each new device. |
| 1358 | * Stacking drivers are expected to know what they are doing. |
| 1359 | */ |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1360 | old_sector = -1; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1361 | old_dev = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1362 | do { |
| 1363 | char b[BDEVNAME_SIZE]; |
| 1364 | |
| 1365 | q = bdev_get_queue(bio->bi_bdev); |
| 1366 | if (!q) { |
| 1367 | printk(KERN_ERR |
| 1368 | "generic_make_request: Trying to access " |
| 1369 | "nonexistent block-device %s (%Lu)\n", |
| 1370 | bdevname(bio->bi_bdev, b), |
| 1371 | (long long) bio->bi_sector); |
| 1372 | end_io: |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1373 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1374 | break; |
| 1375 | } |
| 1376 | |
Jens Axboe | 4fa253f | 2007-07-18 13:13:10 +0200 | [diff] [blame] | 1377 | if (unlikely(nr_sectors > q->max_hw_sectors)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1378 | printk(KERN_ERR "bio too big device %s (%u > %u)\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1379 | bdevname(bio->bi_bdev, b), |
| 1380 | bio_sectors(bio), |
| 1381 | q->max_hw_sectors); |
| 1382 | goto end_io; |
| 1383 | } |
| 1384 | |
Nick Piggin | fde6ad2 | 2005-06-23 00:08:53 -0700 | [diff] [blame] | 1385 | if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1386 | goto end_io; |
| 1387 | |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1388 | if (should_fail_request(bio)) |
| 1389 | goto end_io; |
| 1390 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1391 | /* |
| 1392 | * If this device has partitions, remap block n |
| 1393 | * of partition p to block n+start(p) of the disk. |
| 1394 | */ |
| 1395 | blk_partition_remap(bio); |
| 1396 | |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 1397 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) |
| 1398 | goto end_io; |
| 1399 | |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1400 | if (old_sector != -1) |
Jens Axboe | 4fa253f | 2007-07-18 13:13:10 +0200 | [diff] [blame] | 1401 | blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1402 | old_sector); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1403 | |
| 1404 | blk_add_trace_bio(q, bio, BLK_TA_QUEUE); |
| 1405 | |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1406 | old_sector = bio->bi_sector; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1407 | old_dev = bio->bi_bdev->bd_dev; |
| 1408 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1409 | if (bio_check_eod(bio, nr_sectors)) |
| 1410 | goto end_io; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1411 | if ((bio_empty_barrier(bio) && !q->prepare_flush_fn) || |
| 1412 | (bio_discard(bio) && !q->prepare_discard_fn)) { |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1413 | err = -EOPNOTSUPP; |
| 1414 | goto end_io; |
| 1415 | } |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1416 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1417 | ret = q->make_request_fn(q, bio); |
| 1418 | } while (ret); |
| 1419 | } |
| 1420 | |
Neil Brown | d89d879 | 2007-05-01 09:53:42 +0200 | [diff] [blame] | 1421 | /* |
| 1422 | * We only want one ->make_request_fn to be active at a time, |
| 1423 | * else stack usage with stacked devices could be a problem. |
| 1424 | * So use current->bio_{list,tail} to keep a list of requests |
| 1425 | * submited by a make_request_fn function. |
| 1426 | * current->bio_tail is also used as a flag to say if |
| 1427 | * generic_make_request is currently active in this task or not. |
| 1428 | * If it is NULL, then no make_request is active. If it is non-NULL, |
| 1429 | * then a make_request is active, and new requests should be added |
| 1430 | * at the tail |
| 1431 | */ |
| 1432 | void generic_make_request(struct bio *bio) |
| 1433 | { |
| 1434 | if (current->bio_tail) { |
| 1435 | /* make_request is active */ |
| 1436 | *(current->bio_tail) = bio; |
| 1437 | bio->bi_next = NULL; |
| 1438 | current->bio_tail = &bio->bi_next; |
| 1439 | return; |
| 1440 | } |
| 1441 | /* following loop may be a bit non-obvious, and so deserves some |
| 1442 | * explanation. |
| 1443 | * Before entering the loop, bio->bi_next is NULL (as all callers |
| 1444 | * ensure that) so we have a list with a single bio. |
| 1445 | * We pretend that we have just taken it off a longer list, so |
| 1446 | * we assign bio_list to the next (which is NULL) and bio_tail |
| 1447 | * to &bio_list, thus initialising the bio_list of new bios to be |
| 1448 | * added. __generic_make_request may indeed add some more bios |
| 1449 | * through a recursive call to generic_make_request. If it |
| 1450 | * did, we find a non-NULL value in bio_list and re-enter the loop |
