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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
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> | |
6728cb0e JA |
6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
7 | * - July2000 | |
1da177e4 LT |
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 | */ | |
1da177e4 LT |
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> | |
1da177e4 LT |
24 | #include <linux/completion.h> |
25 | #include <linux/slab.h> | |
26 | #include <linux/swap.h> | |
27 | #include <linux/writeback.h> | |
faccbd4b | 28 | #include <linux/task_io_accounting_ops.h> |
c17bb495 | 29 | #include <linux/fault-inject.h> |
55782138 LZ |
30 | |
31 | #define CREATE_TRACE_POINTS | |
32 | #include <trace/events/block.h> | |
1da177e4 | 33 | |
8324aa91 JA |
34 | #include "blk.h" |
35 | ||
0bfc2455 | 36 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap); |
b0da3f0d | 37 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
55782138 | 38 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
0bfc2455 | 39 | |
165125e1 | 40 | static int __make_request(struct request_queue *q, struct bio *bio); |
1da177e4 LT |
41 | |
42 | /* | |
43 | * For the allocated request tables | |
44 | */ | |
5ece6c52 | 45 | static struct kmem_cache *request_cachep; |
1da177e4 LT |
46 | |
47 | /* | |
48 | * For queue allocation | |
49 | */ | |
6728cb0e | 50 | struct kmem_cache *blk_requestq_cachep; |
1da177e4 | 51 | |
1da177e4 LT |
52 | /* |
53 | * Controlling structure to kblockd | |
54 | */ | |
ff856bad | 55 | static struct workqueue_struct *kblockd_workqueue; |
1da177e4 | 56 | |
26b8256e JA |
57 | static void drive_stat_acct(struct request *rq, int new_io) |
58 | { | |
28f13702 | 59 | struct hd_struct *part; |
26b8256e | 60 | int rw = rq_data_dir(rq); |
c9959059 | 61 | int cpu; |
26b8256e | 62 | |
c2553b58 | 63 | if (!blk_do_io_stat(rq)) |
26b8256e JA |
64 | return; |
65 | ||
074a7aca | 66 | cpu = part_stat_lock(); |
c9959059 | 67 | |
7681bfee YI |
68 | if (!new_io) { |
69 | part = rq->part; | |
074a7aca | 70 | part_stat_inc(cpu, part, merges[rw]); |
7681bfee YI |
71 | } else { |
72 | part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); | |
074a7aca | 73 | part_round_stats(cpu, part); |
316d315b | 74 | part_inc_in_flight(part, rw); |
7681bfee | 75 | rq->part = part; |
26b8256e | 76 | } |
e71bf0d0 | 77 | |
074a7aca | 78 | part_stat_unlock(); |
26b8256e JA |
79 | } |
80 | ||
8324aa91 | 81 | void blk_queue_congestion_threshold(struct request_queue *q) |
1da177e4 LT |
82 | { |
83 | int nr; | |
84 | ||
85 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
86 | if (nr > q->nr_requests) | |
87 | nr = q->nr_requests; | |
88 | q->nr_congestion_on = nr; | |
89 | ||
90 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
91 | if (nr < 1) | |
92 | nr = 1; | |
93 | q->nr_congestion_off = nr; | |
94 | } | |
95 | ||
1da177e4 LT |
96 | /** |
97 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info | |
98 | * @bdev: device | |
99 | * | |
100 | * Locates the passed device's request queue and returns the address of its | |
101 | * backing_dev_info | |
102 | * | |
103 | * Will return NULL if the request queue cannot be located. | |
104 | */ | |
105 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) | |
106 | { | |
107 | struct backing_dev_info *ret = NULL; | |
165125e1 | 108 | struct request_queue *q = bdev_get_queue(bdev); |
1da177e4 LT |
109 | |
110 | if (q) | |
111 | ret = &q->backing_dev_info; | |
112 | return ret; | |
113 | } | |
1da177e4 LT |
114 | EXPORT_SYMBOL(blk_get_backing_dev_info); |
115 | ||
2a4aa30c | 116 | void blk_rq_init(struct request_queue *q, struct request *rq) |
1da177e4 | 117 | { |
1afb20f3 FT |
118 | memset(rq, 0, sizeof(*rq)); |
119 | ||
1da177e4 | 120 | INIT_LIST_HEAD(&rq->queuelist); |
242f9dcb | 121 | INIT_LIST_HEAD(&rq->timeout_list); |
c7c22e4d | 122 | rq->cpu = -1; |
63a71386 | 123 | rq->q = q; |
a2dec7b3 | 124 | rq->__sector = (sector_t) -1; |
2e662b65 JA |
125 | INIT_HLIST_NODE(&rq->hash); |
126 | RB_CLEAR_NODE(&rq->rb_node); | |
d7e3c324 | 127 | rq->cmd = rq->__cmd; |
e2494e1b | 128 | rq->cmd_len = BLK_MAX_CDB; |
63a71386 | 129 | rq->tag = -1; |
1da177e4 | 130 | rq->ref_count = 1; |
b243ddcb | 131 | rq->start_time = jiffies; |
9195291e | 132 | set_start_time_ns(rq); |
7681bfee | 133 | rq->part = NULL; |
1da177e4 | 134 | } |
2a4aa30c | 135 | EXPORT_SYMBOL(blk_rq_init); |
1da177e4 | 136 | |
5bb23a68 N |
137 | static void req_bio_endio(struct request *rq, struct bio *bio, |
138 | unsigned int nbytes, int error) | |
1da177e4 | 139 | { |
165125e1 | 140 | struct request_queue *q = rq->q; |
797e7dbb | 141 | |
dd4c133f | 142 | if (&q->flush_rq != rq) { |
5bb23a68 N |
143 | if (error) |
144 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
145 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
146 | error = -EIO; | |
797e7dbb | 147 | |
5bb23a68 | 148 | if (unlikely(nbytes > bio->bi_size)) { |
6728cb0e | 149 | printk(KERN_ERR "%s: want %u bytes done, %u left\n", |
24c03d47 | 150 | __func__, nbytes, bio->bi_size); |
5bb23a68 N |
151 | nbytes = bio->bi_size; |
152 | } | |
797e7dbb | 153 | |
08bafc03 KM |
154 | if (unlikely(rq->cmd_flags & REQ_QUIET)) |
155 | set_bit(BIO_QUIET, &bio->bi_flags); | |
156 | ||
5bb23a68 N |
157 | bio->bi_size -= nbytes; |
158 | bio->bi_sector += (nbytes >> 9); | |
7ba1ba12 MP |
159 | |
160 | if (bio_integrity(bio)) | |
161 | bio_integrity_advance(bio, nbytes); | |
162 | ||
5bb23a68 | 163 | if (bio->bi_size == 0) |
6712ecf8 | 164 | bio_endio(bio, error); |
5bb23a68 | 165 | } else { |
5bb23a68 | 166 | /* |
dd4c133f TH |
167 | * Okay, this is the sequenced flush request in |
168 | * progress, just record the error; | |
5bb23a68 | 169 | */ |
dd4c133f TH |
170 | if (error && !q->flush_err) |
171 | q->flush_err = error; | |
5bb23a68 | 172 | } |
1da177e4 | 173 | } |
1da177e4 | 174 | |
1da177e4 LT |
175 | void blk_dump_rq_flags(struct request *rq, char *msg) |
176 | { | |
177 | int bit; | |
178 | ||
6728cb0e | 179 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%x\n", msg, |
4aff5e23 JA |
180 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, |
181 | rq->cmd_flags); | |
1da177e4 | 182 | |
83096ebf TH |
183 | printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", |
184 | (unsigned long long)blk_rq_pos(rq), | |
185 | blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); | |
731ec497 | 186 | printk(KERN_INFO " bio %p, biotail %p, buffer %p, len %u\n", |
2e46e8b2 | 187 | rq->bio, rq->biotail, rq->buffer, blk_rq_bytes(rq)); |
1da177e4 | 188 | |
33659ebb | 189 | if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { |
6728cb0e | 190 | printk(KERN_INFO " cdb: "); |
d34c87e4 | 191 | for (bit = 0; bit < BLK_MAX_CDB; bit++) |
1da177e4 LT |
192 | printk("%02x ", rq->cmd[bit]); |
193 | printk("\n"); | |
194 | } | |
195 | } | |
1da177e4 LT |
196 | EXPORT_SYMBOL(blk_dump_rq_flags); |
197 | ||
1da177e4 LT |
198 | /* |
199 | * "plug" the device if there are no outstanding requests: this will | |
200 | * force the transfer to start only after we have put all the requests | |
201 | * on the list. | |
202 | * | |
203 | * This is called with interrupts off and no requests on the queue and | |
204 | * with the queue lock held. | |
205 | */ | |
165125e1 | 206 | void blk_plug_device(struct request_queue *q) |
1da177e4 LT |
207 | { |
208 | WARN_ON(!irqs_disabled()); | |
209 | ||
210 | /* | |
211 | * don't plug a stopped queue, it must be paired with blk_start_queue() | |
212 | * which will restart the queueing | |
213 | */ | |
7daac490 | 214 | if (blk_queue_stopped(q)) |
1da177e4 LT |
215 | return; |
216 | ||
e48ec690 | 217 | if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) { |
1da177e4 | 218 | mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); |
5f3ea37c | 219 | trace_block_plug(q); |
2056a782 | 220 | } |
1da177e4 | 221 | } |
1da177e4 LT |
222 | EXPORT_SYMBOL(blk_plug_device); |
223 | ||
6c5e0c4d JA |
224 | /** |
225 | * blk_plug_device_unlocked - plug a device without queue lock held | |
226 | * @q: The &struct request_queue to plug | |
227 | * | |
228 | * Description: | |
229 | * Like @blk_plug_device(), but grabs the queue lock and disables | |
230 | * interrupts. | |
231 | **/ | |
232 | void blk_plug_device_unlocked(struct request_queue *q) | |
233 | { | |
234 | unsigned long flags; | |
235 | ||
236 | spin_lock_irqsave(q->queue_lock, flags); | |
237 | blk_plug_device(q); | |
238 | spin_unlock_irqrestore(q->queue_lock, flags); | |
239 | } | |
240 | EXPORT_SYMBOL(blk_plug_device_unlocked); | |
241 | ||
1da177e4 LT |
242 | /* |
243 | * remove the queue from the plugged list, if present. called with | |
244 | * queue lock held and interrupts disabled. | |
245 | */ | |
165125e1 | 246 | int blk_remove_plug(struct request_queue *q) |
1da177e4 LT |
247 | { |
248 | WARN_ON(!irqs_disabled()); | |
249 | ||
e48ec690 | 250 | if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q)) |
1da177e4 LT |
251 | return 0; |
252 | ||
253 | del_timer(&q->unplug_timer); | |
254 | return 1; | |
255 | } | |
1da177e4 LT |
256 | EXPORT_SYMBOL(blk_remove_plug); |
257 | ||
258 | /* | |
259 | * remove the plug and let it rip.. | |
260 | */ | |
165125e1 | 261 | void __generic_unplug_device(struct request_queue *q) |
1da177e4 | 262 | { |
7daac490 | 263 | if (unlikely(blk_queue_stopped(q))) |
1da177e4 | 264 | return; |
a31a9738 | 265 | if (!blk_remove_plug(q) && !blk_queue_nonrot(q)) |
1da177e4 LT |
266 | return; |
267 | ||
22e2c507 | 268 | q->request_fn(q); |
1da177e4 | 269 | } |
1da177e4 LT |
270 | |
271 | /** | |
272 | * generic_unplug_device - fire a request queue | |
165125e1 | 273 | * @q: The &struct request_queue in question |
1da177e4 LT |
274 | * |
275 | * Description: | |
276 | * Linux uses plugging to build bigger requests queues before letting | |
277 | * the device have at them. If a queue is plugged, the I/O scheduler | |
278 | * is still adding and merging requests on the queue. Once the queue | |
279 | * gets unplugged, the request_fn defined for the queue is invoked and | |
280 | * transfers started. | |
281 | **/ | |
165125e1 | 282 | void generic_unplug_device(struct request_queue *q) |
1da177e4 | 283 | { |
dbaf2c00 JA |
284 | if (blk_queue_plugged(q)) { |
285 | spin_lock_irq(q->queue_lock); | |
286 | __generic_unplug_device(q); | |
287 | spin_unlock_irq(q->queue_lock); | |
288 | } | |
1da177e4 LT |
289 | } |
290 | EXPORT_SYMBOL(generic_unplug_device); | |
291 | ||
292 | static void blk_backing_dev_unplug(struct backing_dev_info *bdi, | |
293 | struct page *page) | |
294 | { | |
165125e1 | 295 | struct request_queue *q = bdi->unplug_io_data; |
1da177e4 | 296 | |
2ad8b1ef | 297 | blk_unplug(q); |
1da177e4 LT |
298 | } |
299 | ||
86db1e29 | 300 | void blk_unplug_work(struct work_struct *work) |
