Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 3 | * Copyright (C) 1994, Karl Keyte: Added support for disk statistics |
| 4 | * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| 5 | * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
| 7 | * - July2000 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 |
| 9 | */ |
| 10 | |
| 11 | /* |
| 12 | * This handles all read/write requests to block devices |
| 13 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/kernel.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/backing-dev.h> |
| 17 | #include <linux/bio.h> |
| 18 | #include <linux/blkdev.h> |
| 19 | #include <linux/highmem.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/kernel_stat.h> |
| 22 | #include <linux/string.h> |
| 23 | #include <linux/init.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/completion.h> |
| 25 | #include <linux/slab.h> |
| 26 | #include <linux/swap.h> |
| 27 | #include <linux/writeback.h> |
Andrew Morton | faccbd4 | 2006-12-10 02:19:35 -0800 | [diff] [blame] | 28 | #include <linux/task_io_accounting_ops.h> |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 29 | #include <linux/blktrace_api.h> |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 30 | #include <linux/fault-inject.h> |
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 | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 113 | INIT_LIST_HEAD(&rq->timeout_list); |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 114 | rq->cpu = -1; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 115 | rq->q = q; |
| 116 | rq->sector = rq->hard_sector = (sector_t) -1; |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 117 | INIT_HLIST_NODE(&rq->hash); |
| 118 | RB_CLEAR_NODE(&rq->rb_node); |
FUJITA Tomonori | d7e3c32 | 2008-04-29 09:54:39 +0200 | [diff] [blame] | 119 | rq->cmd = rq->__cmd; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 120 | rq->tag = -1; |
Jens Axboe | 63a7138 | 2008-02-08 12:41:03 +0100 | [diff] [blame] | 121 | rq->ref_count = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | } |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 123 | EXPORT_SYMBOL(blk_rq_init); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 125 | static void req_bio_endio(struct request *rq, struct bio *bio, |
| 126 | unsigned int nbytes, int error) |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 127 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 128 | struct request_queue *q = rq->q; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 129 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 130 | if (&q->bar_rq != rq) { |
| 131 | if (error) |
| 132 | clear_bit(BIO_UPTODATE, &bio->bi_flags); |
| 133 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) |
| 134 | error = -EIO; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 135 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 136 | if (unlikely(nbytes > bio->bi_size)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 137 | printk(KERN_ERR "%s: want %u bytes done, %u left\n", |
Harvey Harrison | 24c03d4 | 2008-05-01 04:35:17 -0700 | [diff] [blame] | 138 | __func__, nbytes, bio->bi_size); |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 139 | nbytes = bio->bi_size; |
| 140 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 141 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 142 | bio->bi_size -= nbytes; |
| 143 | bio->bi_sector += (nbytes >> 9); |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 144 | |
| 145 | if (bio_integrity(bio)) |
| 146 | bio_integrity_advance(bio, nbytes); |
| 147 | |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 148 | if (bio->bi_size == 0) |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 149 | bio_endio(bio, error); |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 150 | } else { |
| 151 | |
| 152 | /* |
| 153 | * Okay, this is the barrier request in progress, just |
| 154 | * record the error; |
| 155 | */ |
| 156 | if (error && !q->orderr) |
| 157 | q->orderr = error; |
| 158 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 159 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | void blk_dump_rq_flags(struct request *rq, char *msg) |
| 162 | { |
| 163 | int bit; |
| 164 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 165 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%x\n", msg, |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 166 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, |
| 167 | rq->cmd_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 169 | printk(KERN_INFO " sector %llu, nr/cnr %lu/%u\n", |
| 170 | (unsigned long long)rq->sector, |
| 171 | rq->nr_sectors, |
| 172 | rq->current_nr_sectors); |
| 173 | printk(KERN_INFO " bio %p, biotail %p, buffer %p, data %p, len %u\n", |
| 174 | rq->bio, rq->biotail, |
| 175 | rq->buffer, rq->data, |
| 176 | rq->data_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 178 | if (blk_pc_request(rq)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 179 | printk(KERN_INFO " cdb: "); |
FUJITA Tomonori | d34c87e | 2008-04-29 14:37:52 +0200 | [diff] [blame] | 180 | for (bit = 0; bit < BLK_MAX_CDB; bit++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | printk("%02x ", rq->cmd[bit]); |
| 182 | printk("\n"); |
| 183 | } |
| 184 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | EXPORT_SYMBOL(blk_dump_rq_flags); |
| 186 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | /* |
| 188 | * "plug" the device if there are no outstanding requests: this will |
| 189 | * force the transfer to start only after we have put all the requests |
| 190 | * on the list. |
| 191 | * |
| 192 | * This is called with interrupts off and no requests on the queue and |
| 193 | * with the queue lock held. |
| 194 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 195 | void blk_plug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | { |
| 197 | WARN_ON(!irqs_disabled()); |
| 198 | |
| 199 | /* |
| 200 | * don't plug a stopped queue, it must be paired with blk_start_queue() |
| 201 | * which will restart the queueing |
| 202 | */ |
Coywolf Qi Hunt | 7daac49 | 2006-04-19 10:14:49 +0200 | [diff] [blame] | 203 | if (blk_queue_stopped(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | return; |
| 205 | |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 206 | if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 208 | blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG); |
| 209 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | EXPORT_SYMBOL(blk_plug_device); |
| 212 | |
Jens Axboe | 6c5e0c4 | 2008-08-01 20:31:32 +0200 | [diff] [blame] | 213 | /** |
| 214 | * blk_plug_device_unlocked - plug a device without queue lock held |
| 215 | * @q: The &struct request_queue to plug |
| 216 | * |
| 217 | * Description: |
| 218 | * Like @blk_plug_device(), but grabs the queue lock and disables |
| 219 | * interrupts. |
| 220 | **/ |
| 221 | void blk_plug_device_unlocked(struct request_queue *q) |
| 222 | { |
| 223 | unsigned long flags; |
| 224 | |
| 225 | spin_lock_irqsave(q->queue_lock, flags); |
| 226 | blk_plug_device(q); |
| 227 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 228 | } |
| 229 | EXPORT_SYMBOL(blk_plug_device_unlocked); |
| 230 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | /* |
| 232 | * remove the queue from the plugged list, if present. called with |
| 233 | * queue lock held and interrupts disabled. |
| 234 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 235 | int blk_remove_plug(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | { |
| 237 | WARN_ON(!irqs_disabled()); |
| 238 | |
Jens Axboe | e48ec69 | 2008-07-03 13:18:54 +0200 | [diff] [blame] | 239 | if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | return 0; |
| 241 | |
| 242 | del_timer(&q->unplug_timer); |
| 243 | return 1; |
| 244 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | EXPORT_SYMBOL(blk_remove_plug); |
| 246 | |
| 247 | /* |
| 248 | * remove the plug and let it rip.. |
| 249 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 250 | void __generic_unplug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | { |
Coywolf Qi Hunt | 7daac49 | 2006-04-19 10:14:49 +0200 | [diff] [blame] | 252 | if (unlikely(blk_queue_stopped(q))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | return; |
| 254 | |
| 255 | if (!blk_remove_plug(q)) |
| 256 | return; |
| 257 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 258 | q->request_fn(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 259 | } |
| 260 | EXPORT_SYMBOL(__generic_unplug_device); |
| 261 | |
| 262 | /** |
| 263 | * generic_unplug_device - fire a request queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 264 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | * |
| 266 | * Description: |
| 267 | * Linux uses plugging to build bigger requests queues before letting |
| 268 | * the device have at them. If a queue is plugged, the I/O scheduler |
| 269 | * is still adding and merging requests on the queue. Once the queue |
| 270 | * gets unplugged, the request_fn defined for the queue is invoked and |
| 271 | * transfers started. |
| 272 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 273 | void generic_unplug_device(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | { |
Jens Axboe | dbaf2c0 | 2008-05-07 09:48:17 +0200 | [diff] [blame] | 275 | if (blk_queue_plugged(q)) { |
| 276 | spin_lock_irq(q->queue_lock); |
| 277 | __generic_unplug_device(q); |
| 278 | spin_unlock_irq(q->queue_lock); |
| 279 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | } |
| 281 | EXPORT_SYMBOL(generic_unplug_device); |
| 282 | |
| 283 | static void blk_backing_dev_unplug(struct backing_dev_info *bdi, |
| 284 | struct page *page) |
| 285 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 286 | struct request_queue *q = bdi->unplug_io_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 288 | blk_unplug(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | } |
| 290 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 291 | void blk_unplug_work(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 293 | struct request_queue *q = |
| 294 | container_of(work, struct request_queue, unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 296 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL, |
| 297 | q->rq.count[READ] + q->rq.count[WRITE]); |
| 298 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | q->unplug_fn(q); |
| 300 | } |
| 301 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 302 | void blk_unplug_timeout(unsigned long data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 303 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 304 | struct request_queue *q = (struct request_queue *)data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 306 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL, |
| 307 | q->rq.count[READ] + q->rq.count[WRITE]); |
| 308 | |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame] | 309 | kblockd_schedule_work(q, &q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | } |
| 311 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 312 | void blk_unplug(struct request_queue *q) |
| 313 | { |
| 314 | /* |
| 315 | * devices don't necessarily have an ->unplug_fn defined |
| 316 | */ |
| 317 | if (q->unplug_fn) { |
| 318 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL, |
| 319 | q->rq.count[READ] + q->rq.count[WRITE]); |
| 320 | |
| 321 | q->unplug_fn(q); |
| 322 | } |
| 323 | } |
| 324 | EXPORT_SYMBOL(blk_unplug); |
| 325 | |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 326 | static void blk_invoke_request_fn(struct request_queue *q) |
| 327 | { |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 328 | if (unlikely(blk_queue_stopped(q))) |
| 329 | return; |
| 330 | |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 331 | /* |
| 332 | * one level of recursion is ok and is much faster than kicking |
| 333 | * the unplug handling |
| 334 | */ |
| 335 | if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { |
| 336 | q->request_fn(q); |
| 337 | queue_flag_clear(QUEUE_FLAG_REENTER, q); |
| 338 | } else { |
| 339 | queue_flag_set(QUEUE_FLAG_PLUGGED, q); |
| 340 | kblockd_schedule_work(q, &q->unplug_work); |
| 341 | } |
| 342 | } |
| 343 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | /** |
| 345 | * blk_start_queue - restart a previously stopped queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 346 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | * |
| 348 | * Description: |
| 349 | * blk_start_queue() will clear the stop flag on the queue, and call |
| 350 | * the request_fn for the queue if it was in a stopped state when |
| 351 | * entered. Also see blk_stop_queue(). Queue lock must be held. |
| 352 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 353 | void blk_start_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 354 | { |
Paolo 'Blaisorblade' Giarrusso | a038e25 | 2006-06-05 12:09:01 +0200 | [diff] [blame] | 355 | WARN_ON(!irqs_disabled()); |