| 1451 | * from the top. In this case we really did just take the bio |
| 1452 | * of the top of the list (no pretending) and so fixup bio_list and |
| 1453 | * bio_tail or bi_next, and call into __generic_make_request again. |
| 1454 | * |
| 1455 | * The loop was structured like this to make only one call to |
| 1456 | * __generic_make_request (which is important as it is large and |
| 1457 | * inlined) and to keep the structure simple. |
| 1458 | */ |
| 1459 | BUG_ON(bio->bi_next); |
| 1460 | do { |
| 1461 | current->bio_list = bio->bi_next; |
| 1462 | if (bio->bi_next == NULL) |
| 1463 | current->bio_tail = ¤t->bio_list; |
| 1464 | else |
| 1465 | bio->bi_next = NULL; |
| 1466 | __generic_make_request(bio); |
| 1467 | bio = current->bio_list; |
| 1468 | } while (bio); |
| 1469 | current->bio_tail = NULL; /* deactivate */ |
| 1470 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1471 | EXPORT_SYMBOL(generic_make_request); |
| 1472 | |
| 1473 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1474 | * 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] | 1475 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
| 1476 | * @bio: The &struct bio which describes the I/O |
| 1477 | * |
| 1478 | * submit_bio() is very similar in purpose to generic_make_request(), and |
| 1479 | * 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] | 1480 | * interfaces; @bio must be presetup and ready for I/O. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1481 | * |
| 1482 | */ |
| 1483 | void submit_bio(int rw, struct bio *bio) |
| 1484 | { |
| 1485 | int count = bio_sectors(bio); |
| 1486 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1487 | bio->bi_rw |= rw; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1488 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1489 | /* |
| 1490 | * If it's a regular read/write or a barrier with data attached, |
| 1491 | * go through the normal accounting stuff before submission. |
| 1492 | */ |
Jens Axboe | a9c701e | 2008-08-08 11:04:44 +0200 | [diff] [blame] | 1493 | if (bio_has_data(bio)) { |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1494 | if (rw & WRITE) { |
| 1495 | count_vm_events(PGPGOUT, count); |
| 1496 | } else { |
| 1497 | task_io_account_read(bio->bi_size); |
| 1498 | count_vm_events(PGPGIN, count); |
| 1499 | } |
| 1500 | |
| 1501 | if (unlikely(block_dump)) { |
| 1502 | char b[BDEVNAME_SIZE]; |
| 1503 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1504 | current->comm, task_pid_nr(current), |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1505 | (rw & WRITE) ? "WRITE" : "READ", |
| 1506 | (unsigned long long)bio->bi_sector, |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1507 | bdevname(bio->bi_bdev, b)); |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1508 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1509 | } |
| 1510 | |
| 1511 | generic_make_request(bio); |
| 1512 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1513 | EXPORT_SYMBOL(submit_bio); |
| 1514 | |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1515 | /** |
| 1516 | * __end_that_request_first - end I/O on a request |
| 1517 | * @req: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1518 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1519 | * @nr_bytes: number of bytes to complete |
| 1520 | * |
| 1521 | * Description: |
| 1522 | * Ends I/O on a number of bytes attached to @req, and sets it up |
| 1523 | * for the next range of segments (if any) in the cluster. |
| 1524 | * |
| 1525 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1526 | * %0 - we are done with this request, call end_that_request_last() |
| 1527 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1528 | **/ |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1529 | static int __end_that_request_first(struct request *req, int error, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1530 | int nr_bytes) |
| 1531 | { |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1532 | int total_bytes, bio_nbytes, next_idx = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1533 | struct bio *bio; |
| 1534 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1535 | blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE); |
| 1536 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1537 | /* |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1538 | * for a REQ_TYPE_BLOCK_PC request, we want to carry any eventual |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1539 | * sense key with us all the way through |
| 1540 | */ |
| 1541 | if (!blk_pc_request(req)) |
| 1542 | req->errors = 0; |
| 1543 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1544 | if (error && (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))) { |