1da177e4 | 301 | { |
165125e1 JA |
302 | struct request_queue *q = |
303 | container_of(work, struct request_queue, unplug_work); | |
1da177e4 | 304 | |
5f3ea37c | 305 | trace_block_unplug_io(q); |
1da177e4 LT |
306 | q->unplug_fn(q); |
307 | } | |
308 | ||
86db1e29 | 309 | void blk_unplug_timeout(unsigned long data) |
1da177e4 | 310 | { |
165125e1 | 311 | struct request_queue *q = (struct request_queue *)data; |
1da177e4 | 312 | |
5f3ea37c | 313 | trace_block_unplug_timer(q); |
18887ad9 | 314 | kblockd_schedule_work(q, &q->unplug_work); |
1da177e4 LT |
315 | } |
316 | ||
2ad8b1ef AB |
317 | void blk_unplug(struct request_queue *q) |
318 | { | |
319 | /* | |
320 | * devices don't necessarily have an ->unplug_fn defined | |
321 | */ | |
322 | if (q->unplug_fn) { | |
5f3ea37c | 323 | trace_block_unplug_io(q); |
2ad8b1ef AB |
324 | q->unplug_fn(q); |
325 | } | |
326 | } | |
327 | EXPORT_SYMBOL(blk_unplug); | |
328 | ||
1da177e4 LT |
329 | /** |
330 | * blk_start_queue - restart a previously stopped queue | |
165125e1 | 331 | * @q: The &struct request_queue in question |
1da177e4 LT |
332 | * |
333 | * Description: | |
334 | * blk_start_queue() will clear the stop flag on the queue, and call | |
335 | * the request_fn for the queue if it was in a stopped state when | |
336 | * entered. Also see blk_stop_queue(). Queue lock must be held. | |
337 | **/ | |
165125e1 | 338 | void blk_start_queue(struct request_queue *q) |
1da177e4 | 339 | { |
a038e253 PBG |
340 | WARN_ON(!irqs_disabled()); |
341 | ||
75ad23bc | 342 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
a538cd03 | 343 | __blk_run_queue(q); |
1da177e4 | 344 | } |
1da177e4 LT |
345 | EXPORT_SYMBOL(blk_start_queue); |
346 | ||
347 | /** | |
348 | * blk_stop_queue - stop a queue | |
165125e1 | 349 | * @q: The &struct request_queue in question |
1da177e4 LT |
350 | * |
351 | * Description: | |
352 | * The Linux block layer assumes that a block driver will consume all | |
353 | * entries on the request queue when the request_fn strategy is called. | |
354 | * Often this will not happen, because of hardware limitations (queue | |
355 | * depth settings). If a device driver gets a 'queue full' response, | |
356 | * or if it simply chooses not to queue more I/O at one point, it can | |
357 | * call this function to prevent the request_fn from being called until | |
358 | * the driver has signalled it's ready to go again. This happens by calling | |
359 | * blk_start_queue() to restart queue operations. Queue lock must be held. | |
360 | **/ | |
165125e1 | 361 | void blk_stop_queue(struct request_queue *q) |
1da177e4 LT |
362 | { |
363 | blk_remove_plug(q); | |
75ad23bc | 364 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
1da177e4 LT |
365 | } |
366 | EXPORT_SYMBOL(blk_stop_queue); | |
367 | ||
368 | /** | |
369 | * blk_sync_queue - cancel any pending callbacks on a queue | |
370 | * @q: the queue | |
371 | * | |
372 | * Description: | |
373 | * The block layer may perform asynchronous callback activity | |
374 | * on a queue, such as calling the unplug function after a timeout. | |
375 | * A block device may call blk_sync_queue to ensure that any | |
376 | * such activity is cancelled, thus allowing it to release resources | |
59c51591 | 377 | * that the callbacks might use. The caller must already have made sure |
1da177e4 LT |
378 | * that its ->make_request_fn will not re-add plugging prior to calling |
379 | * this function. | |
380 | * | |
381 | */ | |
382 | void blk_sync_queue(struct request_queue *q) | |
383 | { | |
384 | del_timer_sync(&q->unplug_timer); | |
70ed28b9 | 385 | del_timer_sync(&q->timeout); |
64d01dc9 | 386 | cancel_work_sync(&q->unplug_work); |
e43473b7 | 387 | throtl_shutdown_timer_wq(q); |
1da177e4 LT |
388 | } |
389 | EXPORT_SYMBOL(blk_sync_queue); | |
390 | ||
391 | /** | |
80a4b58e | 392 | * __blk_run_queue - run a single device queue |
1da177e4 | 393 | * @q: The queue to run |
80a4b58e JA |
394 | * |
395 | * Description: | |
396 | * See @blk_run_queue. This variant must be called with the queue lock | |
397 | * held and interrupts disabled. | |
398 | * | |
1da177e4 | 399 | */ |
75ad23bc | 400 | void __blk_run_queue(struct request_queue *q) |
1da177e4 | 401 | { |
1da177e4 | 402 | blk_remove_plug(q); |
dac07ec1 | 403 | |
a538cd03 TH |
404 | if (unlikely(blk_queue_stopped(q))) |
405 | return; | |
406 | ||
407 | if (elv_queue_empty(q)) | |
408 | return; | |
409 | ||
dac07ec1 JA |
410 | /* |
411 | * Only recurse once to avoid overrunning the stack, let the unplug | |
412 | * handling reinvoke the handler shortly if we already got there. | |
413 | */ | |
a538cd03 TH |
414 | if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { |
415 | q->request_fn(q); | |
416 | queue_flag_clear(QUEUE_FLAG_REENTER, q); | |
417 | } else { | |
418 | queue_flag_set(QUEUE_FLAG_PLUGGED, q); | |
419 | kblockd_schedule_work(q, &q->unplug_work); | |
420 | } | |
75ad23bc NP |
421 | } |
422 | EXPORT_SYMBOL(__blk_run_queue); | |
dac07ec1 | 423 | |
75ad23bc NP |
424 | /** |
425 | * blk_run_queue - run a single device queue | |
426 | * @q: The queue to run | |
80a4b58e JA |
427 | * |
428 | * Description: | |
429 | * Invoke request handling on this queue, if it has pending work to do. | |
a7f55792 | 430 | * May be used to restart queueing when a request has completed. |
75ad23bc NP |
431 | */ |
432 | void blk_run_queue(struct request_queue *q) | |
433 | { | |
434 | unsigned long flags; | |
435 | ||
436 | spin_lock_irqsave(q->queue_lock, flags); | |
437 | __blk_run_queue(q); | |
1da177e4 LT |
438 | spin_unlock_irqrestore(q->queue_lock, flags); |
439 | } | |
440 | EXPORT_SYMBOL(blk_run_queue); | |
441 | ||
165125e1 | 442 | void blk_put_queue(struct request_queue *q) |
483f4afc AV |
443 | { |
444 | kobject_put(&q->kobj); | |
445 | } | |
483f4afc | 446 | |
6728cb0e | 447 | void blk_cleanup_queue(struct request_queue *q) |
483f4afc | 448 | { |
e3335de9 JA |
449 | /* |
450 | * We know we have process context here, so we can be a little | |
451 | * cautious and ensure that pending block actions on this device | |
452 | * are done before moving on. Going into this function, we should | |
453 | * not have processes doing IO to this device. | |
454 | */ | |
455 | blk_sync_queue(q); | |
456 | ||
31373d09 | 457 | del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); |
483f4afc | 458 | mutex_lock(&q->sysfs_lock); |
75ad23bc | 459 | queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q); |
483f4afc AV |
460 | mutex_unlock(&q->sysfs_lock); |
461 | ||
462 | if (q->elevator) | |
463 | elevator_exit(q->elevator); | |
464 | ||
465 | blk_put_queue(q); | |
466 | } | |
1da177e4 LT |
467 | EXPORT_SYMBOL(blk_cleanup_queue); |
468 | ||
165125e1 | 469 | static int blk_init_free_list(struct request_queue *q) |
1da177e4 LT |
470 | { |
471 | struct request_list *rl = &q->rq; | |
472 | ||
1abec4fd MS |
473 | if (unlikely(rl->rq_pool)) |
474 | return 0; | |
475 | ||
1faa16d2 JA |
476 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
477 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; | |
cb98fc8b | 478 | rl->elvpriv = 0; |
1faa16d2 JA |
479 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
480 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); | |
1da177e4 | 481 | |
1946089a CL |
482 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
483 | mempool_free_slab, request_cachep, q->node); | |
1da177e4 LT |
484 | |
485 | if (!rl->rq_pool) | |
486 | return -ENOMEM; | |
487 | ||
488 | return 0; | |
489 | } | |
490 | ||
165125e1 | 491 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
1da177e4 | 492 | { |
1946089a CL |
493 | return blk_alloc_queue_node(gfp_mask, -1); |
494 | } | |
495 | EXPORT_SYMBOL(blk_alloc_queue); | |
1da177e4 | 496 | |
165125e1 | 497 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
1946089a | 498 | { |
165125e1 | 499 | struct request_queue *q; |
e0bf68dd | 500 | int err; |
1946089a | 501 | |
8324aa91 | 502 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
94f6030c | 503 | gfp_mask | __GFP_ZERO, node_id); |
1da177e4 LT |
504 | if (!q) |
505 | return NULL; | |
506 | ||
e0bf68dd PZ |
507 | q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; |
508 | q->backing_dev_info.unplug_io_data = q; | |
0989a025 JA |
509 | q->backing_dev_info.ra_pages = |
510 | (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
511 | q->backing_dev_info.state = 0; | |
512 | q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; | |
d993831f | 513 | q->backing_dev_info.name = "block"; |
0989a025 | 514 | |
e0bf68dd PZ |
515 | err = bdi_init(&q->backing_dev_info); |
516 | if (err) { | |
8324aa91 | 517 | kmem_cache_free(blk_requestq_cachep, q); |
e0bf68dd PZ |
518 | return NULL; |
519 | } | |
520 | ||
e43473b7 VG |
521 | if (blk_throtl_init(q)) { |
522 | kmem_cache_free(blk_requestq_cachep, q); | |
523 | return NULL; | |
524 | } | |
525 | ||
31373d09 MG |
526 | setup_timer(&q->backing_dev_info.laptop_mode_wb_timer, |
527 | laptop_mode_timer_fn, (unsigned long) q); | |
1da177e4 | 528 | init_timer(&q->unplug_timer); |
242f9dcb JA |
529 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); |
530 | INIT_LIST_HEAD(&q->timeout_list); | |
dd4c133f | 531 | INIT_LIST_HEAD(&q->pending_flushes); |
713ada9b | 532 | INIT_WORK(&q->unplug_work, blk_unplug_work); |
483f4afc | 533 | |
8324aa91 | 534 | kobject_init(&q->kobj, &blk_queue_ktype); |
1da177e4 | 535 | |
483f4afc | 536 | mutex_init(&q->sysfs_lock); |
e7e72bf6 | 537 | spin_lock_init(&q->__queue_lock); |
483f4afc | 538 | |
1da177e4 LT |
539 | return q; |
540 | } | |
1946089a | 541 | EXPORT_SYMBOL(blk_alloc_queue_node); |
1da177e4 LT |
542 | |
543 | /** | |
544 | * blk_init_queue - prepare a request queue for use with a block device | |
545 | * @rfn: The function to be called to process requests that have been | |
546 | * placed on the queue. | |
547 | * @lock: Request queue spin lock | |
548 | * | |
549 | * Description: | |
550 | * If a block device wishes to use the standard request handling procedures, | |
551 | * which sorts requests and coalesces adjacent requests, then it must | |
552 | * call blk_init_queue(). The function @rfn will be called when there | |
553 | * are requests on the queue that need to be processed. If the device | |
554 | * supports plugging, then @rfn may not be called immediately when requests | |
555 | * are available on the queue, but may be called at some time later instead. | |
556 | * Plugged queues are generally unplugged when a buffer belonging to one | |
557 | * of the requests on the queue is needed, or due to memory pressure. | |
558 | * | |
559 | * @rfn is not required, or even expected, to remove all requests off the | |
560 | * queue, but only as many as it can handle at a time. If it does leave | |
561 | * requests on the queue, it is responsible for arranging that the requests | |