| 356 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 357 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 358 | blk_invoke_request_fn(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | EXPORT_SYMBOL(blk_start_queue); |
| 361 | |
| 362 | /** |
| 363 | * blk_stop_queue - stop a queue |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 364 | * @q: The &struct request_queue in question |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | * |
| 366 | * Description: |
| 367 | * The Linux block layer assumes that a block driver will consume all |
| 368 | * entries on the request queue when the request_fn strategy is called. |
| 369 | * Often this will not happen, because of hardware limitations (queue |
| 370 | * depth settings). If a device driver gets a 'queue full' response, |
| 371 | * or if it simply chooses not to queue more I/O at one point, it can |
| 372 | * call this function to prevent the request_fn from being called until |
| 373 | * the driver has signalled it's ready to go again. This happens by calling |
| 374 | * blk_start_queue() to restart queue operations. Queue lock must be held. |
| 375 | **/ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 376 | void blk_stop_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | { |
| 378 | blk_remove_plug(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 379 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | } |
| 381 | EXPORT_SYMBOL(blk_stop_queue); |
| 382 | |
| 383 | /** |
| 384 | * blk_sync_queue - cancel any pending callbacks on a queue |
| 385 | * @q: the queue |
| 386 | * |
| 387 | * Description: |
| 388 | * The block layer may perform asynchronous callback activity |
| 389 | * on a queue, such as calling the unplug function after a timeout. |
| 390 | * A block device may call blk_sync_queue to ensure that any |
| 391 | * such activity is cancelled, thus allowing it to release resources |
Michael Opdenacker | 59c5159 | 2007-05-09 08:57:56 +0200 | [diff] [blame] | 392 | * that the callbacks might use. The caller must already have made sure |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | * that its ->make_request_fn will not re-add plugging prior to calling |
| 394 | * this function. |
| 395 | * |
| 396 | */ |
| 397 | void blk_sync_queue(struct request_queue *q) |
| 398 | { |
| 399 | del_timer_sync(&q->unplug_timer); |
Oleg Nesterov | abbeb88 | 2007-10-23 15:08:19 +0200 | [diff] [blame] | 400 | kblockd_flush_work(&q->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | } |
| 402 | EXPORT_SYMBOL(blk_sync_queue); |
| 403 | |
| 404 | /** |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 405 | * __blk_run_queue - run a single device queue |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | * @q: The queue to run |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 407 | * |
| 408 | * Description: |
| 409 | * See @blk_run_queue. This variant must be called with the queue lock |
| 410 | * held and interrupts disabled. |
| 411 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | */ |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 413 | void __blk_run_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | blk_remove_plug(q); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 416 | |
| 417 | /* |
| 418 | * Only recurse once to avoid overrunning the stack, let the unplug |
| 419 | * handling reinvoke the handler shortly if we already got there. |
| 420 | */ |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 421 | if (!elv_queue_empty(q)) |
| 422 | blk_invoke_request_fn(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 423 | } |
| 424 | EXPORT_SYMBOL(__blk_run_queue); |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 425 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 426 | /** |
| 427 | * blk_run_queue - run a single device queue |
| 428 | * @q: The queue to run |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 429 | * |
| 430 | * Description: |
| 431 | * Invoke request handling on this queue, if it has pending work to do. |
| 432 | * May be used to restart queueing when a request has completed. Also |
| 433 | * See @blk_start_queueing. |
| 434 | * |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 435 | */ |
| 436 | void blk_run_queue(struct request_queue *q) |
| 437 | { |
| 438 | unsigned long flags; |
| 439 | |
| 440 | spin_lock_irqsave(q->queue_lock, flags); |
| 441 | __blk_run_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 443 | } |
| 444 | EXPORT_SYMBOL(blk_run_queue); |
| 445 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 446 | void blk_put_queue(struct request_queue *q) |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 447 | { |
| 448 | kobject_put(&q->kobj); |
| 449 | } |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 450 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 451 | void blk_cleanup_queue(struct request_queue *q) |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 452 | { |
Jens Axboe | e3335de | 2008-09-18 09:22:54 -0700 | [diff] [blame] | 453 | /* |
| 454 | * We know we have process context here, so we can be a little |
| 455 | * cautious and ensure that pending block actions on this device |
| 456 | * are done before moving on. Going into this function, we should |
| 457 | * not have processes doing IO to this device. |
| 458 | */ |
| 459 | blk_sync_queue(q); |
| 460 | |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 461 | mutex_lock(&q->sysfs_lock); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 462 | queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 463 | mutex_unlock(&q->sysfs_lock); |
| 464 | |
| 465 | if (q->elevator) |
| 466 | elevator_exit(q->elevator); |
| 467 | |
| 468 | blk_put_queue(q); |
| 469 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | EXPORT_SYMBOL(blk_cleanup_queue); |
| 471 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 472 | static int blk_init_free_list(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 473 | { |
| 474 | struct request_list *rl = &q->rq; |
| 475 | |
| 476 | rl->count[READ] = rl->count[WRITE] = 0; |
| 477 | rl->starved[READ] = rl->starved[WRITE] = 0; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 478 | rl->elvpriv = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 479 | init_waitqueue_head(&rl->wait[READ]); |
| 480 | init_waitqueue_head(&rl->wait[WRITE]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 482 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
| 483 | mempool_free_slab, request_cachep, q->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | |
| 485 | if (!rl->rq_pool) |
| 486 | return -ENOMEM; |
| 487 | |
| 488 | return 0; |
| 489 | } |
| 490 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 491 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | { |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 493 | return blk_alloc_queue_node(gfp_mask, -1); |
| 494 | } |
| 495 | EXPORT_SYMBOL(blk_alloc_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 497 | 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] | 498 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 499 | struct request_queue *q; |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 500 | int err; |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 501 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 502 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 503 | gfp_mask | __GFP_ZERO, node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | if (!q) |
| 505 | return NULL; |
| 506 | |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 507 | q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; |
| 508 | q->backing_dev_info.unplug_io_data = q; |
| 509 | err = bdi_init(&q->backing_dev_info); |
| 510 | if (err) { |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 511 | kmem_cache_free(blk_requestq_cachep, q); |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 512 | return NULL; |
| 513 | } |
| 514 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | init_timer(&q->unplug_timer); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 516 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); |
| 517 | INIT_LIST_HEAD(&q->timeout_list); |
Peter Zijlstra | 713ada9 | 2008-10-16 13:44:57 +0200 | [diff] [blame^] | 518 | INIT_WORK(&q->unplug_work, blk_unplug_work); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 519 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 520 | kobject_init(&q->kobj, &blk_queue_ktype); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 522 | mutex_init(&q->sysfs_lock); |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 523 | spin_lock_init(&q->__queue_lock); |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 524 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | return q; |
| 526 | } |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 527 | EXPORT_SYMBOL(blk_alloc_queue_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | |
| 529 | /** |
| 530 | * blk_init_queue - prepare a request queue for use with a block device |
| 531 | * @rfn: The function to be called to process requests that have been |
| 532 | * placed on the queue. |
| 533 | * @lock: Request queue spin lock |
| 534 | * |
| 535 | * Description: |
| 536 | * If a block device wishes to use the standard request handling procedures, |
| 537 | * which sorts requests and coalesces adjacent requests, then it must |
| 538 | * call blk_init_queue(). The function @rfn will be called when there |
| 539 | * are requests on the queue that need to be processed. If the device |
| 540 | * supports plugging, then @rfn may not be called immediately when requests |
| 541 | * are available on the queue, but may be called at some time later instead. |
| 542 | * Plugged queues are generally unplugged when a buffer belonging to one |
| 543 | * of the requests on the queue is needed, or due to memory pressure. |
| 544 | * |
| 545 | * @rfn is not required, or even expected, to remove all requests off the |
| 546 | * queue, but only as many as it can handle at a time. If it does leave |
| 547 | * requests on the queue, it is responsible for arranging that the requests |
| 548 | * get dealt with eventually. |
| 549 | * |
| 550 | * 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] | 551 | * request queue; this lock will be taken also from interrupt context, so irq |
| 552 | * disabling is needed for it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 554 | * Function returns a pointer to the initialized request queue, or %NULL if |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | * it didn't succeed. |
| 556 | * |
| 557 | * Note: |
| 558 | * blk_init_queue() must be paired with a blk_cleanup_queue() call |
| 559 | * when the block device is deactivated (such as at module unload). |
| 560 | **/ |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 561 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 562 | 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] | 563 | { |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 564 | return blk_init_queue_node(rfn, lock, -1); |
| 565 | } |
| 566 | EXPORT_SYMBOL(blk_init_queue); |
| 567 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 568 | struct request_queue * |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 569 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
| 570 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 571 | struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 572 | |
| 573 | if (!q) |
| 574 | return NULL; |
| 575 | |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 576 | q->node = node_id; |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 577 | if (blk_init_free_list(q)) { |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 578 | kmem_cache_free(blk_requestq_cachep, q); |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 579 | return NULL; |
| 580 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 582 | /* |
| 583 | * if caller didn't supply a lock, they get per-queue locking with |
| 584 | * our embedded lock |
| 585 | */ |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 586 | if (!lock) |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 587 | lock = &q->__queue_lock; |
| 152587d | 2005-04-12 16:22:06 -0500 | [diff] [blame] | 588 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | q->request_fn = rfn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | q->prep_rq_fn = NULL; |
| 591 | q->unplug_fn = generic_unplug_device; |
Kiyoshi Ueda | 4ee5eaf | 2008-09-18 10:46:13 -0400 | [diff] [blame] | 592 | q->queue_flags = (1 << QUEUE_FLAG_CLUSTER | |
| 593 | 1 << QUEUE_FLAG_STACKABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | q->queue_lock = lock; |
| 595 | |
| 596 | blk_queue_segment_boundary(q, 0xffffffff); |
| 597 | |
| 598 | blk_queue_make_request(q, __make_request); |
| 599 | blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE); |
| 600 | |
| 601 | blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); |
| 602 | blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); |
| 603 | |
Alan Stern | 44ec954 | 2007-02-20 11:01:57 -0500 | [diff] [blame] | 604 | q->sg_reserved_size = INT_MAX; |