| 1545 | 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] | 1546 | req->rq_disk ? req->rq_disk->disk_name : "?", |
| 1547 | (unsigned long long)req->sector); |
| 1548 | } |
| 1549 | |
Jens Axboe | d72d904 | 2005-11-01 08:35:42 +0100 | [diff] [blame] | 1550 | if (blk_fs_request(req) && req->rq_disk) { |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1551 | const int rw = rq_data_dir(req); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1552 | struct hd_struct *part; |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1553 | int cpu; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1554 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1555 | cpu = part_stat_lock(); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1556 | part = disk_map_sector_rcu(req->rq_disk, req->sector); |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1557 | part_stat_add(cpu, part, sectors[rw], nr_bytes >> 9); |
| 1558 | part_stat_unlock(); |
Jens Axboe | d72d904 | 2005-11-01 08:35:42 +0100 | [diff] [blame] | 1559 | } |
| 1560 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1561 | total_bytes = bio_nbytes = 0; |
| 1562 | while ((bio = req->bio) != NULL) { |
| 1563 | int nbytes; |
| 1564 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1565 | /* |
| 1566 | * For an empty barrier request, the low level driver must |
| 1567 | * store a potential error location in ->sector. We pass |
| 1568 | * that back up in ->bi_sector. |
| 1569 | */ |
| 1570 | if (blk_empty_barrier(req)) |
| 1571 | bio->bi_sector = req->sector; |
| 1572 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1573 | if (nr_bytes >= bio->bi_size) { |
| 1574 | req->bio = bio->bi_next; |
| 1575 | nbytes = bio->bi_size; |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 1576 | req_bio_endio(req, bio, nbytes, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1577 | next_idx = 0; |
| 1578 | bio_nbytes = 0; |
| 1579 | } else { |
| 1580 | int idx = bio->bi_idx + next_idx; |
| 1581 | |
| 1582 | if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { |
| 1583 | blk_dump_rq_flags(req, "__end_that"); |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1584 | printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n", |
Harvey Harrison | 24c03d4 | 2008-05-01 04:35:17 -0700 | [diff] [blame] | 1585 | __func__, bio->bi_idx, bio->bi_vcnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1586 | break; |
| 1587 | } |
| 1588 | |
| 1589 | nbytes = bio_iovec_idx(bio, idx)->bv_len; |
| 1590 | BIO_BUG_ON(nbytes > bio->bi_size); |
| 1591 | |
| 1592 | /* |
| 1593 | * not a complete bvec done |
| 1594 | */ |
| 1595 | if (unlikely(nbytes > nr_bytes)) { |
| 1596 | bio_nbytes += nr_bytes; |
| 1597 | total_bytes += nr_bytes; |
| 1598 | break; |
| 1599 | } |
| 1600 | |
| 1601 | /* |
| 1602 | * advance to the next vector |
| 1603 | */ |
| 1604 | next_idx++; |
| 1605 | bio_nbytes += nbytes; |
| 1606 | } |
| 1607 | |
| 1608 | total_bytes += nbytes; |
| 1609 | nr_bytes -= nbytes; |
| 1610 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1611 | bio = req->bio; |
| 1612 | if (bio) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1613 | /* |
| 1614 | * end more in this run, or just return 'not-done' |
| 1615 | */ |
| 1616 | if (unlikely(nr_bytes <= 0)) |
| 1617 | break; |
| 1618 | } |
| 1619 | } |
| 1620 | |
| 1621 | /* |
| 1622 | * completely done |
| 1623 | */ |
| 1624 | if (!req->bio) |
| 1625 | return 0; |
| 1626 | |
| 1627 | /* |
| 1628 | * if the request wasn't completed, update state |
| 1629 | */ |
| 1630 | if (bio_nbytes) { |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 1631 | req_bio_endio(req, bio, bio_nbytes, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1632 | bio->bi_idx += next_idx; |
| 1633 | bio_iovec(bio)->bv_offset += nr_bytes; |
| 1634 | bio_iovec(bio)->bv_len -= nr_bytes; |
| 1635 | } |
| 1636 | |
| 1637 | blk_recalc_rq_sectors(req, total_bytes >> 9); |
| 1638 | blk_recalc_rq_segments(req); |
| 1639 | return 1; |
| 1640 | } |
| 1641 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1642 | /* |
| 1643 | * queue lock must be held |
| 1644 | */ |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1645 | static void end_that_request_last(struct request *req, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1646 | { |
| 1647 | struct gendisk *disk = req->rq_disk; |
Tejun Heo | 8ffdc65 | 2006-01-06 09:49:03 +0100 | [diff] [blame] | 1648 | |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1649 | if (blk_rq_tagged(req)) |
| 1650 | blk_queue_end_tag(req->q, req); |
| 1651 | |
| 1652 | if (blk_queued_rq(req)) |
| 1653 | blkdev_dequeue_request(req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1654 | |