562 | * get dealt with eventually. | |
563 | * | |
564 | * The queue spin lock must be held while manipulating the requests on the | |
a038e253 PBG |
565 | * request queue; this lock will be taken also from interrupt context, so irq |
566 | * disabling is needed for it. | |
1da177e4 | 567 | * |
710027a4 | 568 | * Function returns a pointer to the initialized request queue, or %NULL if |
1da177e4 LT |
569 | * it didn't succeed. |
570 | * | |
571 | * Note: | |
572 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
573 | * when the block device is deactivated (such as at module unload). | |
574 | **/ | |
1946089a | 575 | |
165125e1 | 576 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
1da177e4 | 577 | { |
1946089a CL |
578 | return blk_init_queue_node(rfn, lock, -1); |
579 | } | |
580 | EXPORT_SYMBOL(blk_init_queue); | |
581 | ||
165125e1 | 582 | struct request_queue * |
1946089a CL |
583 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
584 | { | |
c86d1b8a | 585 | struct request_queue *uninit_q, *q; |
1da177e4 | 586 | |
c86d1b8a MS |
587 | uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
588 | if (!uninit_q) | |
589 | return NULL; | |
590 | ||
591 | q = blk_init_allocated_queue_node(uninit_q, rfn, lock, node_id); | |
592 | if (!q) | |
593 | blk_cleanup_queue(uninit_q); | |
594 | ||
595 | return q; | |
01effb0d MS |
596 | } |
597 | EXPORT_SYMBOL(blk_init_queue_node); | |
598 | ||
599 | struct request_queue * | |
600 | blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, | |
601 | spinlock_t *lock) | |
602 | { | |
603 | return blk_init_allocated_queue_node(q, rfn, lock, -1); | |
604 | } | |
605 | EXPORT_SYMBOL(blk_init_allocated_queue); | |
606 | ||
607 | struct request_queue * | |
608 | blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn, | |
609 | spinlock_t *lock, int node_id) | |
610 | { | |
1da177e4 LT |
611 | if (!q) |
612 | return NULL; | |
613 | ||
1946089a | 614 | q->node = node_id; |
c86d1b8a | 615 | if (blk_init_free_list(q)) |
8669aafd | 616 | return NULL; |
1da177e4 LT |
617 | |
618 | q->request_fn = rfn; | |
1da177e4 | 619 | q->prep_rq_fn = NULL; |
28018c24 | 620 | q->unprep_rq_fn = NULL; |
1da177e4 | 621 | q->unplug_fn = generic_unplug_device; |
bc58ba94 | 622 | q->queue_flags = QUEUE_FLAG_DEFAULT; |
1da177e4 LT |
623 | q->queue_lock = lock; |
624 | ||
f3b144aa JA |
625 | /* |
626 | * This also sets hw/phys segments, boundary and size | |
627 | */ | |
1da177e4 | 628 | blk_queue_make_request(q, __make_request); |
1da177e4 | 629 | |
44ec9542 AS |
630 | q->sg_reserved_size = INT_MAX; |
631 | ||
1da177e4 LT |
632 | /* |
633 | * all done | |
634 | */ | |
635 | if (!elevator_init(q, NULL)) { | |
636 | blk_queue_congestion_threshold(q); | |
637 | return q; | |
638 | } | |
639 | ||
1da177e4 LT |
640 | return NULL; |
641 | } | |
01effb0d | 642 | EXPORT_SYMBOL(blk_init_allocated_queue_node); |
1da177e4 | 643 | |
165125e1 | 644 | int blk_get_queue(struct request_queue *q) |
1da177e4 | 645 | { |
fde6ad22 | 646 | if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { |
483f4afc | 647 | kobject_get(&q->kobj); |
1da177e4 LT |
648 | return 0; |
649 | } | |
650 | ||
651 | return 1; | |
652 | } | |
1da177e4 | 653 | |
165125e1 | 654 | static inline void blk_free_request(struct request_queue *q, struct request *rq) |
1da177e4 | 655 | { |
4aff5e23 | 656 | if (rq->cmd_flags & REQ_ELVPRIV) |
cb98fc8b | 657 | elv_put_request(q, rq); |
1da177e4 LT |
658 | mempool_free(rq, q->rq.rq_pool); |
659 | } | |
660 | ||
1ea25ecb | 661 | static struct request * |
42dad764 | 662 | blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask) |
1da177e4 LT |
663 | { |
664 | struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); | |
665 | ||
666 | if (!rq) | |
667 | return NULL; | |
668 | ||
2a4aa30c | 669 | blk_rq_init(q, rq); |
1afb20f3 | 670 | |
42dad764 | 671 | rq->cmd_flags = flags | REQ_ALLOCED; |
1da177e4 | 672 | |
cb98fc8b | 673 | if (priv) { |
cb78b285 | 674 | if (unlikely(elv_set_request(q, rq, gfp_mask))) { |
cb98fc8b TH |
675 | mempool_free(rq, q->rq.rq_pool); |
676 | return NULL; | |
677 | } | |
4aff5e23 | 678 | rq->cmd_flags |= REQ_ELVPRIV; |
cb98fc8b | 679 | } |
1da177e4 | 680 | |
cb98fc8b | 681 | return rq; |
1da177e4 LT |
682 | } |
683 | ||
684 | /* | |
685 | * ioc_batching returns true if the ioc is a valid batching request and | |
686 | * should be given priority access to a request. | |
687 | */ | |
165125e1 | 688 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
689 | { |
690 | if (!ioc) | |
691 | return 0; | |
692 | ||
693 | /* | |
694 | * Make sure the process is able to allocate at least 1 request | |
695 | * even if the batch times out, otherwise we could theoretically | |
696 | * lose wakeups. | |
697 | */ | |
698 | return ioc->nr_batch_requests == q->nr_batching || | |
699 | (ioc->nr_batch_requests > 0 | |
700 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
701 | } | |
702 | ||
703 | /* | |
704 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
705 | * will cause the process to be a "batcher" on all queues in the system. This | |
706 | * is the behaviour we want though - once it gets a wakeup it should be given | |
707 | * a nice run. | |
708 | */ | |
165125e1 | 709 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
710 | { |
711 | if (!ioc || ioc_batching(q, ioc)) | |
712 | return; | |
713 | ||
714 | ioc->nr_batch_requests = q->nr_batching; | |
715 | ioc->last_waited = jiffies; | |
716 | } | |
717 | ||
1faa16d2 | 718 | static void __freed_request(struct request_queue *q, int sync) |
1da177e4 LT |
719 | { |
720 | struct request_list *rl = &q->rq; | |
721 | ||
1faa16d2 JA |
722 | if (rl->count[sync] < queue_congestion_off_threshold(q)) |
723 | blk_clear_queue_congested(q, sync); | |
1da177e4 | 724 | |
1faa16d2 JA |
725 | if (rl->count[sync] + 1 <= q->nr_requests) { |
726 | if (waitqueue_active(&rl->wait[sync])) | |
727 | wake_up(&rl->wait[sync]); | |
1da177e4 | 728 | |
1faa16d2 | 729 | blk_clear_queue_full(q, sync); |
1da177e4 LT |
730 | } |
731 | } | |
732 | ||
733 | /* | |
734 | * A request has just been released. Account for it, update the full and | |
735 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
736 | */ | |
1faa16d2 | 737 | static void freed_request(struct request_queue *q, int sync, int priv) |
1da177e4 LT |
738 | { |
739 | struct request_list *rl = &q->rq; | |
740 | ||
1faa16d2 | 741 | rl->count[sync]--; |
cb98fc8b TH |
742 | if (priv) |
743 | rl->elvpriv--; | |
1da177e4 | 744 | |
1faa16d2 | 745 | __freed_request(q, sync); |
1da177e4 | 746 | |
1faa16d2 JA |
747 | if (unlikely(rl->starved[sync ^ 1])) |
748 | __freed_request(q, sync ^ 1); | |
1da177e4 LT |
749 | } |
750 | ||
1da177e4 | 751 | /* |
d6344532 NP |
752 | * Get a free request, queue_lock must be held. |
753 | * Returns NULL on failure, with queue_lock held. | |
754 | * Returns !NULL on success, with queue_lock *not held*. | |
1da177e4 | 755 | */ |
165125e1 | 756 | static struct request *get_request(struct request_queue *q, int rw_flags, |
7749a8d4 | 757 | struct bio *bio, gfp_t gfp_mask) |
1da177e4 LT |
758 | { |
759 | struct request *rq = NULL; | |
760 | struct request_list *rl = &q->rq; | |
88ee5ef1 | 761 | struct io_context *ioc = NULL; |
1faa16d2 | 762 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
88ee5ef1 JA |
763 | int may_queue, priv; |
764 | ||
7749a8d4 | 765 | may_queue = elv_may_queue(q, rw_flags); |
88ee5ef1 JA |
766 | if (may_queue == ELV_MQUEUE_NO) |
767 | goto rq_starved; | |
768 | ||
1faa16d2 JA |
769 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
770 | if (rl->count[is_sync]+1 >= q->nr_requests) { | |
b5deef90 | 771 | ioc = current_io_context(GFP_ATOMIC, q->node); |
88ee5ef1 JA |
772 | /* |
773 | * The queue will fill after this allocation, so set | |
774 | * it as full, and mark this process as "batching". | |
775 | * This process will be allowed to complete a batch of | |
776 | * requests, others will be blocked. | |
777 | */ | |
1faa16d2 | 778 | if (!blk_queue_full(q, is_sync)) { |
88ee5ef1 | 779 | ioc_set_batching(q, ioc); |
1faa16d2 | 780 | blk_set_queue_full(q, is_sync); |
88ee5ef1 JA |
781 | } else { |
782 | if (may_queue != ELV_MQUEUE_MUST | |
783 | && !ioc_batching(q, ioc)) { | |
784 | /* | |
785 | * The queue is full and the allocating | |
786 | * process is not a "batcher", and not | |
787 | * exempted by the IO scheduler | |
788 | */ | |
789 | goto out; | |
790 | } | |
791 | } | |
1da177e4 | 792 | } |
1faa16d2 | 793 | blk_set_queue_congested(q, is_sync); |
1da177e4 LT |
794 | } |
795 | ||
082cf69e JA |
796 | /* |
797 | * Only allow batching queuers to allocate up to 50% over the defined | |
798 | * limit of requests, otherwise we could have thousands of requests | |
799 | * allocated with any setting of ->nr_requests | |
800 | */ | |
1faa16d2 | 801 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
082cf69e | 802 | goto out; |
fd782a4a | 803 | |
1faa16d2 JA |
804 | rl->count[is_sync]++; |
805 | rl->starved[is_sync] = 0; | |
cb98fc8b | 806 | |
64521d1a | 807 | priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); |
7681bfee | 808 | if (priv) { |
cb98fc8b TH |
809 | rl->elvpriv++; |
810 | ||
7681bfee YI |
811 | /* |
812 | * Don't do stats for non-priv requests | |
813 | */ | |
814 | if (blk_queue_io_stat(q)) | |
815 | rw_flags |= REQ_IO_STAT; | |
816 | } | |
817 | ||
1da177e4 LT |
818 | spin_unlock_irq(q->queue_lock); |
819 | ||
7749a8d4 | 820 | rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); |
88ee5ef1 | 821 | if (unlikely(!rq)) { |
1da177e4 LT |
822 | /* |
823 | * Allocation failed presumably due to memory. Undo anything | |
824 | * we might have messed up. | |
825 | * | |
826 | * Allocating task should really be put onto the front of the | |
827 | * wait queue, but this is pretty rare. | |
828 | */ | |
829 | spin_lock_irq(q->queue_lock); | |
1faa16d2 | 830 | freed_request(q, is_sync, priv); |
1da177e4 LT |
831 | |
832 | /* | |
833 | * in the very unlikely event that allocation failed and no | |
834 | * requests for this direction was pending, mark us starved | |
835 | * so that freeing of a request in the other direction will | |
836 | * notice us. another possible fix would be to split the | |
837 | * rq mempool into READ and WRITE | |
838 | */ | |
839 | rq_starved: | |
1faa16d2 JA |
840 | if (unlikely(rl->count[is_sync] == 0)) |
841 | rl->starved[is_sync] = 1; | |
1da177e4 | 842 | |
1da177e4 LT |
843 | goto out; |
844 | } | |
845 | ||
88ee5ef1 JA |
846 | /* |
847 | * ioc may be NULL here, and ioc_batching will be false. That's | |
848 | * OK, if the queue is under the request limit then requests need | |
849 | * not count toward the nr_batch_requests limit. There will always | |
850 | * be some limit enforced by BLK_BATCH_TIME. | |