| 605 | |
FUJITA Tomonori | abf5439 | 2008-08-16 14:10:05 +0900 | [diff] [blame] | 606 | blk_set_cmd_filter_defaults(&q->cmd_filter); |
| 607 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | /* |
| 609 | * all done |
| 610 | */ |
| 611 | if (!elevator_init(q, NULL)) { |
| 612 | blk_queue_congestion_threshold(q); |
| 613 | return q; |
| 614 | } |
| 615 | |
Al Viro | 8669aaf | 2006-03-18 13:50:00 -0500 | [diff] [blame] | 616 | blk_put_queue(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | return NULL; |
| 618 | } |
Christoph Lameter | 1946089 | 2005-06-23 00:08:19 -0700 | [diff] [blame] | 619 | EXPORT_SYMBOL(blk_init_queue_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 621 | int blk_get_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | { |
Nick Piggin | fde6ad2 | 2005-06-23 00:08:53 -0700 | [diff] [blame] | 623 | if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { |
Al Viro | 483f4af | 2006-03-18 18:34:37 -0500 | [diff] [blame] | 624 | kobject_get(&q->kobj); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | return 0; |
| 626 | } |
| 627 | |
| 628 | return 1; |
| 629 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 631 | 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] | 632 | { |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 633 | if (rq->cmd_flags & REQ_ELVPRIV) |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 634 | elv_put_request(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | mempool_free(rq, q->rq.rq_pool); |
| 636 | } |
| 637 | |
Jens Axboe | 1ea25ec | 2006-07-18 22:24:11 +0200 | [diff] [blame] | 638 | static struct request * |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 639 | 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] | 640 | { |
| 641 | struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); |
| 642 | |
| 643 | if (!rq) |
| 644 | return NULL; |
| 645 | |
FUJITA Tomonori | 2a4aa30 | 2008-04-29 09:54:36 +0200 | [diff] [blame] | 646 | blk_rq_init(q, rq); |
FUJITA Tomonori | 1afb20f | 2008-04-25 12:26:28 +0200 | [diff] [blame] | 647 | |
Jens Axboe | 49171e5 | 2006-08-10 08:59:11 +0200 | [diff] [blame] | 648 | rq->cmd_flags = rw | REQ_ALLOCED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 650 | if (priv) { |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 651 | if (unlikely(elv_set_request(q, rq, gfp_mask))) { |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 652 | mempool_free(rq, q->rq.rq_pool); |
| 653 | return NULL; |
| 654 | } |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 655 | rq->cmd_flags |= REQ_ELVPRIV; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 656 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 658 | return rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | } |
| 660 | |
| 661 | /* |
| 662 | * ioc_batching returns true if the ioc is a valid batching request and |
| 663 | * should be given priority access to a request. |
| 664 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 665 | 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] | 666 | { |
| 667 | if (!ioc) |
| 668 | return 0; |
| 669 | |
| 670 | /* |
| 671 | * Make sure the process is able to allocate at least 1 request |
| 672 | * even if the batch times out, otherwise we could theoretically |
| 673 | * lose wakeups. |
| 674 | */ |
| 675 | return ioc->nr_batch_requests == q->nr_batching || |
| 676 | (ioc->nr_batch_requests > 0 |
| 677 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); |
| 678 | } |
| 679 | |
| 680 | /* |
| 681 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This |
| 682 | * will cause the process to be a "batcher" on all queues in the system. This |
| 683 | * is the behaviour we want though - once it gets a wakeup it should be given |
| 684 | * a nice run. |
| 685 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 686 | 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] | 687 | { |
| 688 | if (!ioc || ioc_batching(q, ioc)) |
| 689 | return; |
| 690 | |
| 691 | ioc->nr_batch_requests = q->nr_batching; |
| 692 | ioc->last_waited = jiffies; |
| 693 | } |
| 694 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 695 | static void __freed_request(struct request_queue *q, int rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 696 | { |
| 697 | struct request_list *rl = &q->rq; |
| 698 | |
| 699 | if (rl->count[rw] < queue_congestion_off_threshold(q)) |
Thomas Maier | 79e2de4 | 2006-10-19 23:28:15 -0700 | [diff] [blame] | 700 | blk_clear_queue_congested(q, rw); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 701 | |
| 702 | if (rl->count[rw] + 1 <= q->nr_requests) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | if (waitqueue_active(&rl->wait[rw])) |
| 704 | wake_up(&rl->wait[rw]); |
| 705 | |
| 706 | blk_clear_queue_full(q, rw); |
| 707 | } |
| 708 | } |
| 709 | |
| 710 | /* |
| 711 | * A request has just been released. Account for it, update the full and |
| 712 | * congestion status, wake up any waiters. Called under q->queue_lock. |
| 713 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 714 | static void freed_request(struct request_queue *q, int rw, int priv) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | { |
| 716 | struct request_list *rl = &q->rq; |
| 717 | |
| 718 | rl->count[rw]--; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 719 | if (priv) |
| 720 | rl->elvpriv--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | |
| 722 | __freed_request(q, rw); |
| 723 | |
| 724 | if (unlikely(rl->starved[rw ^ 1])) |
| 725 | __freed_request(q, rw ^ 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | } |
| 727 | |
| 728 | #define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist) |
| 729 | /* |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 730 | * Get a free request, queue_lock must be held. |
| 731 | * Returns NULL on failure, with queue_lock held. |
| 732 | * Returns !NULL on success, with queue_lock *not held*. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 734 | static struct request *get_request(struct request_queue *q, int rw_flags, |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 735 | struct bio *bio, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | { |
| 737 | struct request *rq = NULL; |
| 738 | struct request_list *rl = &q->rq; |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 739 | struct io_context *ioc = NULL; |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 740 | const int rw = rw_flags & 0x01; |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 741 | int may_queue, priv; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 743 | may_queue = elv_may_queue(q, rw_flags); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 744 | if (may_queue == ELV_MQUEUE_NO) |
| 745 | goto rq_starved; |
| 746 | |
| 747 | if (rl->count[rw]+1 >= queue_congestion_on_threshold(q)) { |
| 748 | if (rl->count[rw]+1 >= q->nr_requests) { |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 749 | ioc = current_io_context(GFP_ATOMIC, q->node); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 750 | /* |
| 751 | * The queue will fill after this allocation, so set |
| 752 | * it as full, and mark this process as "batching". |
| 753 | * This process will be allowed to complete a batch of |
| 754 | * requests, others will be blocked. |
| 755 | */ |
| 756 | if (!blk_queue_full(q, rw)) { |
| 757 | ioc_set_batching(q, ioc); |
| 758 | blk_set_queue_full(q, rw); |
| 759 | } else { |
| 760 | if (may_queue != ELV_MQUEUE_MUST |
| 761 | && !ioc_batching(q, ioc)) { |
| 762 | /* |
| 763 | * The queue is full and the allocating |
| 764 | * process is not a "batcher", and not |
| 765 | * exempted by the IO scheduler |
| 766 | */ |
| 767 | goto out; |
| 768 | } |
| 769 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 770 | } |
Thomas Maier | 79e2de4 | 2006-10-19 23:28:15 -0700 | [diff] [blame] | 771 | blk_set_queue_congested(q, rw); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 772 | } |
| 773 | |
Jens Axboe | 082cf69 | 2005-06-28 16:35:11 +0200 | [diff] [blame] | 774 | /* |
| 775 | * Only allow batching queuers to allocate up to 50% over the defined |
| 776 | * limit of requests, otherwise we could have thousands of requests |
| 777 | * allocated with any setting of ->nr_requests |
| 778 | */ |
Hugh Dickins | fd782a4 | 2005-06-29 15:15:40 +0100 | [diff] [blame] | 779 | if (rl->count[rw] >= (3 * q->nr_requests / 2)) |
Jens Axboe | 082cf69 | 2005-06-28 16:35:11 +0200 | [diff] [blame] | 780 | goto out; |
Hugh Dickins | fd782a4 | 2005-06-29 15:15:40 +0100 | [diff] [blame] | 781 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 782 | rl->count[rw]++; |
| 783 | rl->starved[rw] = 0; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 784 | |
Jens Axboe | 64521d1 | 2005-10-28 08:30:39 +0200 | [diff] [blame] | 785 | priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 786 | if (priv) |
| 787 | rl->elvpriv++; |
| 788 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 789 | spin_unlock_irq(q->queue_lock); |
| 790 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 791 | rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 792 | if (unlikely(!rq)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | /* |
| 794 | * Allocation failed presumably due to memory. Undo anything |
| 795 | * we might have messed up. |
| 796 | * |
| 797 | * Allocating task should really be put onto the front of the |
| 798 | * wait queue, but this is pretty rare. |
| 799 | */ |
| 800 | spin_lock_irq(q->queue_lock); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 801 | freed_request(q, rw, priv); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | |
| 803 | /* |
| 804 | * in the very unlikely event that allocation failed and no |
| 805 | * requests for this direction was pending, mark us starved |
| 806 | * so that freeing of a request in the other direction will |
| 807 | * notice us. another possible fix would be to split the |
| 808 | * rq mempool into READ and WRITE |
| 809 | */ |
| 810 | rq_starved: |
| 811 | if (unlikely(rl->count[rw] == 0)) |
| 812 | rl->starved[rw] = 1; |
| 813 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 814 | goto out; |
| 815 | } |
| 816 | |
Jens Axboe | 88ee5ef | 2005-11-12 11:09:12 +0100 | [diff] [blame] | 817 | /* |
| 818 | * ioc may be NULL here, and ioc_batching will be false. That's |
| 819 | * OK, if the queue is under the request limit then requests need |
| 820 | * not count toward the nr_batch_requests limit. There will always |
| 821 | * be some limit enforced by BLK_BATCH_TIME. |
| 822 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 823 | if (ioc_batching(q, ioc)) |
| 824 | ioc->nr_batch_requests--; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 825 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 826 | blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | return rq; |
| 829 | } |
| 830 | |
| 831 | /* |
| 832 | * No available requests for this queue, unplug the device and wait for some |
| 833 | * requests to become available. |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 834 | * |
| 835 | * Called with q->queue_lock held, and returns with it unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 836 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 837 | 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] | 838 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | { |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 840 | const int rw = rw_flags & 0x01; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 841 | struct request *rq; |
| 842 | |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 843 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 844 | while (!rq) { |
| 845 | DEFINE_WAIT(wait); |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 846 | struct io_context *ioc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | struct request_list *rl = &q->rq; |
| 848 | |
| 849 | prepare_to_wait_exclusive(&rl->wait[rw], &wait, |
| 850 | TASK_UNINTERRUPTIBLE); |
| 851 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 852 | blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 853 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 854 | __generic_unplug_device(q); |
| 855 | spin_unlock_irq(q->queue_lock); |
| 856 | io_schedule(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 858 | /* |
| 859 | * After sleeping, we become a "batching" process and |
| 860 | * will be able to allocate at least one request, and |
| 861 | * up to a big batch of them for a small period time. |
| 862 | * See ioc_batching, ioc_set_batching |
| 863 | */ |
| 864 | ioc = current_io_context(GFP_NOIO, q->node); |
| 865 | ioc_set_batching(q, ioc); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 866 | |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 867 | spin_lock_irq(q->queue_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 868 | finish_wait(&rl->wait[rw], &wait); |
Zhang, Yanmin | 05caf8d | 2008-05-22 15:13:29 +0200 | [diff] [blame] | 869 | |
| 870 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
| 871 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 872 | |