| 1655 | if (unlikely(laptop_mode) && blk_fs_request(req)) |
| 1656 | laptop_io_completion(); |
| 1657 | |
Jens Axboe | fd0ff8a | 2006-05-23 11:23:49 +0200 | [diff] [blame] | 1658 | /* |
| 1659 | * Account IO completion. bar_rq isn't accounted as a normal |
| 1660 | * IO on queueing nor completion. Accounting the containing |
| 1661 | * request is enough. |
| 1662 | */ |
| 1663 | if (disk && blk_fs_request(req) && req != &req->q->bar_rq) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1664 | unsigned long duration = jiffies - req->start_time; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1665 | const int rw = rq_data_dir(req); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1666 | struct hd_struct *part; |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1667 | int cpu; |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1668 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1669 | cpu = part_stat_lock(); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1670 | part = disk_map_sector_rcu(disk, req->sector); |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1671 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1672 | part_stat_inc(cpu, part, ios[rw]); |
| 1673 | part_stat_add(cpu, part, ticks[rw], duration); |
| 1674 | part_round_stats(cpu, part); |
| 1675 | part_dec_in_flight(part); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1676 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1677 | part_stat_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1678 | } |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1679 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1680 | if (req->end_io) |
Tejun Heo | 8ffdc65 | 2006-01-06 09:49:03 +0100 | [diff] [blame] | 1681 | req->end_io(req, error); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1682 | else { |
| 1683 | if (blk_bidi_rq(req)) |
| 1684 | __blk_put_request(req->next_rq->q, req->next_rq); |
| 1685 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | __blk_put_request(req->q, req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1687 | } |
| 1688 | } |
| 1689 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1690 | static inline void __end_request(struct request *rq, int uptodate, |
Kiyoshi Ueda | 9e6e39f | 2007-12-11 17:41:54 -0500 | [diff] [blame] | 1691 | unsigned int nr_bytes) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1692 | { |
Kiyoshi Ueda | 9e6e39f | 2007-12-11 17:41:54 -0500 | [diff] [blame] | 1693 | int error = 0; |
| 1694 | |
| 1695 | if (uptodate <= 0) |
| 1696 | error = uptodate ? uptodate : -EIO; |
| 1697 | |
| 1698 | __blk_end_request(rq, error, nr_bytes); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1699 | } |
| 1700 | |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1701 | /** |
| 1702 | * blk_rq_bytes - Returns bytes left to complete in the entire request |
Randy Dunlap | 5d87a05 | 2008-02-20 09:01:22 +0100 | [diff] [blame] | 1703 | * @rq: the request being processed |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1704 | **/ |
| 1705 | unsigned int blk_rq_bytes(struct request *rq) |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1706 | { |
| 1707 | if (blk_fs_request(rq)) |
| 1708 | return rq->hard_nr_sectors << 9; |
| 1709 | |
| 1710 | return rq->data_len; |
| 1711 | } |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1712 | EXPORT_SYMBOL_GPL(blk_rq_bytes); |
| 1713 | |
| 1714 | /** |
| 1715 | * 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] | 1716 | * @rq: the request being processed |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1717 | **/ |
| 1718 | unsigned int blk_rq_cur_bytes(struct request *rq) |
| 1719 | { |
| 1720 | if (blk_fs_request(rq)) |
| 1721 | return rq->current_nr_sectors << 9; |
| 1722 | |
| 1723 | if (rq->bio) |
| 1724 | return rq->bio->bi_size; |
| 1725 | |
| 1726 | return rq->data_len; |
| 1727 | } |
| 1728 | EXPORT_SYMBOL_GPL(blk_rq_cur_bytes); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1729 | |
| 1730 | /** |
| 1731 | * end_queued_request - end all I/O on a queued request |
| 1732 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1733 | * @uptodate: error value or %0/%1 uptodate flag |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1734 | * |
| 1735 | * Description: |
| 1736 | * Ends all I/O on a request, and removes it from the block layer queues. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1737 | * Not suitable for normal I/O completion, unless the driver still has |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1738 | * the request attached to the block layer. |
| 1739 | * |
| 1740 | **/ |
| 1741 | void end_queued_request(struct request *rq, int uptodate) |
| 1742 | { |