851 | */ | |
1da177e4 LT |
852 | if (ioc_batching(q, ioc)) |
853 | ioc->nr_batch_requests--; | |
6728cb0e | 854 | |
1faa16d2 | 855 | trace_block_getrq(q, bio, rw_flags & 1); |
1da177e4 | 856 | out: |
1da177e4 LT |
857 | return rq; |
858 | } | |
859 | ||
860 | /* | |
861 | * No available requests for this queue, unplug the device and wait for some | |
862 | * requests to become available. | |
d6344532 NP |
863 | * |
864 | * Called with q->queue_lock held, and returns with it unlocked. | |
1da177e4 | 865 | */ |
165125e1 | 866 | static struct request *get_request_wait(struct request_queue *q, int rw_flags, |
22e2c507 | 867 | struct bio *bio) |
1da177e4 | 868 | { |
1faa16d2 | 869 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
1da177e4 LT |
870 | struct request *rq; |
871 | ||
7749a8d4 | 872 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
450991bc NP |
873 | while (!rq) { |
874 | DEFINE_WAIT(wait); | |
05caf8db | 875 | struct io_context *ioc; |
1da177e4 LT |
876 | struct request_list *rl = &q->rq; |
877 | ||
1faa16d2 | 878 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, |
1da177e4 LT |
879 | TASK_UNINTERRUPTIBLE); |
880 | ||
1faa16d2 | 881 | trace_block_sleeprq(q, bio, rw_flags & 1); |
1da177e4 | 882 | |
05caf8db ZY |
883 | __generic_unplug_device(q); |
884 | spin_unlock_irq(q->queue_lock); | |
885 | io_schedule(); | |
1da177e4 | 886 | |
05caf8db ZY |
887 | /* |
888 | * After sleeping, we become a "batching" process and | |
889 | * will be able to allocate at least one request, and | |
890 | * up to a big batch of them for a small period time. | |
891 | * See ioc_batching, ioc_set_batching | |
892 | */ | |
893 | ioc = current_io_context(GFP_NOIO, q->node); | |
894 | ioc_set_batching(q, ioc); | |
d6344532 | 895 | |
05caf8db | 896 | spin_lock_irq(q->queue_lock); |
1faa16d2 | 897 | finish_wait(&rl->wait[is_sync], &wait); |
05caf8db ZY |
898 | |
899 | rq = get_request(q, rw_flags, bio, GFP_NOIO); | |
900 | }; | |
1da177e4 LT |
901 | |
902 | return rq; | |
903 | } | |
904 | ||
165125e1 | 905 | struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) |
1da177e4 LT |
906 | { |
907 | struct request *rq; | |
908 | ||
909 | BUG_ON(rw != READ && rw != WRITE); | |
910 | ||
d6344532 NP |
911 | spin_lock_irq(q->queue_lock); |
912 | if (gfp_mask & __GFP_WAIT) { | |
22e2c507 | 913 | rq = get_request_wait(q, rw, NULL); |
d6344532 | 914 | } else { |
22e2c507 | 915 | rq = get_request(q, rw, NULL, gfp_mask); |
d6344532 NP |
916 | if (!rq) |
917 | spin_unlock_irq(q->queue_lock); | |
918 | } | |
919 | /* q->queue_lock is unlocked at this point */ | |
1da177e4 LT |
920 | |
921 | return rq; | |
922 | } | |
1da177e4 LT |
923 | EXPORT_SYMBOL(blk_get_request); |
924 | ||
dc72ef4a | 925 | /** |
79eb63e9 | 926 | * blk_make_request - given a bio, allocate a corresponding struct request. |
8ebf9756 | 927 | * @q: target request queue |
79eb63e9 BH |
928 | * @bio: The bio describing the memory mappings that will be submitted for IO. |
929 | * It may be a chained-bio properly constructed by block/bio layer. | |
8ebf9756 | 930 | * @gfp_mask: gfp flags to be used for memory allocation |
dc72ef4a | 931 | * |
79eb63e9 BH |
932 | * blk_make_request is the parallel of generic_make_request for BLOCK_PC |
933 | * type commands. Where the struct request needs to be farther initialized by | |
934 | * the caller. It is passed a &struct bio, which describes the memory info of | |
935 | * the I/O transfer. | |
dc72ef4a | 936 | * |
79eb63e9 BH |
937 | * The caller of blk_make_request must make sure that bi_io_vec |
938 | * are set to describe the memory buffers. That bio_data_dir() will return | |
939 | * the needed direction of the request. (And all bio's in the passed bio-chain | |
940 | * are properly set accordingly) | |
941 | * | |
942 | * If called under none-sleepable conditions, mapped bio buffers must not | |
943 | * need bouncing, by calling the appropriate masked or flagged allocator, | |
944 | * suitable for the target device. Otherwise the call to blk_queue_bounce will | |
945 | * BUG. | |
53674ac5 JA |
946 | * |
947 | * WARNING: When allocating/cloning a bio-chain, careful consideration should be | |
948 | * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for | |
949 | * anything but the first bio in the chain. Otherwise you risk waiting for IO | |
950 | * completion of a bio that hasn't been submitted yet, thus resulting in a | |
951 | * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead | |
952 | * of bio_alloc(), as that avoids the mempool deadlock. | |
953 | * If possible a big IO should be split into smaller parts when allocation | |
954 | * fails. Partial allocation should not be an error, or you risk a live-lock. | |
dc72ef4a | 955 | */ |
79eb63e9 BH |
956 | struct request *blk_make_request(struct request_queue *q, struct bio *bio, |
957 | gfp_t gfp_mask) | |
dc72ef4a | 958 | { |
79eb63e9 BH |
959 | struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask); |
960 | ||
961 | if (unlikely(!rq)) | |
962 | return ERR_PTR(-ENOMEM); | |
963 | ||
964 | for_each_bio(bio) { | |
965 | struct bio *bounce_bio = bio; | |
966 | int ret; | |
967 | ||
968 | blk_queue_bounce(q, &bounce_bio); | |
969 | ret = blk_rq_append_bio(q, rq, bounce_bio); | |
970 | if (unlikely(ret)) { | |
971 | blk_put_request(rq); | |
972 | return ERR_PTR(ret); | |
973 | } | |
974 | } | |
975 | ||
976 | return rq; | |
dc72ef4a | 977 | } |
79eb63e9 | 978 | EXPORT_SYMBOL(blk_make_request); |
dc72ef4a | 979 | |
1da177e4 LT |
980 | /** |
981 | * blk_requeue_request - put a request back on queue | |
982 | * @q: request queue where request should be inserted | |
983 | * @rq: request to be inserted | |
984 | * | |
985 | * Description: | |
986 | * Drivers often keep queueing requests until the hardware cannot accept | |
987 | * more, when that condition happens we need to put the request back | |
988 | * on the queue. Must be called with queue lock held. | |
989 | */ | |
165125e1 | 990 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 991 | { |
242f9dcb JA |
992 | blk_delete_timer(rq); |
993 | blk_clear_rq_complete(rq); | |
5f3ea37c | 994 | trace_block_rq_requeue(q, rq); |
2056a782 | 995 | |
1da177e4 LT |
996 | if (blk_rq_tagged(rq)) |
997 | blk_queue_end_tag(q, rq); | |
998 | ||
ba396a6c JB |
999 | BUG_ON(blk_queued_rq(rq)); |
1000 | ||
1da177e4 LT |
1001 | elv_requeue_request(q, rq); |
1002 | } | |
1da177e4 LT |
1003 | EXPORT_SYMBOL(blk_requeue_request); |
1004 | ||
1005 | /** | |
710027a4 | 1006 | * blk_insert_request - insert a special request into a request queue |
1da177e4 LT |
1007 | * @q: request queue where request should be inserted |
1008 | * @rq: request to be inserted | |
1009 | * @at_head: insert request at head or tail of queue | |
1010 | * @data: private data | |
1da177e4 LT |
1011 | * |
1012 | * Description: | |
1013 | * Many block devices need to execute commands asynchronously, so they don't | |
1014 | * block the whole kernel from preemption during request execution. This is | |
1015 | * accomplished normally by inserting aritficial requests tagged as | |
710027a4 RD |
1016 | * REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them |
1017 | * be scheduled for actual execution by the request queue. | |
1da177e4 LT |
1018 | * |
1019 | * We have the option of inserting the head or the tail of the queue. | |
1020 | * Typically we use the tail for new ioctls and so forth. We use the head | |
1021 | * of the queue for things like a QUEUE_FULL message from a device, or a | |
1022 | * host that is unable to accept a particular command. | |
1023 | */ | |
165125e1 | 1024 | void blk_insert_request(struct request_queue *q, struct request *rq, |
867d1191 | 1025 | int at_head, void *data) |
1da177e4 | 1026 | { |
867d1191 | 1027 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; |
1da177e4 LT |
1028 | unsigned long flags; |
1029 | ||
1030 | /* | |
1031 | * tell I/O scheduler that this isn't a regular read/write (ie it | |
1032 | * must not attempt merges on this) and that it acts as a soft | |
1033 | * barrier | |
1034 | */ | |
4aff5e23 | 1035 | rq->cmd_type = REQ_TYPE_SPECIAL; |
1da177e4 LT |
1036 | |
1037 | rq->special = data; | |
1038 | ||
1039 | spin_lock_irqsave(q->queue_lock, flags); | |
1040 | ||
1041 | /* | |
1042 | * If command is tagged, release the tag | |
1043 | */ | |
867d1191 TH |
1044 | if (blk_rq_tagged(rq)) |
1045 | blk_queue_end_tag(q, rq); | |
1da177e4 | 1046 | |
b238b3d4 | 1047 | drive_stat_acct(rq, 1); |
867d1191 | 1048 | __elv_add_request(q, rq, where, 0); |
a7f55792 | 1049 | __blk_run_queue(q); |
1da177e4 LT |
1050 | spin_unlock_irqrestore(q->queue_lock, flags); |
1051 | } | |
1da177e4 LT |
1052 | EXPORT_SYMBOL(blk_insert_request); |
1053 | ||
074a7aca TH |
1054 | static void part_round_stats_single(int cpu, struct hd_struct *part, |
1055 | unsigned long now) | |
1056 | { | |
1057 | if (now == part->stamp) | |
1058 | return; | |
1059 | ||
316d315b | 1060 | if (part_in_flight(part)) { |
074a7aca | 1061 | __part_stat_add(cpu, part, time_in_queue, |
316d315b | 1062 | part_in_flight(part) * (now - part->stamp)); |
074a7aca TH |
1063 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
1064 | } | |
1065 | part->stamp = now; | |
1066 | } | |
1067 | ||
1068 | /** | |
496aa8a9 RD |
1069 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
1070 | * @cpu: cpu number for stats access | |
1071 | * @part: target partition | |
1da177e4 LT |
1072 | * |
1073 | * The average IO queue length and utilisation statistics are maintained | |
1074 | * by observing the current state of the queue length and the amount of | |
1075 | * time it has been in this state for. | |
1076 | * | |
1077 | * Normally, that accounting is done on IO completion, but that can result | |
1078 | * in more than a second's worth of IO being accounted for within any one | |
1079 | * second, leading to >100% utilisation. To deal with that, we call this | |
1080 | * function to do a round-off before returning the results when reading | |
1081 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
1082 | * the current jiffies and restarts the counters again. | |
1083 | */ | |
c9959059 | 1084 | void part_round_stats(int cpu, struct hd_struct *part) |
6f2576af JM |
1085 | { |
1086 | unsigned long now = jiffies; | |
1087 | ||
074a7aca TH |
1088 | if (part->partno) |
1089 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); | |
1090 | part_round_stats_single(cpu, part, now); | |
6f2576af | 1091 | } |
074a7aca | 1092 | EXPORT_SYMBOL_GPL(part_round_stats); |
6f2576af | 1093 | |
1da177e4 LT |
1094 | /* |
1095 | * queue lock must be held | |
1096 | */ | |
165125e1 | 1097 | void __blk_put_request(struct request_queue *q, struct request *req) |
1da177e4 | 1098 | { |
1da177e4 LT |
1099 | if (unlikely(!q)) |
1100 | return; | |