| 873 | return rq; |
| 874 | } |
| 875 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 876 | 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] | 877 | { |
| 878 | struct request *rq; |
| 879 | |
| 880 | BUG_ON(rw != READ && rw != WRITE); |
| 881 | |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 882 | spin_lock_irq(q->queue_lock); |
| 883 | if (gfp_mask & __GFP_WAIT) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 884 | rq = get_request_wait(q, rw, NULL); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 885 | } else { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 886 | rq = get_request(q, rw, NULL, gfp_mask); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 887 | if (!rq) |
| 888 | spin_unlock_irq(q->queue_lock); |
| 889 | } |
| 890 | /* q->queue_lock is unlocked at this point */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 891 | |
| 892 | return rq; |
| 893 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 894 | EXPORT_SYMBOL(blk_get_request); |
| 895 | |
| 896 | /** |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 897 | * blk_start_queueing - initiate dispatch of requests to device |
| 898 | * @q: request queue to kick into gear |
| 899 | * |
| 900 | * This is basically a helper to remove the need to know whether a queue |
| 901 | * is plugged or not if someone just wants to initiate dispatch of requests |
Jens Axboe | 80a4b58 | 2008-10-14 09:51:06 +0200 | [diff] [blame] | 902 | * for this queue. Should be used to start queueing on a device outside |
| 903 | * of ->request_fn() context. Also see @blk_run_queue. |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 904 | * |
| 905 | * The queue lock must be held with interrupts disabled. |
| 906 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 907 | void blk_start_queueing(struct request_queue *q) |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 908 | { |
Elias Oltmanns | 336c3d8 | 2008-10-01 16:02:33 +0200 | [diff] [blame] | 909 | if (!blk_queue_plugged(q)) { |
| 910 | if (unlikely(blk_queue_stopped(q))) |
| 911 | return; |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 912 | q->request_fn(q); |
Elias Oltmanns | 336c3d8 | 2008-10-01 16:02:33 +0200 | [diff] [blame] | 913 | } else |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 914 | __generic_unplug_device(q); |
| 915 | } |
| 916 | EXPORT_SYMBOL(blk_start_queueing); |
| 917 | |
| 918 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 919 | * blk_requeue_request - put a request back on queue |
| 920 | * @q: request queue where request should be inserted |
| 921 | * @rq: request to be inserted |
| 922 | * |
| 923 | * Description: |
| 924 | * Drivers often keep queueing requests until the hardware cannot accept |
| 925 | * more, when that condition happens we need to put the request back |
| 926 | * on the queue. Must be called with queue lock held. |
| 927 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 928 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 929 | { |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 930 | blk_delete_timer(rq); |
| 931 | blk_clear_rq_complete(rq); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 932 | blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); |
| 933 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 934 | if (blk_rq_tagged(rq)) |
| 935 | blk_queue_end_tag(q, rq); |
| 936 | |
| 937 | elv_requeue_request(q, rq); |
| 938 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | EXPORT_SYMBOL(blk_requeue_request); |
| 940 | |
| 941 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 942 | * blk_insert_request - insert a special request into a request queue |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | * @q: request queue where request should be inserted |
| 944 | * @rq: request to be inserted |
| 945 | * @at_head: insert request at head or tail of queue |
| 946 | * @data: private data |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | * |
| 948 | * Description: |
| 949 | * Many block devices need to execute commands asynchronously, so they don't |
| 950 | * block the whole kernel from preemption during request execution. This is |
| 951 | * accomplished normally by inserting aritficial requests tagged as |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 952 | * REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them |
| 953 | * be scheduled for actual execution by the request queue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 954 | * |
| 955 | * We have the option of inserting the head or the tail of the queue. |
| 956 | * Typically we use the tail for new ioctls and so forth. We use the head |
| 957 | * of the queue for things like a QUEUE_FULL message from a device, or a |
| 958 | * host that is unable to accept a particular command. |
| 959 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 960 | void blk_insert_request(struct request_queue *q, struct request *rq, |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 961 | int at_head, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | { |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 963 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 964 | unsigned long flags; |
| 965 | |
| 966 | /* |
| 967 | * tell I/O scheduler that this isn't a regular read/write (ie it |
| 968 | * must not attempt merges on this) and that it acts as a soft |
| 969 | * barrier |
| 970 | */ |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 971 | rq->cmd_type = REQ_TYPE_SPECIAL; |
| 972 | rq->cmd_flags |= REQ_SOFTBARRIER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 973 | |
| 974 | rq->special = data; |
| 975 | |
| 976 | spin_lock_irqsave(q->queue_lock, flags); |
| 977 | |
| 978 | /* |
| 979 | * If command is tagged, release the tag |
| 980 | */ |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 981 | if (blk_rq_tagged(rq)) |
| 982 | blk_queue_end_tag(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | |
Jerome Marchand | b238b3d | 2007-10-23 15:05:46 +0200 | [diff] [blame] | 984 | drive_stat_acct(rq, 1); |
Tejun Heo | 867d119 | 2005-04-24 02:06:05 -0500 | [diff] [blame] | 985 | __elv_add_request(q, rq, where, 0); |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 986 | blk_start_queueing(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 987 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 988 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 989 | EXPORT_SYMBOL(blk_insert_request); |
| 990 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 991 | /* |
| 992 | * add-request adds a request to the linked list. |
| 993 | * queue lock is held and interrupts disabled, as we muck with the |
| 994 | * request queue list. |
| 995 | */ |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 996 | static inline void add_request(struct request_queue *q, struct request *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 997 | { |
Jerome Marchand | b238b3d | 2007-10-23 15:05:46 +0200 | [diff] [blame] | 998 | drive_stat_acct(req, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1000 | /* |
| 1001 | * elevator indicated where it wants this request to be |
| 1002 | * inserted at elevator_merge time |
| 1003 | */ |
| 1004 | __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0); |
| 1005 | } |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1006 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1007 | static void part_round_stats_single(int cpu, struct hd_struct *part, |
| 1008 | unsigned long now) |
| 1009 | { |
| 1010 | if (now == part->stamp) |
| 1011 | return; |
| 1012 | |
| 1013 | if (part->in_flight) { |
| 1014 | __part_stat_add(cpu, part, time_in_queue, |
| 1015 | part->in_flight * (now - part->stamp)); |
| 1016 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
| 1017 | } |
| 1018 | part->stamp = now; |
| 1019 | } |
| 1020 | |
| 1021 | /** |
Randy Dunlap | 496aa8a | 2008-10-16 07:46:23 +0200 | [diff] [blame] | 1022 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
| 1023 | * @cpu: cpu number for stats access |
| 1024 | * @part: target partition |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1025 | * |
| 1026 | * The average IO queue length and utilisation statistics are maintained |
| 1027 | * by observing the current state of the queue length and the amount of |
| 1028 | * time it has been in this state for. |
| 1029 | * |
| 1030 | * Normally, that accounting is done on IO completion, but that can result |
| 1031 | * in more than a second's worth of IO being accounted for within any one |
| 1032 | * second, leading to >100% utilisation. To deal with that, we call this |
| 1033 | * function to do a round-off before returning the results when reading |
| 1034 | * /proc/diskstats. This accounts immediately for all queue usage up to |
| 1035 | * the current jiffies and restarts the counters again. |
| 1036 | */ |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1037 | void part_round_stats(int cpu, struct hd_struct *part) |
Jerome Marchand | 6f2576a | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1038 | { |
| 1039 | unsigned long now = jiffies; |
| 1040 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1041 | if (part->partno) |
| 1042 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); |
| 1043 | part_round_stats_single(cpu, part, now); |
Jerome Marchand | 6f2576a | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1044 | } |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1045 | EXPORT_SYMBOL_GPL(part_round_stats); |
Jerome Marchand | 6f2576a | 2008-02-08 11:04:35 +0100 | [diff] [blame] | 1046 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | /* |
| 1048 | * queue lock must be held |
| 1049 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1050 | void __blk_put_request(struct request_queue *q, struct request *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1052 | if (unlikely(!q)) |
| 1053 | return; |
| 1054 | if (unlikely(--req->ref_count)) |
| 1055 | return; |
| 1056 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 1057 | elv_completed_request(q, req); |
| 1058 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | /* |
| 1060 | * Request may not have originated from ll_rw_blk. if not, |
| 1061 | * it didn't come out of our reserved rq pools |
| 1062 | */ |
Jens Axboe | 49171e5 | 2006-08-10 08:59:11 +0200 | [diff] [blame] | 1063 | if (req->cmd_flags & REQ_ALLOCED) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1064 | int rw = rq_data_dir(req); |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1065 | int priv = req->cmd_flags & REQ_ELVPRIV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1067 | BUG_ON(!list_empty(&req->queuelist)); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 1068 | BUG_ON(!hlist_unhashed(&req->hash)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1069 | |
| 1070 | blk_free_request(q, req); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1071 | freed_request(q, rw, priv); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | } |
| 1073 | } |
Mike Christie | 6e39b69 | 2005-11-11 05:30:24 -0600 | [diff] [blame] | 1074 | EXPORT_SYMBOL_GPL(__blk_put_request); |
| 1075 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1076 | void blk_put_request(struct request *req) |
| 1077 | { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 1078 | unsigned long flags; |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1079 | struct request_queue *q = req->q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | |
FUJITA Tomonori | 52a93ba | 2008-07-15 21:21:45 +0200 | [diff] [blame] | 1081 | spin_lock_irqsave(q->queue_lock, flags); |
| 1082 | __blk_put_request(q, req); |
| 1083 | spin_unlock_irqrestore(q->queue_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1084 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1085 | EXPORT_SYMBOL(blk_put_request); |
| 1086 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 1087 | void init_request_from_bio(struct request *req, struct bio *bio) |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1088 | { |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 1089 | req->cpu = bio->bi_comp_cpu; |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1090 | req->cmd_type = REQ_TYPE_FS; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1091 | |
| 1092 | /* |
| 1093 | * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST) |
| 1094 | */ |
| 1095 | if (bio_rw_ahead(bio) || bio_failfast(bio)) |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1096 | req->cmd_flags |= REQ_FAILFAST; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1097 | |
| 1098 | /* |
| 1099 | * REQ_BARRIER implies no merging, but lets make it explicit |
| 1100 | */ |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1101 | if (unlikely(bio_discard(bio))) { |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1102 | req->cmd_flags |= REQ_DISCARD; |
| 1103 | if (bio_barrier(bio)) |
| 1104 | req->cmd_flags |= REQ_SOFTBARRIER; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1105 | req->q->prepare_discard_fn(req->q, req); |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1106 | } else if (unlikely(bio_barrier(bio))) |