Kiyoshi Ueda | 9e6e39f | 2007-12-11 17:41:54 -0500 | [diff] [blame] | 1743 | __end_request(rq, uptodate, blk_rq_bytes(rq)); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1744 | } |
| 1745 | EXPORT_SYMBOL(end_queued_request); |
| 1746 | |
| 1747 | /** |
| 1748 | * end_dequeued_request - end all I/O on a dequeued request |
| 1749 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1750 | * @uptodate: error value or %0/%1 uptodate flag |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1751 | * |
| 1752 | * Description: |
| 1753 | * Ends all I/O on a request. The request must already have been |
| 1754 | * dequeued using blkdev_dequeue_request(), as is normally the case |
| 1755 | * for most drivers. |
| 1756 | * |
| 1757 | **/ |
| 1758 | void end_dequeued_request(struct request *rq, int uptodate) |
| 1759 | { |
Kiyoshi Ueda | 9e6e39f | 2007-12-11 17:41:54 -0500 | [diff] [blame] | 1760 | __end_request(rq, uptodate, blk_rq_bytes(rq)); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1761 | } |
| 1762 | EXPORT_SYMBOL(end_dequeued_request); |
| 1763 | |
| 1764 | |
| 1765 | /** |
| 1766 | * end_request - end I/O on the current segment of the request |
Randy Dunlap | 8f731f7 | 2007-10-18 23:39:28 -0700 | [diff] [blame] | 1767 | * @req: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1768 | * @uptodate: error value or %0/%1 uptodate flag |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1769 | * |
| 1770 | * Description: |
| 1771 | * Ends I/O on the current segment of a request. If that is the only |
| 1772 | * remaining segment, the request is also completed and freed. |
| 1773 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1774 | * This is a remnant of how older block drivers handled I/O completions. |
| 1775 | * 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] | 1776 | * they have a residual value to account for. For that case this function |
| 1777 | * isn't really useful, unless the residual just happens to be the |
| 1778 | * full current segment. In other words, don't use this function in new |
| 1779 | * code. Either use end_request_completely(), or the |
| 1780 | * end_that_request_chunk() (along with end_that_request_last()) for |
| 1781 | * partial completions. |
| 1782 | * |
| 1783 | **/ |
| 1784 | void end_request(struct request *req, int uptodate) |
| 1785 | { |
Kiyoshi Ueda | 9e6e39f | 2007-12-11 17:41:54 -0500 | [diff] [blame] | 1786 | __end_request(req, uptodate, req->hard_cur_sectors << 9); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1787 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1788 | EXPORT_SYMBOL(end_request); |
| 1789 | |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1790 | /** |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1791 | * blk_end_io - Generic end_io function to complete a request. |
| 1792 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1793 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1794 | * @nr_bytes: number of bytes to complete @rq |
| 1795 | * @bidi_bytes: number of bytes to complete @rq->next_rq |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1796 | * @drv_callback: function called between completion of bios in the request |
| 1797 | * and completion of the request. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1798 | * If the callback returns non %0, this helper returns without |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1799 | * completion of the request. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1800 | * |
| 1801 | * Description: |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1802 | * 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] | 1803 | * If @rq has leftover, sets it up for the next range of segments. |
| 1804 | * |
| 1805 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1806 | * %0 - we are done with this request |
| 1807 | * %1 - this request is not freed yet, it still has pending buffers. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1808 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1809 | static int blk_end_io(struct request *rq, int error, unsigned int nr_bytes, |
| 1810 | unsigned int bidi_bytes, |
| 1811 | int (drv_callback)(struct request *)) |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1812 | { |
| 1813 | struct request_queue *q = rq->q; |
| 1814 | unsigned long flags = 0UL; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1815 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1816 | if (bio_has_data(rq->bio) || blk_discard_rq(rq)) { |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1817 | if (__end_that_request_first(rq, error, nr_bytes)) |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1818 | return 1; |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1819 | |