1101 | if (unlikely(--req->ref_count)) | |
1102 | return; | |
1103 | ||
8922e16c TH |
1104 | elv_completed_request(q, req); |
1105 | ||
1cd96c24 BH |
1106 | /* this is a bio leak */ |
1107 | WARN_ON(req->bio != NULL); | |
1108 | ||
1da177e4 LT |
1109 | /* |
1110 | * Request may not have originated from ll_rw_blk. if not, | |
1111 | * it didn't come out of our reserved rq pools | |
1112 | */ | |
49171e5c | 1113 | if (req->cmd_flags & REQ_ALLOCED) { |
1faa16d2 | 1114 | int is_sync = rq_is_sync(req) != 0; |
4aff5e23 | 1115 | int priv = req->cmd_flags & REQ_ELVPRIV; |
1da177e4 | 1116 | |
1da177e4 | 1117 | BUG_ON(!list_empty(&req->queuelist)); |
9817064b | 1118 | BUG_ON(!hlist_unhashed(&req->hash)); |
1da177e4 LT |
1119 | |
1120 | blk_free_request(q, req); | |
1faa16d2 | 1121 | freed_request(q, is_sync, priv); |
1da177e4 LT |
1122 | } |
1123 | } | |
6e39b69e MC |
1124 | EXPORT_SYMBOL_GPL(__blk_put_request); |
1125 | ||
1da177e4 LT |
1126 | void blk_put_request(struct request *req) |
1127 | { | |
8922e16c | 1128 | unsigned long flags; |
165125e1 | 1129 | struct request_queue *q = req->q; |
8922e16c | 1130 | |
52a93ba8 FT |
1131 | spin_lock_irqsave(q->queue_lock, flags); |
1132 | __blk_put_request(q, req); | |
1133 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1da177e4 | 1134 | } |
1da177e4 LT |
1135 | EXPORT_SYMBOL(blk_put_request); |
1136 | ||
66ac0280 CH |
1137 | /** |
1138 | * blk_add_request_payload - add a payload to a request | |
1139 | * @rq: request to update | |
1140 | * @page: page backing the payload | |
1141 | * @len: length of the payload. | |
1142 | * | |
1143 | * This allows to later add a payload to an already submitted request by | |
1144 | * a block driver. The driver needs to take care of freeing the payload | |
1145 | * itself. | |
1146 | * | |
1147 | * Note that this is a quite horrible hack and nothing but handling of | |
1148 | * discard requests should ever use it. | |
1149 | */ | |
1150 | void blk_add_request_payload(struct request *rq, struct page *page, | |
1151 | unsigned int len) | |
1152 | { | |
1153 | struct bio *bio = rq->bio; | |
1154 | ||
1155 | bio->bi_io_vec->bv_page = page; | |
1156 | bio->bi_io_vec->bv_offset = 0; | |
1157 | bio->bi_io_vec->bv_len = len; | |
1158 | ||
1159 | bio->bi_size = len; | |
1160 | bio->bi_vcnt = 1; | |
1161 | bio->bi_phys_segments = 1; | |
1162 | ||
1163 | rq->__data_len = rq->resid_len = len; | |
1164 | rq->nr_phys_segments = 1; | |
1165 | rq->buffer = bio_data(bio); | |
1166 | } | |
1167 | EXPORT_SYMBOL_GPL(blk_add_request_payload); | |
1168 | ||
86db1e29 | 1169 | void init_request_from_bio(struct request *req, struct bio *bio) |
52d9e675 | 1170 | { |
c7c22e4d | 1171 | req->cpu = bio->bi_comp_cpu; |
4aff5e23 | 1172 | req->cmd_type = REQ_TYPE_FS; |
52d9e675 | 1173 | |
7b6d91da CH |
1174 | req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK; |
1175 | if (bio->bi_rw & REQ_RAHEAD) | |
a82afdfc | 1176 | req->cmd_flags |= REQ_FAILFAST_MASK; |
b31dc66a | 1177 | |
52d9e675 | 1178 | req->errors = 0; |
a2dec7b3 | 1179 | req->__sector = bio->bi_sector; |
52d9e675 | 1180 | req->ioprio = bio_prio(bio); |
bc1c56fd | 1181 | blk_rq_bio_prep(req->q, req, bio); |
52d9e675 TH |
1182 | } |
1183 | ||
644b2d99 JA |
1184 | /* |
1185 | * Only disabling plugging for non-rotational devices if it does tagging | |
1186 | * as well, otherwise we do need the proper merging | |
1187 | */ | |
1188 | static inline bool queue_should_plug(struct request_queue *q) | |
1189 | { | |
79da0644 | 1190 | return !(blk_queue_nonrot(q) && blk_queue_tagged(q)); |
644b2d99 JA |
1191 | } |
1192 | ||
165125e1 | 1193 | static int __make_request(struct request_queue *q, struct bio *bio) |
1da177e4 | 1194 | { |
450991bc | 1195 | struct request *req; |
2e46e8b2 TH |
1196 | int el_ret; |
1197 | unsigned int bytes = bio->bi_size; | |
51da90fc | 1198 | const unsigned short prio = bio_prio(bio); |
5e00d1b5 JS |
1199 | const bool sync = !!(bio->bi_rw & REQ_SYNC); |
1200 | const bool unplug = !!(bio->bi_rw & REQ_UNPLUG); | |
1201 | const unsigned long ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
28e7d184 | 1202 | int where = ELEVATOR_INSERT_SORT; |
7749a8d4 | 1203 | int rw_flags; |
1da177e4 | 1204 | |
4913efe4 TH |
1205 | /* REQ_HARDBARRIER is no more */ |
1206 | if (WARN_ONCE(bio->bi_rw & REQ_HARDBARRIER, | |
1207 | "block: HARDBARRIER is deprecated, use FLUSH/FUA instead\n")) { | |
db64f680 N |
1208 | bio_endio(bio, -EOPNOTSUPP); |
1209 | return 0; | |
1210 | } | |
4913efe4 | 1211 | |
1da177e4 LT |
1212 | /* |
1213 | * low level driver can indicate that it wants pages above a | |
1214 | * certain limit bounced to low memory (ie for highmem, or even | |
1215 | * ISA dma in theory) | |
1216 | */ | |
1217 | blk_queue_bounce(q, &bio); | |
1218 | ||
1da177e4 LT |
1219 | spin_lock_irq(q->queue_lock); |
1220 | ||
4fed947c | 1221 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { |
28e7d184 TH |
1222 | where = ELEVATOR_INSERT_FRONT; |
1223 | goto get_rq; | |
1224 | } | |
1225 | ||
1226 | if (elv_queue_empty(q)) | |
1da177e4 LT |
1227 | goto get_rq; |
1228 | ||
1229 | el_ret = elv_merge(q, &req, bio); | |
1230 | switch (el_ret) { | |
6728cb0e JA |
1231 | case ELEVATOR_BACK_MERGE: |
1232 | BUG_ON(!rq_mergeable(req)); | |
1da177e4 | 1233 | |
6728cb0e JA |
1234 | if (!ll_back_merge_fn(q, req, bio)) |
1235 | break; | |
1da177e4 | 1236 | |
5f3ea37c | 1237 | trace_block_bio_backmerge(q, bio); |
2056a782 | 1238 | |
80a761fd TH |
1239 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) |
1240 | blk_rq_set_mixed_merge(req); | |
1241 | ||
6728cb0e JA |
1242 | req->biotail->bi_next = bio; |
1243 | req->biotail = bio; | |
a2dec7b3 | 1244 | req->__data_len += bytes; |
6728cb0e | 1245 | req->ioprio = ioprio_best(req->ioprio, prio); |
ab780f1e JA |
1246 | if (!blk_rq_cpu_valid(req)) |
1247 | req->cpu = bio->bi_comp_cpu; | |
6728cb0e | 1248 | drive_stat_acct(req, 0); |
812d4026 | 1249 | elv_bio_merged(q, req, bio); |
6728cb0e JA |
1250 | if (!attempt_back_merge(q, req)) |
1251 | elv_merged_request(q, req, el_ret); | |
1252 | goto out; | |
1da177e4 | 1253 | |
6728cb0e JA |
1254 | case ELEVATOR_FRONT_MERGE: |
1255 | BUG_ON(!rq_mergeable(req)); | |
1da177e4 | 1256 | |
6728cb0e JA |
1257 | if (!ll_front_merge_fn(q, req, bio)) |
1258 | break; | |
1da177e4 | 1259 | |
5f3ea37c | 1260 | trace_block_bio_frontmerge(q, bio); |
2056a782 | 1261 | |
80a761fd TH |
1262 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) { |
1263 | blk_rq_set_mixed_merge(req); | |
1264 | req->cmd_flags &= ~REQ_FAILFAST_MASK; | |
1265 | req->cmd_flags |= ff; | |
1266 | } | |
1267 | ||
6728cb0e JA |
1268 | bio->bi_next = req->bio; |
1269 | req->bio = bio; | |
1da177e4 | 1270 | |
6728cb0e JA |
1271 | /* |
1272 | * may not be valid. if the low level driver said | |
1273 | * it didn't need a bounce buffer then it better | |
1274 | * not touch req->buffer either... | |
1275 | */ | |
1276 | req->buffer = bio_data(bio); | |
a2dec7b3 TH |
1277 | req->__sector = bio->bi_sector; |
1278 | req->__data_len += bytes; | |
6728cb0e | 1279 | req->ioprio = ioprio_best(req->ioprio, prio); |
ab780f1e JA |
1280 | if (!blk_rq_cpu_valid(req)) |
1281 | req->cpu = bio->bi_comp_cpu; | |
6728cb0e | 1282 | drive_stat_acct(req, 0); |
812d4026 | 1283 | elv_bio_merged(q, req, bio); |
6728cb0e JA |
1284 | if (!attempt_front_merge(q, req)) |
1285 | elv_merged_request(q, req, el_ret); | |
1286 | goto out; | |
1287 | ||
1288 | /* ELV_NO_MERGE: elevator says don't/can't merge. */ | |
1289 | default: | |
1290 | ; | |
1da177e4 LT |
1291 | } |
1292 | ||
450991bc | 1293 | get_rq: |
7749a8d4 JA |
1294 | /* |
1295 | * This sync check and mask will be re-done in init_request_from_bio(), | |
1296 | * but we need to set it earlier to expose the sync flag to the | |
1297 | * rq allocator and io schedulers. | |
1298 | */ | |
1299 | rw_flags = bio_data_dir(bio); | |
1300 | if (sync) | |
7b6d91da | 1301 | rw_flags |= REQ_SYNC; |
7749a8d4 | 1302 | |
1da177e4 | 1303 | /* |
450991bc | 1304 | * Grab a free request. This is might sleep but can not fail. |
d6344532 | 1305 | * Returns with the queue unlocked. |
450991bc | 1306 | */ |
7749a8d4 | 1307 | req = get_request_wait(q, rw_flags, bio); |
d6344532 | 1308 | |
450991bc NP |
1309 | /* |
1310 | * After dropping the lock and possibly sleeping here, our request | |
1311 | * may now be mergeable after it had proven unmergeable (above). | |
1312 | * We don't worry about that case for efficiency. It won't happen | |
1313 | * often, and the elevators are able to handle it. | |
1da177e4 | 1314 | */ |
52d9e675 | 1315 | init_request_from_bio(req, bio); |
1da177e4 | 1316 | |
450991bc | 1317 | spin_lock_irq(q->queue_lock); |
c7c22e4d JA |
1318 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) || |
1319 | bio_flagged(bio, BIO_CPU_AFFINE)) | |
1320 | req->cpu = blk_cpu_to_group(smp_processor_id()); | |
644b2d99 | 1321 | if (queue_should_plug(q) && elv_queue_empty(q)) |
450991bc | 1322 | blk_plug_device(q); |
dd831006 TH |
1323 | |
1324 | /* insert the request into the elevator */ | |
1325 | drive_stat_acct(req, 1); | |
28e7d184 | 1326 | __elv_add_request(q, req, where, 0); |
1da177e4 | 1327 | out: |
644b2d99 | 1328 | if (unplug || !queue_should_plug(q)) |
1da177e4 | 1329 | __generic_unplug_device(q); |
1da177e4 LT |
1330 | spin_unlock_irq(q->queue_lock); |
1331 | return 0; | |
1da177e4 LT |
1332 | } |
1333 | ||
1334 | /* | |
1335 | * If bio->bi_dev is a partition, remap the location | |
1336 | */ | |
1337 | static inline void blk_partition_remap(struct bio *bio) | |
1338 | { | |
1339 | struct block_device *bdev = bio->bi_bdev; | |
1340 | ||
bf2de6f5 | 1341 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
1da177e4 LT |
1342 | struct hd_struct *p = bdev->bd_part; |
1343 | ||
1da177e4 LT |
1344 | bio->bi_sector += p->start_sect; |
1345 | bio->bi_bdev = bdev->bd_contains; | |
c7149d6b | 1346 | |
5f3ea37c | 1347 | trace_block_remap(bdev_get_queue(bio->bi_bdev), bio, |
22a7c31a | 1348 | bdev->bd_dev, |
c7149d6b | 1349 | bio->bi_sector - p->start_sect); |
1da177e4 LT |
1350 | } |
1351 | } | |
1352 | ||
1da177e4 LT |
1353 | static void handle_bad_sector(struct bio *bio) |
1354 | { | |
1355 | char b[BDEVNAME_SIZE]; | |
1356 | ||
1357 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
1358 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", | |
1359 | bdevname(bio->bi_bdev, b), | |
1360 | bio->bi_rw, | |
1361 | (unsigned long long)bio->bi_sector + bio_sectors(bio), | |
1362 | (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); | |
1363 | ||
1364 | set_bit(BIO_EOF, &bio->bi_flags); | |
1365 | } | |
1366 | ||
c17bb495 AM |
1367 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
1368 | ||
1369 | static DECLARE_FAULT_ATTR(fail_make_request); | |
1370 | ||
1371 | static int __init setup_fail_make_request(char *str) | |