| 1107 | req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1108 | |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 1109 | if (bio_sync(bio)) |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 1110 | req->cmd_flags |= REQ_RW_SYNC; |
Jens Axboe | 5404bc7 | 2006-08-10 09:01:02 +0200 | [diff] [blame] | 1111 | if (bio_rw_meta(bio)) |
| 1112 | req->cmd_flags |= REQ_RW_META; |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 1113 | |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1114 | req->errors = 0; |
| 1115 | req->hard_sector = req->sector = bio->bi_sector; |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1116 | req->ioprio = bio_prio(bio); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1117 | req->start_time = jiffies; |
NeilBrown | bc1c56f | 2007-08-16 13:31:30 +0200 | [diff] [blame] | 1118 | blk_rq_bio_prep(req->q, req, bio); |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1119 | } |
| 1120 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1121 | static int __make_request(struct request_queue *q, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1122 | { |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1123 | struct request *req; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1124 | int el_ret, nr_sectors, barrier, discard, err; |
Jens Axboe | 51da90f | 2006-07-18 04:14:45 +0200 | [diff] [blame] | 1125 | const unsigned short prio = bio_prio(bio); |
| 1126 | const int sync = bio_sync(bio); |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1127 | int rw_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | nr_sectors = bio_sectors(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | |
| 1131 | /* |
| 1132 | * low level driver can indicate that it wants pages above a |
| 1133 | * certain limit bounced to low memory (ie for highmem, or even |
| 1134 | * ISA dma in theory) |
| 1135 | */ |
| 1136 | blk_queue_bounce(q, &bio); |
| 1137 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | barrier = bio_barrier(bio); |
David Woodhouse | e17fc0a | 2008-08-09 16:42:20 +0100 | [diff] [blame] | 1139 | if (unlikely(barrier) && bio_has_data(bio) && |
| 1140 | (q->next_ordered == QUEUE_ORDERED_NONE)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1141 | err = -EOPNOTSUPP; |
| 1142 | goto end_io; |
| 1143 | } |
| 1144 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1145 | discard = bio_discard(bio); |
| 1146 | if (unlikely(discard) && !q->prepare_discard_fn) { |
| 1147 | err = -EOPNOTSUPP; |
| 1148 | goto end_io; |
| 1149 | } |
| 1150 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1151 | spin_lock_irq(q->queue_lock); |
| 1152 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1153 | if (unlikely(barrier) || elv_queue_empty(q)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | goto get_rq; |
| 1155 | |
| 1156 | el_ret = elv_merge(q, &req, bio); |
| 1157 | switch (el_ret) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1158 | case ELEVATOR_BACK_MERGE: |
| 1159 | BUG_ON(!rq_mergeable(req)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1160 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1161 | if (!ll_back_merge_fn(q, req, bio)) |
| 1162 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1163 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1164 | blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1165 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1166 | req->biotail->bi_next = bio; |
| 1167 | req->biotail = bio; |
| 1168 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
| 1169 | req->ioprio = ioprio_best(req->ioprio, prio); |
Jens Axboe | ab780f1 | 2008-08-26 10:25:02 +0200 | [diff] [blame] | 1170 | if (!blk_rq_cpu_valid(req)) |
| 1171 | req->cpu = bio->bi_comp_cpu; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1172 | drive_stat_acct(req, 0); |
| 1173 | if (!attempt_back_merge(q, req)) |
| 1174 | elv_merged_request(q, req, el_ret); |
| 1175 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1177 | case ELEVATOR_FRONT_MERGE: |
| 1178 | BUG_ON(!rq_mergeable(req)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1179 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1180 | if (!ll_front_merge_fn(q, req, bio)) |
| 1181 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1182 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1183 | blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1184 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1185 | bio->bi_next = req->bio; |
| 1186 | req->bio = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1187 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1188 | /* |
| 1189 | * may not be valid. if the low level driver said |
| 1190 | * it didn't need a bounce buffer then it better |
| 1191 | * not touch req->buffer either... |
| 1192 | */ |
| 1193 | req->buffer = bio_data(bio); |
| 1194 | req->current_nr_sectors = bio_cur_sectors(bio); |
| 1195 | req->hard_cur_sectors = req->current_nr_sectors; |
| 1196 | req->sector = req->hard_sector = bio->bi_sector; |
| 1197 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
| 1198 | req->ioprio = ioprio_best(req->ioprio, prio); |
Jens Axboe | ab780f1 | 2008-08-26 10:25:02 +0200 | [diff] [blame] | 1199 | if (!blk_rq_cpu_valid(req)) |
| 1200 | req->cpu = bio->bi_comp_cpu; |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1201 | drive_stat_acct(req, 0); |
| 1202 | if (!attempt_front_merge(q, req)) |
| 1203 | elv_merged_request(q, req, el_ret); |
| 1204 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1205 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1206 | /* ELV_NO_MERGE: elevator says don't/can't merge. */ |
| 1207 | default: |
| 1208 | ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1209 | } |
| 1210 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | get_rq: |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1212 | /* |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1213 | * This sync check and mask will be re-done in init_request_from_bio(), |
| 1214 | * but we need to set it earlier to expose the sync flag to the |
| 1215 | * rq allocator and io schedulers. |
| 1216 | */ |
| 1217 | rw_flags = bio_data_dir(bio); |
| 1218 | if (sync) |
| 1219 | rw_flags |= REQ_RW_SYNC; |
| 1220 | |
| 1221 | /* |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1222 | * Grab a free request. This is might sleep but can not fail. |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 1223 | * Returns with the queue unlocked. |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1224 | */ |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 1225 | req = get_request_wait(q, rw_flags, bio); |
Nick Piggin | d634453 | 2005-06-28 20:45:14 -0700 | [diff] [blame] | 1226 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1227 | /* |
| 1228 | * After dropping the lock and possibly sleeping here, our request |
| 1229 | * may now be mergeable after it had proven unmergeable (above). |
| 1230 | * We don't worry about that case for efficiency. It won't happen |
| 1231 | * often, and the elevators are able to handle it. |
| 1232 | */ |
Tejun Heo | 52d9e67 | 2006-01-06 09:49:58 +0100 | [diff] [blame] | 1233 | init_request_from_bio(req, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1234 | |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1235 | spin_lock_irq(q->queue_lock); |
Jens Axboe | c7c22e4 | 2008-09-13 20:26:01 +0200 | [diff] [blame] | 1236 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) || |
| 1237 | bio_flagged(bio, BIO_CPU_AFFINE)) |
| 1238 | req->cpu = blk_cpu_to_group(smp_processor_id()); |
Nick Piggin | 450991b | 2005-06-28 20:45:13 -0700 | [diff] [blame] | 1239 | if (elv_queue_empty(q)) |
| 1240 | blk_plug_device(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1241 | add_request(q, req); |
| 1242 | out: |
Jens Axboe | 4a534f9 | 2005-04-16 15:25:40 -0700 | [diff] [blame] | 1243 | if (sync) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1244 | __generic_unplug_device(q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1245 | spin_unlock_irq(q->queue_lock); |
| 1246 | return 0; |
| 1247 | |
| 1248 | end_io: |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 1249 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | return 0; |
| 1251 | } |
| 1252 | |
| 1253 | /* |
| 1254 | * If bio->bi_dev is a partition, remap the location |
| 1255 | */ |
| 1256 | static inline void blk_partition_remap(struct bio *bio) |
| 1257 | { |
| 1258 | struct block_device *bdev = bio->bi_bdev; |
| 1259 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1260 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1261 | struct hd_struct *p = bdev->bd_part; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1262 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | bio->bi_sector += p->start_sect; |
| 1264 | bio->bi_bdev = bdev->bd_contains; |
Alan D. Brunelle | c7149d6 | 2007-08-07 15:30:23 +0200 | [diff] [blame] | 1265 | |
| 1266 | blk_add_trace_remap(bdev_get_queue(bio->bi_bdev), bio, |
| 1267 | bdev->bd_dev, bio->bi_sector, |
| 1268 | bio->bi_sector - p->start_sect); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | } |
| 1270 | } |
| 1271 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1272 | static void handle_bad_sector(struct bio *bio) |
| 1273 | { |
| 1274 | char b[BDEVNAME_SIZE]; |
| 1275 | |
| 1276 | printk(KERN_INFO "attempt to access beyond end of device\n"); |
| 1277 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", |
| 1278 | bdevname(bio->bi_bdev, b), |
| 1279 | bio->bi_rw, |
| 1280 | (unsigned long long)bio->bi_sector + bio_sectors(bio), |
| 1281 | (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); |
| 1282 | |
| 1283 | set_bit(BIO_EOF, &bio->bi_flags); |
| 1284 | } |
| 1285 | |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1286 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
| 1287 | |
| 1288 | static DECLARE_FAULT_ATTR(fail_make_request); |
| 1289 | |
| 1290 | static int __init setup_fail_make_request(char *str) |
| 1291 | { |
| 1292 | return setup_fault_attr(&fail_make_request, str); |
| 1293 | } |
| 1294 | __setup("fail_make_request=", setup_fail_make_request); |
| 1295 | |
| 1296 | static int should_fail_request(struct bio *bio) |
| 1297 | { |
Tejun Heo | eddb2e2 | 2008-08-25 19:56:13 +0900 | [diff] [blame] | 1298 | struct hd_struct *part = bio->bi_bdev->bd_part; |
| 1299 | |
| 1300 | 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] | 1301 | return should_fail(&fail_make_request, bio->bi_size); |
| 1302 | |
| 1303 | return 0; |
| 1304 | } |
| 1305 | |
| 1306 | static int __init fail_make_request_debugfs(void) |
| 1307 | { |
| 1308 | return init_fault_attr_dentries(&fail_make_request, |
| 1309 | "fail_make_request"); |
| 1310 | } |
| 1311 | |
| 1312 | late_initcall(fail_make_request_debugfs); |
| 1313 | |
| 1314 | #else /* CONFIG_FAIL_MAKE_REQUEST */ |
| 1315 | |
| 1316 | static inline int should_fail_request(struct bio *bio) |
| 1317 | { |
| 1318 | return 0; |
| 1319 | } |
| 1320 | |
| 1321 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ |
| 1322 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1323 | /* |
| 1324 | * Check whether this bio extends beyond the end of the device. |
| 1325 | */ |
| 1326 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) |
| 1327 | { |
| 1328 | sector_t maxsector; |
| 1329 | |
| 1330 | if (!nr_sectors) |
| 1331 | return 0; |
| 1332 | |
| 1333 | /* Test device or partition size, when known. */ |
| 1334 | maxsector = bio->bi_bdev->bd_inode->i_size >> 9; |
| 1335 | if (maxsector) { |
| 1336 | sector_t sector = bio->bi_sector; |
| 1337 | |
| 1338 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { |
| 1339 | /* |
| 1340 | * This may well happen - the kernel calls bread() |
| 1341 | * without checking the size of the device, e.g., when |
| 1342 | * mounting a device. |
| 1343 | */ |
| 1344 | handle_bad_sector(bio); |
| 1345 | return 1; |
| 1346 | } |
| 1347 | } |
| 1348 | |
| 1349 | return 0; |
| 1350 | } |
| 1351 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1352 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1353 | * 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] | 1354 | * @bio: The bio describing the location in memory and on the device. |
| 1355 | * |
| 1356 | * generic_make_request() is used to make I/O requests of block |
| 1357 | * devices. It is passed a &struct bio, which describes the I/O that needs |
| 1358 | * to be done. |
| 1359 | * |
| 1360 | * generic_make_request() does not return any status. The |
| 1361 | * success/failure status of the request, along with notification of |
| 1362 | * completion, is delivered asynchronously through the bio->bi_end_io |
| 1363 | * function described (one day) else where. |
| 1364 | * |
| 1365 | * The caller of generic_make_request must make sure that bi_io_vec |
| 1366 | * are set to describe the memory buffer, and that bi_dev and bi_sector are |
| 1367 | * set to describe the device address, and the |
| 1368 | * bi_end_io and optionally bi_private are set to describe how |