| 1820 | /* Bidi request must be completed as a whole */ |
| 1821 | if (blk_bidi_rq(rq) && |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1822 | __end_that_request_first(rq->next_rq, error, bidi_bytes)) |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1823 | return 1; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1824 | } |
| 1825 | |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1826 | /* Special feature for tricky drivers */ |
| 1827 | if (drv_callback && drv_callback(rq)) |
| 1828 | return 1; |
| 1829 | |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1830 | add_disk_randomness(rq->rq_disk); |
| 1831 | |
| 1832 | spin_lock_irqsave(q->queue_lock, flags); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1833 | end_that_request_last(rq, error); |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1834 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1835 | |
| 1836 | return 0; |
| 1837 | } |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1838 | |
| 1839 | /** |
| 1840 | * blk_end_request - Helper function for drivers to complete the request. |
| 1841 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1842 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1843 | * @nr_bytes: number of bytes to complete |
| 1844 | * |
| 1845 | * Description: |
| 1846 | * Ends I/O on a number of bytes attached to @rq. |
| 1847 | * If @rq has leftover, sets it up for the next range of segments. |
| 1848 | * |
| 1849 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1850 | * %0 - we are done with this request |
| 1851 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1852 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1853 | 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] | 1854 | { |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1855 | return blk_end_io(rq, error, nr_bytes, 0, NULL); |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1856 | } |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1857 | EXPORT_SYMBOL_GPL(blk_end_request); |
| 1858 | |
| 1859 | /** |
| 1860 | * __blk_end_request - Helper function for drivers to complete the request. |
| 1861 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1862 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1863 | * @nr_bytes: number of bytes to complete |
| 1864 | * |
| 1865 | * Description: |
| 1866 | * Must be called with queue lock held unlike blk_end_request(). |
| 1867 | * |
| 1868 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1869 | * %0 - we are done with this request |
| 1870 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1871 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1872 | 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] | 1873 | { |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1874 | if ((bio_has_data(rq->bio) || blk_discard_rq(rq)) && |
Jens Axboe | 051cc39 | 2008-08-08 11:06:45 +0200 | [diff] [blame] | 1875 | __end_that_request_first(rq, error, nr_bytes)) |
| 1876 | return 1; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1877 | |
| 1878 | add_disk_randomness(rq->rq_disk); |
| 1879 | |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1880 | end_that_request_last(rq, error); |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1881 | |
| 1882 | return 0; |
| 1883 | } |
| 1884 | EXPORT_SYMBOL_GPL(__blk_end_request); |
| 1885 | |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1886 | /** |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1887 | * blk_end_bidi_request - Helper function for drivers to complete bidi request. |
| 1888 | * @rq: the bidi request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1889 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1890 | * @nr_bytes: number of bytes to complete @rq |
| 1891 | * @bidi_bytes: number of bytes to complete @rq->next_rq |
| 1892 | * |
| 1893 | * Description: |
| 1894 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
| 1895 | * |
| 1896 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1897 | * %0 - we are done with this request |
| 1898 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1899 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1900 | int blk_end_bidi_request(struct request *rq, int error, unsigned int nr_bytes, |
| 1901 | unsigned int bidi_bytes) |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1902 | { |
| 1903 | return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL); |
| 1904 | } |
| 1905 | EXPORT_SYMBOL_GPL(blk_end_bidi_request); |
| 1906 | |
| 1907 | /** |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1908 | * blk_end_request_callback - Special helper function for tricky drivers |