1372 | { | |
1373 | return setup_fault_attr(&fail_make_request, str); | |
1374 | } | |
1375 | __setup("fail_make_request=", setup_fail_make_request); | |
1376 | ||
1377 | static int should_fail_request(struct bio *bio) | |
1378 | { | |
eddb2e26 TH |
1379 | struct hd_struct *part = bio->bi_bdev->bd_part; |
1380 | ||
1381 | if (part_to_disk(part)->part0.make_it_fail || part->make_it_fail) | |
c17bb495 AM |
1382 | return should_fail(&fail_make_request, bio->bi_size); |
1383 | ||
1384 | return 0; | |
1385 | } | |
1386 | ||
1387 | static int __init fail_make_request_debugfs(void) | |
1388 | { | |
1389 | return init_fault_attr_dentries(&fail_make_request, | |
1390 | "fail_make_request"); | |
1391 | } | |
1392 | ||
1393 | late_initcall(fail_make_request_debugfs); | |
1394 | ||
1395 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
1396 | ||
1397 | static inline int should_fail_request(struct bio *bio) | |
1398 | { | |
1399 | return 0; | |
1400 | } | |
1401 | ||
1402 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
1403 | ||
c07e2b41 JA |
1404 | /* |
1405 | * Check whether this bio extends beyond the end of the device. | |
1406 | */ | |
1407 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) | |
1408 | { | |
1409 | sector_t maxsector; | |
1410 | ||
1411 | if (!nr_sectors) | |
1412 | return 0; | |
1413 | ||
1414 | /* Test device or partition size, when known. */ | |
1415 | maxsector = bio->bi_bdev->bd_inode->i_size >> 9; | |
1416 | if (maxsector) { | |
1417 | sector_t sector = bio->bi_sector; | |
1418 | ||
1419 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { | |
1420 | /* | |
1421 | * This may well happen - the kernel calls bread() | |
1422 | * without checking the size of the device, e.g., when | |
1423 | * mounting a device. | |
1424 | */ | |
1425 | handle_bad_sector(bio); | |
1426 | return 1; | |
1427 | } | |
1428 | } | |
1429 | ||
1430 | return 0; | |
1431 | } | |
1432 | ||
1da177e4 | 1433 | /** |
710027a4 | 1434 | * generic_make_request - hand a buffer to its device driver for I/O |
1da177e4 LT |
1435 | * @bio: The bio describing the location in memory and on the device. |
1436 | * | |
1437 | * generic_make_request() is used to make I/O requests of block | |
1438 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
1439 | * to be done. | |
1440 | * | |
1441 | * generic_make_request() does not return any status. The | |
1442 | * success/failure status of the request, along with notification of | |
1443 | * completion, is delivered asynchronously through the bio->bi_end_io | |
1444 | * function described (one day) else where. | |
1445 | * | |
1446 | * The caller of generic_make_request must make sure that bi_io_vec | |
1447 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
1448 | * set to describe the device address, and the | |
1449 | * bi_end_io and optionally bi_private are set to describe how | |
1450 | * completion notification should be signaled. | |
1451 | * | |
1452 | * generic_make_request and the drivers it calls may use bi_next if this | |
1453 | * bio happens to be merged with someone else, and may change bi_dev and | |
1454 | * bi_sector for remaps as it sees fit. So the values of these fields | |
1455 | * should NOT be depended on after the call to generic_make_request. | |
1456 | */ | |
d89d8796 | 1457 | static inline void __generic_make_request(struct bio *bio) |
1da177e4 | 1458 | { |
165125e1 | 1459 | struct request_queue *q; |
5ddfe969 | 1460 | sector_t old_sector; |
1da177e4 | 1461 | int ret, nr_sectors = bio_sectors(bio); |
2056a782 | 1462 | dev_t old_dev; |
51fd77bd | 1463 | int err = -EIO; |
1da177e4 LT |
1464 | |
1465 | might_sleep(); | |
1da177e4 | 1466 | |
c07e2b41 JA |
1467 | if (bio_check_eod(bio, nr_sectors)) |
1468 | goto end_io; | |
1da177e4 LT |
1469 | |
1470 | /* | |
1471 | * Resolve the mapping until finished. (drivers are | |
1472 | * still free to implement/resolve their own stacking | |
1473 | * by explicitly returning 0) | |
1474 | * | |
1475 | * NOTE: we don't repeat the blk_size check for each new device. | |
1476 | * Stacking drivers are expected to know what they are doing. | |
1477 | */ | |
5ddfe969 | 1478 | old_sector = -1; |
2056a782 | 1479 | old_dev = 0; |
1da177e4 LT |
1480 | do { |
1481 | char b[BDEVNAME_SIZE]; | |
1482 | ||
1483 | q = bdev_get_queue(bio->bi_bdev); | |
a7384677 | 1484 | if (unlikely(!q)) { |
1da177e4 LT |
1485 | printk(KERN_ERR |
1486 | "generic_make_request: Trying to access " | |
1487 | "nonexistent block-device %s (%Lu)\n", | |
1488 | bdevname(bio->bi_bdev, b), | |
1489 | (long long) bio->bi_sector); | |
a7384677 | 1490 | goto end_io; |
1da177e4 LT |
1491 | } |
1492 | ||
7b6d91da | 1493 | if (unlikely(!(bio->bi_rw & REQ_DISCARD) && |
67efc925 | 1494 | nr_sectors > queue_max_hw_sectors(q))) { |
6728cb0e | 1495 | printk(KERN_ERR "bio too big device %s (%u > %u)\n", |
ae03bf63 MP |
1496 | bdevname(bio->bi_bdev, b), |
1497 | bio_sectors(bio), | |
1498 | queue_max_hw_sectors(q)); | |
1da177e4 LT |
1499 | goto end_io; |
1500 | } | |
1501 | ||
fde6ad22 | 1502 | if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) |
1da177e4 LT |
1503 | goto end_io; |
1504 | ||
c17bb495 AM |
1505 | if (should_fail_request(bio)) |
1506 | goto end_io; | |
1507 | ||
1da177e4 LT |
1508 | /* |
1509 | * If this device has partitions, remap block n | |
1510 | * of partition p to block n+start(p) of the disk. | |
1511 | */ | |
1512 | blk_partition_remap(bio); | |
1513 | ||
7ba1ba12 MP |
1514 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) |
1515 | goto end_io; | |
1516 | ||
5ddfe969 | 1517 | if (old_sector != -1) |
22a7c31a | 1518 | trace_block_remap(q, bio, old_dev, old_sector); |
2056a782 | 1519 | |
5ddfe969 | 1520 | old_sector = bio->bi_sector; |
2056a782 JA |
1521 | old_dev = bio->bi_bdev->bd_dev; |
1522 | ||
c07e2b41 JA |
1523 | if (bio_check_eod(bio, nr_sectors)) |
1524 | goto end_io; | |
a7384677 | 1525 | |
1e87901e TH |
1526 | /* |
1527 | * Filter flush bio's early so that make_request based | |
1528 | * drivers without flush support don't have to worry | |
1529 | * about them. | |
1530 | */ | |
1531 | if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) { | |
1532 | bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA); | |
1533 | if (!nr_sectors) { | |
1534 | err = 0; | |
1535 | goto end_io; | |
1536 | } | |
1537 | } | |
1538 | ||
8d57a98c AH |
1539 | if ((bio->bi_rw & REQ_DISCARD) && |
1540 | (!blk_queue_discard(q) || | |
1541 | ((bio->bi_rw & REQ_SECURE) && | |
1542 | !blk_queue_secdiscard(q)))) { | |
51fd77bd JA |
1543 | err = -EOPNOTSUPP; |
1544 | goto end_io; | |
1545 | } | |
5ddfe969 | 1546 | |
e43473b7 VG |
1547 | blk_throtl_bio(q, &bio); |
1548 | ||
1549 | /* | |
1550 | * If bio = NULL, bio has been throttled and will be submitted | |
1551 | * later. | |
1552 | */ | |
1553 | if (!bio) | |
1554 | break; | |
1555 | ||
01edede4 MK |
1556 | trace_block_bio_queue(q, bio); |
1557 | ||
1da177e4 LT |
1558 | ret = q->make_request_fn(q, bio); |
1559 | } while (ret); | |
a7384677 TH |
1560 | |
1561 | return; | |
1562 | ||
1563 | end_io: | |
1564 | bio_endio(bio, err); | |
1da177e4 LT |
1565 | } |
1566 | ||
d89d8796 NB |
1567 | /* |
1568 | * We only want one ->make_request_fn to be active at a time, | |
1569 | * else stack usage with stacked devices could be a problem. | |
bddd87c7 | 1570 | * So use current->bio_list to keep a list of requests |
d89d8796 | 1571 | * submited by a make_request_fn function. |
bddd87c7 | 1572 | * current->bio_list is also used as a flag to say if |
d89d8796 NB |
1573 | * generic_make_request is currently active in this task or not. |
1574 | * If it is NULL, then no make_request is active. If it is non-NULL, | |
1575 | * then a make_request is active, and new requests should be added | |
1576 | * at the tail | |
1577 | */ | |
1578 | void generic_make_request(struct bio *bio) | |
1579 | { | |
bddd87c7 AM |
1580 | struct bio_list bio_list_on_stack; |
1581 | ||
1582 | if (current->bio_list) { | |
d89d8796 | 1583 | /* make_request is active */ |
bddd87c7 | 1584 | bio_list_add(current->bio_list, bio); |
d89d8796 NB |
1585 | return; |
1586 | } | |
1587 | /* following loop may be a bit non-obvious, and so deserves some | |
1588 | * explanation. | |
1589 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
1590 | * ensure that) so we have a list with a single bio. | |
1591 | * We pretend that we have just taken it off a longer list, so | |
bddd87c7 AM |
1592 | * we assign bio_list to a pointer to the bio_list_on_stack, |
1593 | * thus initialising the bio_list of new bios to be | |
d89d8796 NB |
1594 | * added. __generic_make_request may indeed add some more bios |
1595 | * through a recursive call to generic_make_request. If it | |
1596 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
1597 | * from the top. In this case we really did just take the bio | |
bddd87c7 AM |
1598 | * of the top of the list (no pretending) and so remove it from |
1599 | * bio_list, and call into __generic_make_request again. | |
d89d8796 NB |
1600 | * |
1601 | * The loop was structured like this to make only one call to | |
1602 | * __generic_make_request (which is important as it is large and | |
1603 | * inlined) and to keep the structure simple. | |
1604 | */ | |
1605 | BUG_ON(bio->bi_next); | |
bddd87c7 AM |
1606 | bio_list_init(&bio_list_on_stack); |
1607 | current->bio_list = &bio_list_on_stack; | |
d89d8796 | 1608 | do { |
d89d8796 | 1609 | __generic_make_request(bio); |
bddd87c7 | 1610 | bio = bio_list_pop(current->bio_list); |
d89d8796 | 1611 | } while (bio); |
bddd87c7 | 1612 | current->bio_list = NULL; /* deactivate */ |
d89d8796 | 1613 | } |
1da177e4 LT |
1614 | EXPORT_SYMBOL(generic_make_request); |
1615 | ||
1616 | /** | |
710027a4 | 1617 | * submit_bio - submit a bio to the block device layer for I/O |
1da177e4 LT |
1618 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
1619 | * @bio: The &struct bio which describes the I/O | |
1620 | * | |
1621 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
1622 | * uses that function to do most of the work. Both are fairly rough | |
710027a4 | 1623 | * interfaces; @bio must be presetup and ready for I/O. |
1da177e4 LT |
1624 | * |
1625 | */ | |
1626 | void submit_bio(int rw, struct bio *bio) | |
1627 | { | |
1628 | int count = bio_sectors(bio); | |
1629 | ||
22e2c507 | 1630 | bio->bi_rw |= rw; |
1da177e4 | 1631 | |
bf2de6f5 JA |
1632 | /* |
1633 | * If it's a regular read/write or a barrier with data attached, | |
1634 | * go through the normal accounting stuff before submission. | |
1635 | */ | |
3ffb52e7 | 1636 | if (bio_has_data(bio) && !(rw & REQ_DISCARD)) { |
bf2de6f5 JA |
1637 | if (rw & WRITE) { |
1638 | count_vm_events(PGPGOUT, count); | |
1639 | } else { | |
1640 | task_io_account_read(bio->bi_size); | |