| 1369 | * completion notification should be signaled. |
| 1370 | * |
| 1371 | * generic_make_request and the drivers it calls may use bi_next if this |
| 1372 | * bio happens to be merged with someone else, and may change bi_dev and |
| 1373 | * bi_sector for remaps as it sees fit. So the values of these fields |
| 1374 | * should NOT be depended on after the call to generic_make_request. |
| 1375 | */ |
Neil Brown | d89d879 | 2007-05-01 09:53:42 +0200 | [diff] [blame] | 1376 | static inline void __generic_make_request(struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1377 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1378 | struct request_queue *q; |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1379 | sector_t old_sector; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1380 | int ret, nr_sectors = bio_sectors(bio); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1381 | dev_t old_dev; |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1382 | int err = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | |
| 1384 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1385 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1386 | if (bio_check_eod(bio, nr_sectors)) |
| 1387 | goto end_io; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1388 | |
| 1389 | /* |
| 1390 | * Resolve the mapping until finished. (drivers are |
| 1391 | * still free to implement/resolve their own stacking |
| 1392 | * by explicitly returning 0) |
| 1393 | * |
| 1394 | * NOTE: we don't repeat the blk_size check for each new device. |
| 1395 | * Stacking drivers are expected to know what they are doing. |
| 1396 | */ |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1397 | old_sector = -1; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1398 | old_dev = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1399 | do { |
| 1400 | char b[BDEVNAME_SIZE]; |
| 1401 | |
| 1402 | q = bdev_get_queue(bio->bi_bdev); |
| 1403 | if (!q) { |
| 1404 | printk(KERN_ERR |
| 1405 | "generic_make_request: Trying to access " |
| 1406 | "nonexistent block-device %s (%Lu)\n", |
| 1407 | bdevname(bio->bi_bdev, b), |
| 1408 | (long long) bio->bi_sector); |
| 1409 | end_io: |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1410 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1411 | break; |
| 1412 | } |
| 1413 | |
Jens Axboe | 4fa253f | 2007-07-18 13:13:10 +0200 | [diff] [blame] | 1414 | if (unlikely(nr_sectors > q->max_hw_sectors)) { |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1415 | printk(KERN_ERR "bio too big device %s (%u > %u)\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1416 | bdevname(bio->bi_bdev, b), |
| 1417 | bio_sectors(bio), |
| 1418 | q->max_hw_sectors); |
| 1419 | goto end_io; |
| 1420 | } |
| 1421 | |
Nick Piggin | fde6ad2 | 2005-06-23 00:08:53 -0700 | [diff] [blame] | 1422 | if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1423 | goto end_io; |
| 1424 | |
Akinobu Mita | c17bb49 | 2006-12-08 02:39:46 -0800 | [diff] [blame] | 1425 | if (should_fail_request(bio)) |
| 1426 | goto end_io; |
| 1427 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1428 | /* |
| 1429 | * If this device has partitions, remap block n |
| 1430 | * of partition p to block n+start(p) of the disk. |
| 1431 | */ |
| 1432 | blk_partition_remap(bio); |
| 1433 | |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 1434 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) |
| 1435 | goto end_io; |
| 1436 | |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1437 | if (old_sector != -1) |
Jens Axboe | 4fa253f | 2007-07-18 13:13:10 +0200 | [diff] [blame] | 1438 | blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1439 | old_sector); |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1440 | |
| 1441 | blk_add_trace_bio(q, bio, BLK_TA_QUEUE); |
| 1442 | |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1443 | old_sector = bio->bi_sector; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1444 | old_dev = bio->bi_bdev->bd_dev; |
| 1445 | |
Jens Axboe | c07e2b4 | 2007-07-18 13:27:58 +0200 | [diff] [blame] | 1446 | if (bio_check_eod(bio, nr_sectors)) |
| 1447 | goto end_io; |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 1448 | if ((bio_empty_barrier(bio) && !q->prepare_flush_fn) || |
| 1449 | (bio_discard(bio) && !q->prepare_discard_fn)) { |
Jens Axboe | 51fd77b | 2007-11-02 08:49:08 +0100 | [diff] [blame] | 1450 | err = -EOPNOTSUPP; |
| 1451 | goto end_io; |
| 1452 | } |
NeilBrown | 5ddfe96 | 2006-10-30 22:07:21 -0800 | [diff] [blame] | 1453 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1454 | ret = q->make_request_fn(q, bio); |
| 1455 | } while (ret); |
| 1456 | } |
| 1457 | |
Neil Brown | d89d879 | 2007-05-01 09:53:42 +0200 | [diff] [blame] | 1458 | /* |
| 1459 | * We only want one ->make_request_fn to be active at a time, |
| 1460 | * else stack usage with stacked devices could be a problem. |
| 1461 | * So use current->bio_{list,tail} to keep a list of requests |
| 1462 | * submited by a make_request_fn function. |
| 1463 | * current->bio_tail is also used as a flag to say if |
| 1464 | * generic_make_request is currently active in this task or not. |
| 1465 | * If it is NULL, then no make_request is active. If it is non-NULL, |
| 1466 | * then a make_request is active, and new requests should be added |
| 1467 | * at the tail |
| 1468 | */ |
| 1469 | void generic_make_request(struct bio *bio) |
| 1470 | { |
| 1471 | if (current->bio_tail) { |
| 1472 | /* make_request is active */ |
| 1473 | *(current->bio_tail) = bio; |
| 1474 | bio->bi_next = NULL; |
| 1475 | current->bio_tail = &bio->bi_next; |
| 1476 | return; |
| 1477 | } |
| 1478 | /* following loop may be a bit non-obvious, and so deserves some |
| 1479 | * explanation. |
| 1480 | * Before entering the loop, bio->bi_next is NULL (as all callers |
| 1481 | * ensure that) so we have a list with a single bio. |
| 1482 | * We pretend that we have just taken it off a longer list, so |
| 1483 | * we assign bio_list to the next (which is NULL) and bio_tail |
| 1484 | * to &bio_list, thus initialising the bio_list of new bios to be |
| 1485 | * added. __generic_make_request may indeed add some more bios |
| 1486 | * through a recursive call to generic_make_request. If it |
| 1487 | * did, we find a non-NULL value in bio_list and re-enter the loop |
| 1488 | * from the top. In this case we really did just take the bio |
| 1489 | * of the top of the list (no pretending) and so fixup bio_list and |
| 1490 | * bio_tail or bi_next, and call into __generic_make_request again. |
| 1491 | * |
| 1492 | * The loop was structured like this to make only one call to |
| 1493 | * __generic_make_request (which is important as it is large and |
| 1494 | * inlined) and to keep the structure simple. |
| 1495 | */ |
| 1496 | BUG_ON(bio->bi_next); |
| 1497 | do { |
| 1498 | current->bio_list = bio->bi_next; |
| 1499 | if (bio->bi_next == NULL) |
| 1500 | current->bio_tail = ¤t->bio_list; |
| 1501 | else |
| 1502 | bio->bi_next = NULL; |
| 1503 | __generic_make_request(bio); |
| 1504 | bio = current->bio_list; |
| 1505 | } while (bio); |
| 1506 | current->bio_tail = NULL; /* deactivate */ |
| 1507 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1508 | EXPORT_SYMBOL(generic_make_request); |
| 1509 | |
| 1510 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1511 | * 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] | 1512 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
| 1513 | * @bio: The &struct bio which describes the I/O |
| 1514 | * |
| 1515 | * submit_bio() is very similar in purpose to generic_make_request(), and |
| 1516 | * 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] | 1517 | * interfaces; @bio must be presetup and ready for I/O. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1518 | * |
| 1519 | */ |
| 1520 | void submit_bio(int rw, struct bio *bio) |
| 1521 | { |
| 1522 | int count = bio_sectors(bio); |
| 1523 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1524 | bio->bi_rw |= rw; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1525 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1526 | /* |
| 1527 | * If it's a regular read/write or a barrier with data attached, |
| 1528 | * go through the normal accounting stuff before submission. |
| 1529 | */ |
Jens Axboe | a9c701e | 2008-08-08 11:04:44 +0200 | [diff] [blame] | 1530 | if (bio_has_data(bio)) { |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1531 | if (rw & WRITE) { |
| 1532 | count_vm_events(PGPGOUT, count); |
| 1533 | } else { |
| 1534 | task_io_account_read(bio->bi_size); |
| 1535 | count_vm_events(PGPGIN, count); |
| 1536 | } |
| 1537 | |
| 1538 | if (unlikely(block_dump)) { |
| 1539 | char b[BDEVNAME_SIZE]; |
| 1540 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1541 | current->comm, task_pid_nr(current), |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1542 | (rw & WRITE) ? "WRITE" : "READ", |
| 1543 | (unsigned long long)bio->bi_sector, |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1544 | bdevname(bio->bi_bdev, b)); |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1545 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1546 | } |
| 1547 | |
| 1548 | generic_make_request(bio); |
| 1549 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1550 | EXPORT_SYMBOL(submit_bio); |
| 1551 | |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1552 | /** |
Kiyoshi Ueda | 82124d6 | 2008-09-18 10:45:38 -0400 | [diff] [blame] | 1553 | * blk_rq_check_limits - Helper function to check a request for the queue limit |
| 1554 | * @q: the queue |
| 1555 | * @rq: the request being checked |
| 1556 | * |
| 1557 | * Description: |
| 1558 | * @rq may have been made based on weaker limitations of upper-level queues |
| 1559 | * in request stacking drivers, and it may violate the limitation of @q. |
| 1560 | * Since the block layer and the underlying device driver trust @rq |
| 1561 | * after it is inserted to @q, it should be checked against @q before |
| 1562 | * the insertion using this generic function. |
| 1563 | * |
| 1564 | * This function should also be useful for request stacking drivers |
| 1565 | * in some cases below, so export this fuction. |
| 1566 | * Request stacking drivers like request-based dm may change the queue |
| 1567 | * limits while requests are in the queue (e.g. dm's table swapping). |
| 1568 | * Such request stacking drivers should check those requests agaist |
| 1569 | * the new queue limits again when they dispatch those requests, |
| 1570 | * although such checkings are also done against the old queue limits |
| 1571 | * when submitting requests. |
| 1572 | */ |
| 1573 | int blk_rq_check_limits(struct request_queue *q, struct request *rq) |
| 1574 | { |
| 1575 | if (rq->nr_sectors > q->max_sectors || |
| 1576 | rq->data_len > q->max_hw_sectors << 9) { |
| 1577 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
| 1578 | return -EIO; |
| 1579 | } |
| 1580 | |
| 1581 | /* |
| 1582 | * queue's settings related to segment counting like q->bounce_pfn |
| 1583 | * may differ from that of other stacking queues. |
| 1584 | * Recalculate it to check the request correctly on this queue's |
| 1585 | * limitation. |
| 1586 | */ |
| 1587 | blk_recalc_rq_segments(rq); |
| 1588 | if (rq->nr_phys_segments > q->max_phys_segments || |
| 1589 | rq->nr_phys_segments > q->max_hw_segments) { |
| 1590 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
| 1591 | return -EIO; |
| 1592 | } |
| 1593 | |
| 1594 | return 0; |
| 1595 | } |
| 1596 | EXPORT_SYMBOL_GPL(blk_rq_check_limits); |
| 1597 | |
| 1598 | /** |
| 1599 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request |
| 1600 | * @q: the queue to submit the request |
| 1601 | * @rq: the request being queued |
| 1602 | */ |
| 1603 | int blk_insert_cloned_request(struct request_queue *q, struct request *rq) |
| 1604 | { |
| 1605 | unsigned long flags; |
| 1606 | |
| 1607 | if (blk_rq_check_limits(q, rq)) |
| 1608 | return -EIO; |
| 1609 | |
| 1610 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
| 1611 | if (rq->rq_disk && rq->rq_disk->part0.make_it_fail && |
| 1612 | should_fail(&fail_make_request, blk_rq_bytes(rq))) |
| 1613 | return -EIO; |
| 1614 | #endif |
| 1615 | |
| 1616 | spin_lock_irqsave(q->queue_lock, flags); |
| 1617 | |
| 1618 | /* |
| 1619 | * Submitting request must be dequeued before calling this function |
| 1620 | * because it will be linked to another request_queue |
| 1621 | */ |
| 1622 | BUG_ON(blk_queued_rq(rq)); |
| 1623 | |
| 1624 | drive_stat_acct(rq, 1); |
| 1625 | __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); |
| 1626 | |
| 1627 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1628 | |
| 1629 | return 0; |
| 1630 | } |
| 1631 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); |
| 1632 | |
| 1633 | /** |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1634 | * __end_that_request_first - end I/O on a request |
| 1635 | * @req: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1636 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1637 | * @nr_bytes: number of bytes to complete |