| 1909 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1910 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1911 | * @nr_bytes: number of bytes to complete |
| 1912 | * @drv_callback: function called between completion of bios in the request |
| 1913 | * and completion of the request. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1914 | * If the callback returns non %0, this helper returns without |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1915 | * completion of the request. |
| 1916 | * |
| 1917 | * Description: |
| 1918 | * Ends I/O on a number of bytes attached to @rq. |
| 1919 | * If @rq has leftover, sets it up for the next range of segments. |
| 1920 | * |
| 1921 | * This special helper function is used only for existing tricky drivers. |
| 1922 | * (e.g. cdrom_newpc_intr() of ide-cd) |
| 1923 | * This interface will be removed when such drivers are rewritten. |
| 1924 | * Don't use this interface in other places anymore. |
| 1925 | * |
| 1926 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1927 | * %0 - we are done with this request |
| 1928 | * %1 - this request is not freed yet. |
| 1929 | * this request still has pending buffers or |
| 1930 | * the driver doesn't want to finish this request yet. |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1931 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1932 | int blk_end_request_callback(struct request *rq, int error, |
| 1933 | unsigned int nr_bytes, |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1934 | int (drv_callback)(struct request *)) |
| 1935 | { |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1936 | return blk_end_io(rq, error, nr_bytes, 0, drv_callback); |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1937 | } |
| 1938 | EXPORT_SYMBOL_GPL(blk_end_request_callback); |
| 1939 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 1940 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
| 1941 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1942 | { |
David Woodhouse | d628eae | 2008-08-09 16:22:17 +0100 | [diff] [blame] | 1943 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw, and |
| 1944 | 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] | 1945 | rq->cmd_flags |= (bio->bi_rw & 3); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1946 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1947 | if (bio_has_data(bio)) { |
| 1948 | rq->nr_phys_segments = bio_phys_segments(q, bio); |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1949 | rq->buffer = bio_data(bio); |
| 1950 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1951 | rq->current_nr_sectors = bio_cur_sectors(bio); |
| 1952 | rq->hard_cur_sectors = rq->current_nr_sectors; |
| 1953 | rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); |
Mike Christie | 0e75f90 | 2006-12-01 10:40:55 +0100 | [diff] [blame] | 1954 | rq->data_len = bio->bi_size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1955 | |
| 1956 | rq->bio = rq->biotail = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1957 | |
NeilBrown | 6684657 | 2007-08-16 13:31:28 +0200 | [diff] [blame] | 1958 | if (bio->bi_bdev) |
| 1959 | rq->rq_disk = bio->bi_bdev->bd_disk; |
| 1960 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1961 | |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame^] | 1962 | int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1963 | { |
| 1964 | return queue_work(kblockd_workqueue, work); |
| 1965 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1966 | EXPORT_SYMBOL(kblockd_schedule_work); |
| 1967 | |
Andrew Morton | 19a75d8 | 2007-05-09 02:33:56 -0700 | [diff] [blame] | 1968 | void kblockd_flush_work(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1969 | { |
Oleg Nesterov | 28e53bd | 2007-05-09 02:34:22 -0700 | [diff] [blame] | 1970 | cancel_work_sync(work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1971 | } |
Andrew Morton | 19a75d8 | 2007-05-09 02:33:56 -0700 | [diff] [blame] | 1972 | EXPORT_SYMBOL(kblockd_flush_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1973 | |
| 1974 | int __init blk_dev_init(void) |
| 1975 | { |
| 1976 | kblockd_workqueue = create_workqueue("kblockd"); |
| 1977 | if (!kblockd_workqueue) |
| 1978 | panic("Failed to create kblockd\n"); |
| 1979 | |
| 1980 | request_cachep = kmem_cache_create("blkdev_requests", |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 1981 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1982 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 1983 | blk_requestq_cachep = kmem_cache_create("blkdev_queue", |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1984 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1985 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1986 | return 0; |
| 1987 | } |
| 1988 | |