1641 | count_vm_events(PGPGIN, count); | |
1642 | } | |
1643 | ||
1644 | if (unlikely(block_dump)) { | |
1645 | char b[BDEVNAME_SIZE]; | |
8dcbdc74 | 1646 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", |
ba25f9dc | 1647 | current->comm, task_pid_nr(current), |
bf2de6f5 JA |
1648 | (rw & WRITE) ? "WRITE" : "READ", |
1649 | (unsigned long long)bio->bi_sector, | |
8dcbdc74 SM |
1650 | bdevname(bio->bi_bdev, b), |
1651 | count); | |
bf2de6f5 | 1652 | } |
1da177e4 LT |
1653 | } |
1654 | ||
1655 | generic_make_request(bio); | |
1656 | } | |
1da177e4 LT |
1657 | EXPORT_SYMBOL(submit_bio); |
1658 | ||
82124d60 KU |
1659 | /** |
1660 | * blk_rq_check_limits - Helper function to check a request for the queue limit | |
1661 | * @q: the queue | |
1662 | * @rq: the request being checked | |
1663 | * | |
1664 | * Description: | |
1665 | * @rq may have been made based on weaker limitations of upper-level queues | |
1666 | * in request stacking drivers, and it may violate the limitation of @q. | |
1667 | * Since the block layer and the underlying device driver trust @rq | |
1668 | * after it is inserted to @q, it should be checked against @q before | |
1669 | * the insertion using this generic function. | |
1670 | * | |
1671 | * This function should also be useful for request stacking drivers | |
eef35c2d | 1672 | * in some cases below, so export this function. |
82124d60 KU |
1673 | * Request stacking drivers like request-based dm may change the queue |
1674 | * limits while requests are in the queue (e.g. dm's table swapping). | |
1675 | * Such request stacking drivers should check those requests agaist | |
1676 | * the new queue limits again when they dispatch those requests, | |
1677 | * although such checkings are also done against the old queue limits | |
1678 | * when submitting requests. | |
1679 | */ | |
1680 | int blk_rq_check_limits(struct request_queue *q, struct request *rq) | |
1681 | { | |
3383977f S |
1682 | if (rq->cmd_flags & REQ_DISCARD) |
1683 | return 0; | |
1684 | ||
ae03bf63 MP |
1685 | if (blk_rq_sectors(rq) > queue_max_sectors(q) || |
1686 | blk_rq_bytes(rq) > queue_max_hw_sectors(q) << 9) { | |
82124d60 KU |
1687 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
1688 | return -EIO; | |
1689 | } | |
1690 | ||
1691 | /* | |
1692 | * queue's settings related to segment counting like q->bounce_pfn | |
1693 | * may differ from that of other stacking queues. | |
1694 | * Recalculate it to check the request correctly on this queue's | |
1695 | * limitation. | |
1696 | */ | |
1697 | blk_recalc_rq_segments(rq); | |
8a78362c | 1698 | if (rq->nr_phys_segments > queue_max_segments(q)) { |
82124d60 KU |
1699 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
1700 | return -EIO; | |
1701 | } | |
1702 | ||
1703 | return 0; | |
1704 | } | |
1705 | EXPORT_SYMBOL_GPL(blk_rq_check_limits); | |
1706 | ||
1707 | /** | |
1708 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request | |
1709 | * @q: the queue to submit the request | |
1710 | * @rq: the request being queued | |
1711 | */ | |
1712 | int blk_insert_cloned_request(struct request_queue *q, struct request *rq) | |
1713 | { | |
1714 | unsigned long flags; | |
1715 | ||
1716 | if (blk_rq_check_limits(q, rq)) | |
1717 | return -EIO; | |
1718 | ||
1719 | #ifdef CONFIG_FAIL_MAKE_REQUEST | |
1720 | if (rq->rq_disk && rq->rq_disk->part0.make_it_fail && | |
1721 | should_fail(&fail_make_request, blk_rq_bytes(rq))) | |
1722 | return -EIO; | |
1723 | #endif | |
1724 | ||
1725 | spin_lock_irqsave(q->queue_lock, flags); | |
1726 | ||
1727 | /* | |
1728 | * Submitting request must be dequeued before calling this function | |
1729 | * because it will be linked to another request_queue | |
1730 | */ | |
1731 | BUG_ON(blk_queued_rq(rq)); | |
1732 | ||
1733 | drive_stat_acct(rq, 1); | |
1734 | __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); | |
1735 | ||
1736 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1737 | ||
1738 | return 0; | |
1739 | } | |
1740 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); | |
1741 | ||
80a761fd TH |
1742 | /** |
1743 | * blk_rq_err_bytes - determine number of bytes till the next failure boundary | |
1744 | * @rq: request to examine | |
1745 | * | |
1746 | * Description: | |
1747 | * A request could be merge of IOs which require different failure | |
1748 | * handling. This function determines the number of bytes which | |
1749 | * can be failed from the beginning of the request without | |
1750 | * crossing into area which need to be retried further. | |
1751 | * | |
1752 | * Return: | |
1753 | * The number of bytes to fail. | |
1754 | * | |
1755 | * Context: | |
1756 | * queue_lock must be held. | |
1757 | */ | |
1758 | unsigned int blk_rq_err_bytes(const struct request *rq) | |
1759 | { | |
1760 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
1761 | unsigned int bytes = 0; | |
1762 | struct bio *bio; | |
1763 | ||
1764 | if (!(rq->cmd_flags & REQ_MIXED_MERGE)) | |
1765 | return blk_rq_bytes(rq); | |
1766 | ||
1767 | /* | |
1768 | * Currently the only 'mixing' which can happen is between | |
1769 | * different fastfail types. We can safely fail portions | |
1770 | * which have all the failfast bits that the first one has - | |
1771 | * the ones which are at least as eager to fail as the first | |
1772 | * one. | |
1773 | */ | |
1774 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
1775 | if ((bio->bi_rw & ff) != ff) | |
1776 | break; | |
1777 | bytes += bio->bi_size; | |
1778 | } | |
1779 | ||
1780 | /* this could lead to infinite loop */ | |
1781 | BUG_ON(blk_rq_bytes(rq) && !bytes); | |
1782 | return bytes; | |
1783 | } | |
1784 | EXPORT_SYMBOL_GPL(blk_rq_err_bytes); | |
1785 | ||
bc58ba94 JA |
1786 | static void blk_account_io_completion(struct request *req, unsigned int bytes) |
1787 | { | |
c2553b58 | 1788 | if (blk_do_io_stat(req)) { |
bc58ba94 JA |
1789 | const int rw = rq_data_dir(req); |
1790 | struct hd_struct *part; | |
1791 | int cpu; | |
1792 | ||
1793 | cpu = part_stat_lock(); | |
7681bfee | 1794 | part = req->part; |
bc58ba94 JA |
1795 | part_stat_add(cpu, part, sectors[rw], bytes >> 9); |
1796 | part_stat_unlock(); | |
1797 | } | |
1798 | } | |
1799 | ||
1800 | static void blk_account_io_done(struct request *req) | |
1801 | { | |
bc58ba94 | 1802 | /* |
dd4c133f TH |
1803 | * Account IO completion. flush_rq isn't accounted as a |
1804 | * normal IO on queueing nor completion. Accounting the | |
1805 | * containing request is enough. | |
bc58ba94 | 1806 | */ |
dd4c133f | 1807 | if (blk_do_io_stat(req) && req != &req->q->flush_rq) { |
bc58ba94 JA |
1808 | unsigned long duration = jiffies - req->start_time; |
1809 | const int rw = rq_data_dir(req); | |
1810 | struct hd_struct *part; | |
1811 | int cpu; | |
1812 | ||
1813 | cpu = part_stat_lock(); | |
7681bfee | 1814 | part = req->part; |
bc58ba94 JA |
1815 | |
1816 | part_stat_inc(cpu, part, ios[rw]); | |
1817 | part_stat_add(cpu, part, ticks[rw], duration); | |
1818 | part_round_stats(cpu, part); | |
316d315b | 1819 | part_dec_in_flight(part, rw); |
bc58ba94 JA |
1820 | |
1821 | part_stat_unlock(); | |
1822 | } | |
1823 | } | |
1824 | ||
3bcddeac | 1825 | /** |
9934c8c0 TH |
1826 | * blk_peek_request - peek at the top of a request queue |
1827 | * @q: request queue to peek at | |
1828 | * | |
1829 | * Description: | |
1830 | * Return the request at the top of @q. The returned request | |
1831 | * should be started using blk_start_request() before LLD starts | |
1832 | * processing it. | |
1833 | * | |
1834 | * Return: | |
1835 | * Pointer to the request at the top of @q if available. Null | |
1836 | * otherwise. | |
1837 | * | |
1838 | * Context: | |
1839 | * queue_lock must be held. | |
1840 | */ | |
1841 | struct request *blk_peek_request(struct request_queue *q) | |
158dbda0 TH |
1842 | { |
1843 | struct request *rq; | |
1844 | int ret; | |
1845 | ||
1846 | while ((rq = __elv_next_request(q)) != NULL) { | |
1847 | if (!(rq->cmd_flags & REQ_STARTED)) { | |
1848 | /* | |
1849 | * This is the first time the device driver | |
1850 | * sees this request (possibly after | |
1851 | * requeueing). Notify IO scheduler. | |
1852 | */ | |
33659ebb | 1853 | if (rq->cmd_flags & REQ_SORTED) |
158dbda0 TH |
1854 | elv_activate_rq(q, rq); |
1855 | ||
1856 | /* | |
1857 | * just mark as started even if we don't start | |
1858 | * it, a request that has been delayed should | |
1859 | * not be passed by new incoming requests | |
1860 | */ | |
1861 | rq->cmd_flags |= REQ_STARTED; | |
1862 | trace_block_rq_issue(q, rq); | |
1863 | } | |
1864 | ||
1865 | if (!q->boundary_rq || q->boundary_rq == rq) { | |
1866 | q->end_sector = rq_end_sector(rq); | |
1867 | q->boundary_rq = NULL; | |
1868 | } | |
1869 | ||
1870 | if (rq->cmd_flags & REQ_DONTPREP) | |
1871 | break; | |
1872 | ||
2e46e8b2 | 1873 | if (q->dma_drain_size && blk_rq_bytes(rq)) { |
158dbda0 TH |
1874 | /* |
1875 | * make sure space for the drain appears we | |
1876 | * know we can do this because max_hw_segments | |
1877 | * has been adjusted to be one fewer than the | |
1878 | * device can handle | |
1879 | */ | |
1880 | rq->nr_phys_segments++; | |
1881 | } | |
1882 | ||
1883 | if (!q->prep_rq_fn) | |
1884 | break; | |
1885 | ||
1886 | ret = q->prep_rq_fn(q, rq); | |
1887 | if (ret == BLKPREP_OK) { | |
1888 | break; | |
1889 | } else if (ret == BLKPREP_DEFER) { | |
1890 | /* | |
1891 | * the request may have been (partially) prepped. | |
1892 | * we need to keep this request in the front to | |
1893 | * avoid resource deadlock. REQ_STARTED will | |
1894 | * prevent other fs requests from passing this one. | |
1895 | */ | |
2e46e8b2 | 1896 | if (q->dma_drain_size && blk_rq_bytes(rq) && |
158dbda0 TH |
1897 | !(rq->cmd_flags & REQ_DONTPREP)) { |
1898 | /* | |
1899 | * remove the space for the drain we added | |
1900 | * so that we don't add it again | |
1901 | */ | |
1902 | --rq->nr_phys_segments; | |
1903 | } | |
1904 | ||
1905 | rq = NULL; | |
1906 | break; | |
1907 | } else if (ret == BLKPREP_KILL) { | |
1908 | rq->cmd_flags |= REQ_QUIET; | |
c143dc90 JB |
1909 | /* |
1910 | * Mark this request as started so we don't trigger | |
1911 | * any debug logic in the end I/O path. | |
1912 | */ | |
1913 | blk_start_request(rq); | |
40cbbb78 | 1914 | __blk_end_request_all(rq, -EIO); |
158dbda0 TH |
1915 | } else { |
1916 | printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); | |
1917 | break; | |
1918 | } | |
1919 | } | |
1920 | ||
1921 | return rq; | |
1922 | } | |
9934c8c0 | 1923 | EXPORT_SYMBOL(blk_peek_request); |
158dbda0 | 1924 | |
9934c8c0 | 1925 | void blk_dequeue_request(struct request *rq) |
158dbda0 | 1926 | { |
9934c8c0 TH |
1927 | struct request_queue *q = rq->q; |
1928 | ||
158dbda0 TH |
1929 | BUG_ON(list_empty(&rq->queuelist)); |