| 1638 | * |
| 1639 | * Description: |
| 1640 | * Ends I/O on a number of bytes attached to @req, and sets it up |
| 1641 | * for the next range of segments (if any) in the cluster. |
| 1642 | * |
| 1643 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1644 | * %0 - we are done with this request, call end_that_request_last() |
| 1645 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | 3bcddea | 2007-12-11 17:52:28 -0500 | [diff] [blame] | 1646 | **/ |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1647 | static int __end_that_request_first(struct request *req, int error, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1648 | int nr_bytes) |
| 1649 | { |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1650 | int total_bytes, bio_nbytes, next_idx = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1651 | struct bio *bio; |
| 1652 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 1653 | blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE); |
| 1654 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1655 | /* |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1656 | * 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] | 1657 | * sense key with us all the way through |
| 1658 | */ |
| 1659 | if (!blk_pc_request(req)) |
| 1660 | req->errors = 0; |
| 1661 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1662 | if (error && (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))) { |
| 1663 | 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] | 1664 | req->rq_disk ? req->rq_disk->disk_name : "?", |
| 1665 | (unsigned long long)req->sector); |
| 1666 | } |
| 1667 | |
Jens Axboe | d72d904 | 2005-11-01 08:35:42 +0100 | [diff] [blame] | 1668 | if (blk_fs_request(req) && req->rq_disk) { |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1669 | const int rw = rq_data_dir(req); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1670 | struct hd_struct *part; |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1671 | int cpu; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1672 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1673 | cpu = part_stat_lock(); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1674 | part = disk_map_sector_rcu(req->rq_disk, req->sector); |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1675 | part_stat_add(cpu, part, sectors[rw], nr_bytes >> 9); |
| 1676 | part_stat_unlock(); |
Jens Axboe | d72d904 | 2005-11-01 08:35:42 +0100 | [diff] [blame] | 1677 | } |
| 1678 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1679 | total_bytes = bio_nbytes = 0; |
| 1680 | while ((bio = req->bio) != NULL) { |
| 1681 | int nbytes; |
| 1682 | |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 1683 | /* |
| 1684 | * For an empty barrier request, the low level driver must |
| 1685 | * store a potential error location in ->sector. We pass |
| 1686 | * that back up in ->bi_sector. |
| 1687 | */ |
| 1688 | if (blk_empty_barrier(req)) |
| 1689 | bio->bi_sector = req->sector; |
| 1690 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1691 | if (nr_bytes >= bio->bi_size) { |
| 1692 | req->bio = bio->bi_next; |
| 1693 | nbytes = bio->bi_size; |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 1694 | req_bio_endio(req, bio, nbytes, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1695 | next_idx = 0; |
| 1696 | bio_nbytes = 0; |
| 1697 | } else { |
| 1698 | int idx = bio->bi_idx + next_idx; |
| 1699 | |
| 1700 | if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { |
| 1701 | blk_dump_rq_flags(req, "__end_that"); |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1702 | printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n", |
Harvey Harrison | 24c03d4 | 2008-05-01 04:35:17 -0700 | [diff] [blame] | 1703 | __func__, bio->bi_idx, bio->bi_vcnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1704 | break; |
| 1705 | } |
| 1706 | |
| 1707 | nbytes = bio_iovec_idx(bio, idx)->bv_len; |
| 1708 | BIO_BUG_ON(nbytes > bio->bi_size); |
| 1709 | |
| 1710 | /* |
| 1711 | * not a complete bvec done |
| 1712 | */ |
| 1713 | if (unlikely(nbytes > nr_bytes)) { |
| 1714 | bio_nbytes += nr_bytes; |
| 1715 | total_bytes += nr_bytes; |
| 1716 | break; |
| 1717 | } |
| 1718 | |
| 1719 | /* |
| 1720 | * advance to the next vector |
| 1721 | */ |
| 1722 | next_idx++; |
| 1723 | bio_nbytes += nbytes; |
| 1724 | } |
| 1725 | |
| 1726 | total_bytes += nbytes; |
| 1727 | nr_bytes -= nbytes; |
| 1728 | |
Jens Axboe | 6728cb0 | 2008-01-31 13:03:55 +0100 | [diff] [blame] | 1729 | bio = req->bio; |
| 1730 | if (bio) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1731 | /* |
| 1732 | * end more in this run, or just return 'not-done' |
| 1733 | */ |
| 1734 | if (unlikely(nr_bytes <= 0)) |
| 1735 | break; |
| 1736 | } |
| 1737 | } |
| 1738 | |
| 1739 | /* |
| 1740 | * completely done |
| 1741 | */ |
| 1742 | if (!req->bio) |
| 1743 | return 0; |
| 1744 | |
| 1745 | /* |
| 1746 | * if the request wasn't completed, update state |
| 1747 | */ |
| 1748 | if (bio_nbytes) { |
NeilBrown | 5bb23a6 | 2007-09-27 12:46:13 +0200 | [diff] [blame] | 1749 | req_bio_endio(req, bio, bio_nbytes, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1750 | bio->bi_idx += next_idx; |
| 1751 | bio_iovec(bio)->bv_offset += nr_bytes; |
| 1752 | bio_iovec(bio)->bv_len -= nr_bytes; |
| 1753 | } |
| 1754 | |
| 1755 | blk_recalc_rq_sectors(req, total_bytes >> 9); |
| 1756 | blk_recalc_rq_segments(req); |
| 1757 | return 1; |
| 1758 | } |
| 1759 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1760 | /* |
| 1761 | * queue lock must be held |
| 1762 | */ |
Kiyoshi Ueda | 5450d3e | 2007-12-11 17:53:03 -0500 | [diff] [blame] | 1763 | static void end_that_request_last(struct request *req, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1764 | { |
| 1765 | struct gendisk *disk = req->rq_disk; |
Tejun Heo | 8ffdc65 | 2006-01-06 09:49:03 +0100 | [diff] [blame] | 1766 | |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 1767 | blk_delete_timer(req); |
| 1768 | |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1769 | if (blk_rq_tagged(req)) |
| 1770 | blk_queue_end_tag(req->q, req); |
| 1771 | |
| 1772 | if (blk_queued_rq(req)) |
| 1773 | blkdev_dequeue_request(req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1774 | |
| 1775 | if (unlikely(laptop_mode) && blk_fs_request(req)) |
| 1776 | laptop_io_completion(); |
| 1777 | |
Jens Axboe | fd0ff8a | 2006-05-23 11:23:49 +0200 | [diff] [blame] | 1778 | /* |
| 1779 | * Account IO completion. bar_rq isn't accounted as a normal |
| 1780 | * IO on queueing nor completion. Accounting the containing |
| 1781 | * request is enough. |
| 1782 | */ |
| 1783 | if (disk && blk_fs_request(req) && req != &req->q->bar_rq) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1784 | unsigned long duration = jiffies - req->start_time; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1785 | const int rw = rq_data_dir(req); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1786 | struct hd_struct *part; |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 1787 | int cpu; |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1788 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1789 | cpu = part_stat_lock(); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1790 | part = disk_map_sector_rcu(disk, req->sector); |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 1791 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1792 | part_stat_inc(cpu, part, ios[rw]); |
| 1793 | part_stat_add(cpu, part, ticks[rw], duration); |
| 1794 | part_round_stats(cpu, part); |
| 1795 | part_dec_in_flight(part); |
Tejun Heo | e71bf0d | 2008-09-03 09:03:02 +0200 | [diff] [blame] | 1796 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 1797 | part_stat_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1798 | } |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1799 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1800 | if (req->end_io) |
Tejun Heo | 8ffdc65 | 2006-01-06 09:49:03 +0100 | [diff] [blame] | 1801 | req->end_io(req, error); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1802 | else { |
| 1803 | if (blk_bidi_rq(req)) |
| 1804 | __blk_put_request(req->next_rq->q, req->next_rq); |
| 1805 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1806 | __blk_put_request(req->q, req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1807 | } |
| 1808 | } |
| 1809 | |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1810 | /** |
| 1811 | * blk_rq_bytes - Returns bytes left to complete in the entire request |
Randy Dunlap | 5d87a05 | 2008-02-20 09:01:22 +0100 | [diff] [blame] | 1812 | * @rq: the request being processed |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1813 | **/ |
| 1814 | unsigned int blk_rq_bytes(struct request *rq) |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1815 | { |
| 1816 | if (blk_fs_request(rq)) |
| 1817 | return rq->hard_nr_sectors << 9; |
| 1818 | |
| 1819 | return rq->data_len; |
| 1820 | } |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1821 | EXPORT_SYMBOL_GPL(blk_rq_bytes); |
| 1822 | |
| 1823 | /** |
| 1824 | * 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] | 1825 | * @rq: the request being processed |
Kiyoshi Ueda | 3b11313 | 2007-12-11 17:41:17 -0500 | [diff] [blame] | 1826 | **/ |
| 1827 | unsigned int blk_rq_cur_bytes(struct request *rq) |
| 1828 | { |
| 1829 | if (blk_fs_request(rq)) |
| 1830 | return rq->current_nr_sectors << 9; |
| 1831 | |
| 1832 | if (rq->bio) |
| 1833 | return rq->bio->bi_size; |
| 1834 | |
| 1835 | return rq->data_len; |
| 1836 | } |
| 1837 | EXPORT_SYMBOL_GPL(blk_rq_cur_bytes); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1838 | |
| 1839 | /** |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1840 | * end_request - end I/O on the current segment of the request |
Randy Dunlap | 8f731f7 | 2007-10-18 23:39:28 -0700 | [diff] [blame] | 1841 | * @req: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1842 | * @uptodate: error value or %0/%1 uptodate flag |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1843 | * |
| 1844 | * Description: |
| 1845 | * Ends I/O on the current segment of a request. If that is the only |
| 1846 | * remaining segment, the request is also completed and freed. |
| 1847 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1848 | * This is a remnant of how older block drivers handled I/O completions. |
| 1849 | * 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] | 1850 | * they have a residual value to account for. For that case this function |
| 1851 | * isn't really useful, unless the residual just happens to be the |
| 1852 | * full current segment. In other words, don't use this function in new |
Kiyoshi Ueda | d00e29f | 2008-10-01 10:14:46 -0400 | [diff] [blame] | 1853 | * code. Use blk_end_request() or __blk_end_request() to end a request. |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1854 | **/ |
| 1855 | void end_request(struct request *req, int uptodate) |
| 1856 | { |
Kiyoshi Ueda | d00e29f | 2008-10-01 10:14:46 -0400 | [diff] [blame] | 1857 | int error = 0; |
| 1858 | |
| 1859 | if (uptodate <= 0) |
| 1860 | error = uptodate ? uptodate : -EIO; |
| 1861 | |
| 1862 | __blk_end_request(req, error, req->hard_cur_sectors << 9); |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 1863 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1864 | EXPORT_SYMBOL(end_request); |
| 1865 | |
Kiyoshi Ueda | 32fab44 | 2008-09-18 10:45:09 -0400 | [diff] [blame] | 1866 | static int end_that_request_data(struct request *rq, int error, |
| 1867 | unsigned int nr_bytes, unsigned int bidi_bytes) |
| 1868 | { |
| 1869 | if (rq->bio) { |
| 1870 | if (__end_that_request_first(rq, error, nr_bytes)) |
| 1871 | return 1; |
| 1872 | |
| 1873 | /* Bidi request must be completed as a whole */ |
| 1874 | if (blk_bidi_rq(rq) && |
| 1875 | __end_that_request_first(rq->next_rq, error, bidi_bytes)) |
| 1876 | return 1; |
| 1877 | } |
| 1878 | |
| 1879 | return 0; |
| 1880 | } |
| 1881 | |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1882 | /** |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1883 | * blk_end_io - Generic end_io function to complete a request. |
| 1884 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1885 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1886 | * @nr_bytes: number of bytes to complete @rq |
| 1887 | * @bidi_bytes: number of bytes to complete @rq->next_rq |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1888 | * @drv_callback: function called between completion of bios in the request |
| 1889 | * and completion of the request. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1890 | * If the callback returns non %0, this helper returns without |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1891 | * completion of the request. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1892 | * |
| 1893 | * Description: |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1894 | * 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] | 1895 | * If @rq has leftover, sets it up for the next range of segments. |
| 1896 | * |
| 1897 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1898 | * %0 - we are done with this request |
| 1899 | * %1 - this request is not freed yet, it still has pending buffers. |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1900 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1901 | static int blk_end_io(struct request *rq, int error, unsigned int nr_bytes, |
| 1902 | unsigned int bidi_bytes, |
| 1903 | int (drv_callback)(struct request *)) |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1904 | { |
| 1905 | struct request_queue *q = rq->q; |
| 1906 | unsigned long flags = 0UL; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1907 | |
Kiyoshi Ueda | 32fab44 | 2008-09-18 10:45:09 -0400 | [diff] [blame] | 1908 | if (end_that_request_data(rq, error, nr_bytes, bidi_bytes)) |
| 1909 | return 1; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1910 | |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1911 | /* Special feature for tricky drivers */ |
| 1912 | if (drv_callback && drv_callback(rq)) |
| 1913 | return 1; |
| 1914 | |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1915 | add_disk_randomness(rq->rq_disk); |
| 1916 | |
| 1917 | spin_lock_irqsave(q->queue_lock, flags); |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1918 | end_that_request_last(rq, error); |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1919 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1920 | |
| 1921 | return 0; |
| 1922 | } |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1923 | |
| 1924 | /** |
| 1925 | * blk_end_request - Helper function for drivers to complete the request. |
| 1926 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1927 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1928 | * @nr_bytes: number of bytes to complete |
| 1929 | * |
| 1930 | * Description: |
| 1931 | * Ends I/O on a number of bytes attached to @rq. |
| 1932 | * If @rq has leftover, sets it up for the next range of segments. |
| 1933 | * |
| 1934 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1935 | * %0 - we are done with this request |
| 1936 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1937 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1938 | 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] | 1939 | { |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1940 | return blk_end_io(rq, error, nr_bytes, 0, NULL); |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1941 | } |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1942 | EXPORT_SYMBOL_GPL(blk_end_request); |
| 1943 | |
| 1944 | /** |
| 1945 | * __blk_end_request - Helper function for drivers to complete the request. |
| 1946 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1947 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1948 | * @nr_bytes: number of bytes to complete |
| 1949 | * |
| 1950 | * Description: |
| 1951 | * Must be called with queue lock held unlike blk_end_request(). |
| 1952 | * |
| 1953 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1954 | * %0 - we are done with this request |
| 1955 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1956 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1957 | int __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1958 | { |
Jens Axboe | 6054016 | 2008-08-26 13:34:34 +0200 | [diff] [blame] | 1959 | if (rq->bio && __end_that_request_first(rq, error, nr_bytes)) |
Jens Axboe | 051cc39 | 2008-08-08 11:06:45 +0200 | [diff] [blame] | 1960 | return 1; |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1961 | |
| 1962 | add_disk_randomness(rq->rq_disk); |
| 1963 | |
Kiyoshi Ueda | b828623 | 2007-12-11 17:53:24 -0500 | [diff] [blame] | 1964 | end_that_request_last(rq, error); |
Kiyoshi Ueda | 336cdb4 | 2007-12-11 17:40:30 -0500 | [diff] [blame] | 1965 | |
| 1966 | return 0; |
| 1967 | } |
| 1968 | EXPORT_SYMBOL_GPL(__blk_end_request); |
| 1969 | |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 1970 | /** |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1971 | * blk_end_bidi_request - Helper function for drivers to complete bidi request. |
| 1972 | * @rq: the bidi request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1973 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1974 | * @nr_bytes: number of bytes to complete @rq |
| 1975 | * @bidi_bytes: number of bytes to complete @rq->next_rq |
| 1976 | * |
| 1977 | * Description: |
| 1978 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
| 1979 | * |
| 1980 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 1981 | * %0 - we are done with this request |
| 1982 | * %1 - still buffers pending for this request |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1983 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 1984 | int blk_end_bidi_request(struct request *rq, int error, unsigned int nr_bytes, |
| 1985 | unsigned int bidi_bytes) |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 1986 | { |
| 1987 | return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL); |
| 1988 | } |
| 1989 | EXPORT_SYMBOL_GPL(blk_end_bidi_request); |
| 1990 | |
| 1991 | /** |
Kiyoshi Ueda | 32fab44 | 2008-09-18 10:45:09 -0400 | [diff] [blame] | 1992 | * blk_update_request - Special helper function for request stacking drivers |
| 1993 | * @rq: the request being processed |
| 1994 | * @error: %0 for success, < %0 for error |
| 1995 | * @nr_bytes: number of bytes to complete @rq |
| 1996 | * |
| 1997 | * Description: |
| 1998 | * Ends I/O on a number of bytes attached to @rq, but doesn't complete |
| 1999 | * the request structure even if @rq doesn't have leftover. |
| 2000 | * If @rq has leftover, sets it up for the next range of segments. |
| 2001 | * |
| 2002 | * This special helper function is only for request stacking drivers |
| 2003 | * (e.g. request-based dm) so that they can handle partial completion. |
| 2004 | * Actual device drivers should use blk_end_request instead. |
| 2005 | */ |
| 2006 | void blk_update_request(struct request *rq, int error, unsigned int nr_bytes) |
| 2007 | { |
| 2008 | if (!end_that_request_data(rq, error, nr_bytes, 0)) { |
| 2009 | /* |
| 2010 | * These members are not updated in end_that_request_data() |
| 2011 | * when all bios are completed. |
| 2012 | * Update them so that the request stacking driver can find |
| 2013 | * how many bytes remain in the request later. |
| 2014 | */ |
| 2015 | rq->nr_sectors = rq->hard_nr_sectors = 0; |
| 2016 | rq->current_nr_sectors = rq->hard_cur_sectors = 0; |
| 2017 | } |
| 2018 | } |
| 2019 | EXPORT_SYMBOL_GPL(blk_update_request); |
| 2020 | |
| 2021 | /** |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2022 | * blk_end_request_callback - Special helper function for tricky drivers |
| 2023 | * @rq: the request being processed |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2024 | * @error: %0 for success, < %0 for error |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2025 | * @nr_bytes: number of bytes to complete |
| 2026 | * @drv_callback: function called between completion of bios in the request |
| 2027 | * and completion of the request. |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2028 | * If the callback returns non %0, this helper returns without |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2029 | * completion of the request. |
| 2030 | * |
| 2031 | * Description: |
| 2032 | * Ends I/O on a number of bytes attached to @rq. |
| 2033 | * If @rq has leftover, sets it up for the next range of segments. |
| 2034 | * |
| 2035 | * This special helper function is used only for existing tricky drivers. |
| 2036 | * (e.g. cdrom_newpc_intr() of ide-cd) |
| 2037 | * This interface will be removed when such drivers are rewritten. |
| 2038 | * Don't use this interface in other places anymore. |
| 2039 | * |
| 2040 | * Return: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 2041 | * %0 - we are done with this request |
| 2042 | * %1 - this request is not freed yet. |
| 2043 | * this request still has pending buffers or |
| 2044 | * the driver doesn't want to finish this request yet. |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2045 | **/ |
Jens Axboe | 22b1321 | 2008-01-31 12:36:19 +0100 | [diff] [blame] | 2046 | int blk_end_request_callback(struct request *rq, int error, |
| 2047 | unsigned int nr_bytes, |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2048 | int (drv_callback)(struct request *)) |
| 2049 | { |
Kiyoshi Ueda | e3a04fe | 2007-12-11 17:51:46 -0500 | [diff] [blame] | 2050 | return blk_end_io(rq, error, nr_bytes, 0, drv_callback); |
Kiyoshi Ueda | e19a3ab | 2007-12-11 17:51:02 -0500 | [diff] [blame] | 2051 | } |
| 2052 | EXPORT_SYMBOL_GPL(blk_end_request_callback); |
| 2053 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 2054 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
| 2055 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2056 | { |
David Woodhouse | d628eae | 2008-08-09 16:22:17 +0100 | [diff] [blame] | 2057 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw, and |
| 2058 | 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] | 2059 | rq->cmd_flags |= (bio->bi_rw & 3); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2060 | |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 2061 | if (bio_has_data(bio)) { |
| 2062 | rq->nr_phys_segments = bio_phys_segments(q, bio); |
David Woodhouse | fb2dce8 | 2008-08-05 18:01:53 +0100 | [diff] [blame] | 2063 | rq->buffer = bio_data(bio); |
| 2064 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2065 | rq->current_nr_sectors = bio_cur_sectors(bio); |
| 2066 | rq->hard_cur_sectors = rq->current_nr_sectors; |
| 2067 | rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); |
Mike Christie | 0e75f90 | 2006-12-01 10:40:55 +0100 | [diff] [blame] | 2068 | rq->data_len = bio->bi_size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | |
| 2070 | rq->bio = rq->biotail = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2071 | |
NeilBrown | 6684657 | 2007-08-16 13:31:28 +0200 | [diff] [blame] | 2072 | if (bio->bi_bdev) |
| 2073 | rq->rq_disk = bio->bi_bdev->bd_disk; |
| 2074 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2075 | |
Kiyoshi Ueda | ef9e3fa | 2008-10-01 16:12:15 +0200 | [diff] [blame] | 2076 | /** |
| 2077 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy |
| 2078 | * @q : the queue of the device being checked |
| 2079 | * |
| 2080 | * Description: |
| 2081 | * Check if underlying low-level drivers of a device are busy. |
| 2082 | * If the drivers want to export their busy state, they must set own |
| 2083 | * exporting function using blk_queue_lld_busy() first. |
| 2084 | * |
| 2085 | * Basically, this function is used only by request stacking drivers |
| 2086 | * to stop dispatching requests to underlying devices when underlying |
| 2087 | * devices are busy. This behavior helps more I/O merging on the queue |
| 2088 | * of the request stacking driver and prevents I/O throughput regression |
| 2089 | * on burst I/O load. |
| 2090 | * |
| 2091 | * Return: |
| 2092 | * 0 - Not busy (The request stacking driver should dispatch request) |
| 2093 | * 1 - Busy (The request stacking driver should stop dispatching request) |
| 2094 | */ |
| 2095 | int blk_lld_busy(struct request_queue *q) |
| 2096 | { |
| 2097 | if (q->lld_busy_fn) |
| 2098 | return q->lld_busy_fn(q); |
| 2099 | |
| 2100 | return 0; |
| 2101 | } |
| 2102 | EXPORT_SYMBOL_GPL(blk_lld_busy); |
| 2103 | |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame] | 2104 | int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2105 | { |
| 2106 | return queue_work(kblockd_workqueue, work); |
| 2107 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2108 | EXPORT_SYMBOL(kblockd_schedule_work); |
| 2109 | |
Andrew Morton | 19a75d8 | 2007-05-09 02:33:56 -0700 | [diff] [blame] | 2110 | void kblockd_flush_work(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2111 | { |
Oleg Nesterov | 28e53bd | 2007-05-09 02:34:22 -0700 | [diff] [blame] | 2112 | cancel_work_sync(work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2113 | } |
Andrew Morton | 19a75d8 | 2007-05-09 02:33:56 -0700 | [diff] [blame] | 2114 | EXPORT_SYMBOL(kblockd_flush_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2115 | |
| 2116 | int __init blk_dev_init(void) |
| 2117 | { |
| 2118 | kblockd_workqueue = create_workqueue("kblockd"); |
| 2119 | if (!kblockd_workqueue) |
| 2120 | panic("Failed to create kblockd\n"); |
| 2121 | |
| 2122 | request_cachep = kmem_cache_create("blkdev_requests", |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 2123 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2124 | |
Jens Axboe | 8324aa9 | 2008-01-29 14:51:59 +0100 | [diff] [blame] | 2125 | blk_requestq_cachep = kmem_cache_create("blkdev_queue", |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2126 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2127 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2128 | return 0; |
| 2129 | } |
| 2130 | |