1930 | BUG_ON(ELV_ON_HASH(rq)); | |
1931 | ||
1932 | list_del_init(&rq->queuelist); | |
1933 | ||
1934 | /* | |
1935 | * the time frame between a request being removed from the lists | |
1936 | * and to it is freed is accounted as io that is in progress at | |
1937 | * the driver side. | |
1938 | */ | |
9195291e | 1939 | if (blk_account_rq(rq)) { |
0a7ae2ff | 1940 | q->in_flight[rq_is_sync(rq)]++; |
9195291e DS |
1941 | set_io_start_time_ns(rq); |
1942 | } | |
158dbda0 TH |
1943 | } |
1944 | ||
9934c8c0 TH |
1945 | /** |
1946 | * blk_start_request - start request processing on the driver | |
1947 | * @req: request to dequeue | |
1948 | * | |
1949 | * Description: | |
1950 | * Dequeue @req and start timeout timer on it. This hands off the | |
1951 | * request to the driver. | |
1952 | * | |
1953 | * Block internal functions which don't want to start timer should | |
1954 | * call blk_dequeue_request(). | |
1955 | * | |
1956 | * Context: | |
1957 | * queue_lock must be held. | |
1958 | */ | |
1959 | void blk_start_request(struct request *req) | |
1960 | { | |
1961 | blk_dequeue_request(req); | |
1962 | ||
1963 | /* | |
5f49f631 TH |
1964 | * We are now handing the request to the hardware, initialize |
1965 | * resid_len to full count and add the timeout handler. | |
9934c8c0 | 1966 | */ |
5f49f631 | 1967 | req->resid_len = blk_rq_bytes(req); |
dbb66c4b FT |
1968 | if (unlikely(blk_bidi_rq(req))) |
1969 | req->next_rq->resid_len = blk_rq_bytes(req->next_rq); | |
1970 | ||
9934c8c0 TH |
1971 | blk_add_timer(req); |
1972 | } | |
1973 | EXPORT_SYMBOL(blk_start_request); | |
1974 | ||
1975 | /** | |
1976 | * blk_fetch_request - fetch a request from a request queue | |
1977 | * @q: request queue to fetch a request from | |
1978 | * | |
1979 | * Description: | |
1980 | * Return the request at the top of @q. The request is started on | |
1981 | * return and LLD can start processing it immediately. | |
1982 | * | |
1983 | * Return: | |
1984 | * Pointer to the request at the top of @q if available. Null | |
1985 | * otherwise. | |
1986 | * | |
1987 | * Context: | |
1988 | * queue_lock must be held. | |
1989 | */ | |
1990 | struct request *blk_fetch_request(struct request_queue *q) | |
1991 | { | |
1992 | struct request *rq; | |
1993 | ||
1994 | rq = blk_peek_request(q); | |
1995 | if (rq) | |
1996 | blk_start_request(rq); | |
1997 | return rq; | |
1998 | } | |
1999 | EXPORT_SYMBOL(blk_fetch_request); | |
2000 | ||
3bcddeac | 2001 | /** |
2e60e022 | 2002 | * blk_update_request - Special helper function for request stacking drivers |
8ebf9756 | 2003 | * @req: the request being processed |
710027a4 | 2004 | * @error: %0 for success, < %0 for error |
8ebf9756 | 2005 | * @nr_bytes: number of bytes to complete @req |
3bcddeac KU |
2006 | * |
2007 | * Description: | |
8ebf9756 RD |
2008 | * Ends I/O on a number of bytes attached to @req, but doesn't complete |
2009 | * the request structure even if @req doesn't have leftover. | |
2010 | * If @req has leftover, sets it up for the next range of segments. | |
2e60e022 TH |
2011 | * |
2012 | * This special helper function is only for request stacking drivers | |
2013 | * (e.g. request-based dm) so that they can handle partial completion. | |
2014 | * Actual device drivers should use blk_end_request instead. | |
2015 | * | |
2016 | * Passing the result of blk_rq_bytes() as @nr_bytes guarantees | |
2017 | * %false return from this function. | |
3bcddeac KU |
2018 | * |
2019 | * Return: | |
2e60e022 TH |
2020 | * %false - this request doesn't have any more data |
2021 | * %true - this request has more data | |
3bcddeac | 2022 | **/ |
2e60e022 | 2023 | bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) |
1da177e4 | 2024 | { |
5450d3e1 | 2025 | int total_bytes, bio_nbytes, next_idx = 0; |
1da177e4 LT |
2026 | struct bio *bio; |
2027 | ||
2e60e022 TH |
2028 | if (!req->bio) |
2029 | return false; | |
2030 | ||
5f3ea37c | 2031 | trace_block_rq_complete(req->q, req); |
2056a782 | 2032 | |
1da177e4 | 2033 | /* |
6f41469c TH |
2034 | * For fs requests, rq is just carrier of independent bio's |
2035 | * and each partial completion should be handled separately. | |
2036 | * Reset per-request error on each partial completion. | |
2037 | * | |
2038 | * TODO: tj: This is too subtle. It would be better to let | |
2039 | * low level drivers do what they see fit. | |
1da177e4 | 2040 | */ |
33659ebb | 2041 | if (req->cmd_type == REQ_TYPE_FS) |
1da177e4 LT |
2042 | req->errors = 0; |
2043 | ||
33659ebb CH |
2044 | if (error && req->cmd_type == REQ_TYPE_FS && |
2045 | !(req->cmd_flags & REQ_QUIET)) { | |
6728cb0e | 2046 | printk(KERN_ERR "end_request: I/O error, dev %s, sector %llu\n", |
1da177e4 | 2047 | req->rq_disk ? req->rq_disk->disk_name : "?", |
83096ebf | 2048 | (unsigned long long)blk_rq_pos(req)); |
1da177e4 LT |
2049 | } |
2050 | ||
bc58ba94 | 2051 | blk_account_io_completion(req, nr_bytes); |
d72d904a | 2052 | |
1da177e4 LT |
2053 | total_bytes = bio_nbytes = 0; |
2054 | while ((bio = req->bio) != NULL) { | |
2055 | int nbytes; | |
2056 | ||
2057 | if (nr_bytes >= bio->bi_size) { | |
2058 | req->bio = bio->bi_next; | |
2059 | nbytes = bio->bi_size; | |
5bb23a68 | 2060 | req_bio_endio(req, bio, nbytes, error); |
1da177e4 LT |
2061 | next_idx = 0; |
2062 | bio_nbytes = 0; | |
2063 | } else { | |
2064 | int idx = bio->bi_idx + next_idx; | |
2065 | ||
af498d7f | 2066 | if (unlikely(idx >= bio->bi_vcnt)) { |
1da177e4 | 2067 | blk_dump_rq_flags(req, "__end_that"); |
6728cb0e | 2068 | printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n", |
af498d7f | 2069 | __func__, idx, bio->bi_vcnt); |
1da177e4 LT |
2070 | break; |
2071 | } | |
2072 | ||
2073 | nbytes = bio_iovec_idx(bio, idx)->bv_len; | |
2074 | BIO_BUG_ON(nbytes > bio->bi_size); | |
2075 | ||
2076 | /* | |
2077 | * not a complete bvec done | |
2078 | */ | |
2079 | if (unlikely(nbytes > nr_bytes)) { | |
2080 | bio_nbytes += nr_bytes; | |
2081 | total_bytes += nr_bytes; | |
2082 | break; | |
2083 | } | |
2084 | ||
2085 | /* | |
2086 | * advance to the next vector | |
2087 | */ | |
2088 | next_idx++; | |
2089 | bio_nbytes += nbytes; | |
2090 | } | |
2091 | ||
2092 | total_bytes += nbytes; | |
2093 | nr_bytes -= nbytes; | |
2094 | ||
6728cb0e JA |
2095 | bio = req->bio; |
2096 | if (bio) { | |
1da177e4 LT |
2097 | /* |
2098 | * end more in this run, or just return 'not-done' | |
2099 | */ | |
2100 | if (unlikely(nr_bytes <= 0)) | |
2101 | break; | |
2102 | } | |
2103 | } | |
2104 | ||
2105 | /* | |
2106 | * completely done | |
2107 | */ | |
2e60e022 TH |
2108 | if (!req->bio) { |
2109 | /* | |
2110 | * Reset counters so that the request stacking driver | |
2111 | * can find how many bytes remain in the request | |
2112 | * later. | |
2113 | */ | |
a2dec7b3 | 2114 | req->__data_len = 0; |
2e60e022 TH |
2115 | return false; |
2116 | } | |
1da177e4 LT |
2117 | |
2118 | /* | |
2119 | * if the request wasn't completed, update state | |
2120 | */ | |
2121 | if (bio_nbytes) { | |
5bb23a68 | 2122 | req_bio_endio(req, bio, bio_nbytes, error); |
1da177e4 LT |
2123 | bio->bi_idx += next_idx; |
2124 | bio_iovec(bio)->bv_offset += nr_bytes; | |
2125 | bio_iovec(bio)->bv_len -= nr_bytes; | |
2126 | } | |
2127 | ||
a2dec7b3 | 2128 | req->__data_len -= total_bytes; |
2e46e8b2 TH |
2129 | req->buffer = bio_data(req->bio); |
2130 | ||
2131 | /* update sector only for requests with clear definition of sector */ | |
33659ebb | 2132 | if (req->cmd_type == REQ_TYPE_FS || (req->cmd_flags & REQ_DISCARD)) |
a2dec7b3 | 2133 | req->__sector += total_bytes >> 9; |
2e46e8b2 | 2134 | |
80a761fd TH |
2135 | /* mixed attributes always follow the first bio */ |
2136 | if (req->cmd_flags & REQ_MIXED_MERGE) { | |
2137 | req->cmd_flags &= ~REQ_FAILFAST_MASK; | |
2138 | req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK; | |
2139 | } | |
2140 | ||
2e46e8b2 TH |
2141 | /* |
2142 | * If total number of sectors is less than the first segment | |
2143 | * size, something has gone terribly wrong. | |
2144 | */ | |
2145 | if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { | |
2146 | printk(KERN_ERR "blk: request botched\n"); | |
a2dec7b3 | 2147 | req->__data_len = blk_rq_cur_bytes(req); |
2e46e8b2 TH |
2148 | } |
2149 | ||
2150 | /* recalculate the number of segments */ | |
1da177e4 | 2151 | blk_recalc_rq_segments(req); |
2e46e8b2 | 2152 | |
2e60e022 | 2153 | return true; |
1da177e4 | 2154 | } |
2e60e022 | 2155 | EXPORT_SYMBOL_GPL(blk_update_request); |
1da177e4 | 2156 | |
2e60e022 TH |
2157 | static bool blk_update_bidi_request(struct request *rq, int error, |
2158 | unsigned int nr_bytes, | |
2159 | unsigned int bidi_bytes) | |
5efccd17 | 2160 | { |
2e60e022 TH |
2161 | if (blk_update_request(rq, error, nr_bytes)) |
2162 | return true; | |
5efccd17 | 2163 | |
2e60e022 TH |
2164 | /* Bidi request must be completed as a whole */ |
2165 | if (unlikely(blk_bidi_rq(rq)) && | |
2166 | blk_update_request(rq->next_rq, error, bidi_bytes)) | |
2167 | return true; | |
5efccd17 | 2168 | |
e2e1a148 JA |
2169 | if (blk_queue_add_random(rq->q)) |
2170 | add_disk_randomness(rq->rq_disk); | |
2e60e022 TH |
2171 | |
2172 | return false; | |
1da177e4 LT |
2173 | } |
2174 | ||
28018c24 JB |
2175 | /** |
2176 | * blk_unprep_request - unprepare a request | |
2177 | * @req: the request | |
2178 | * | |
2179 | * This function makes a request ready for complete resubmission (or | |
2180 | * completion). It happens only after all error handling is complete, | |
2181 | * so represents the appropriate moment to deallocate any resources | |
2182 | * that were allocated to the request in the prep_rq_fn. The queue | |
2183 | * lock is held when calling this. | |
2184 | */ | |
2185 | void blk_unprep_request(struct request *req) | |
2186 | { | |
2187 | struct request_queue *q = req->q; | |
2188 | ||
2189 | req->cmd_flags &= ~REQ_DONTPREP; | |
2190 | if (q->unprep_rq_fn) | |
2191 | q->unprep_rq_fn(q, req); | |
2192 | } | |
2193 | EXPORT_SYMBOL_GPL(blk_unprep_request); | |
2194 | ||
1da177e4 LT |
2195 | /* |
2196 | * queue lock must be held | |
2197 | */ | |
2e60e022 | 2198 | static void blk_finish_request(struct request *req, int error) |
1da177e4 | 2199 | { |
b8286239 KU |
2200 | if (blk_rq_tagged(req)) |
2201 | blk_queue_end_tag(req->q, req); | |
2202 | ||
ba396a6c | 2203 | BUG_ON(blk_queued_rq(req)); |
1da177e4 | 2204 | |
33659ebb | 2205 | if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS) |
31373d09 | 2206 | laptop_io_completion(&req->q->backing_dev_info); |
1da177e4 | 2207 | |
e78042e5 MA |
2208 | blk_delete_timer(req); |
2209 | ||
28018c24 JB |
2210 | if (req->cmd_flags & REQ_DONTPREP) |
2211 | blk_unprep_request(req); | |
2212 | ||
2213 | ||
bc58ba94 | 2214 | blk_account_io_done(req); |
b8286239 | 2215 | |
1da177e4 | 2216 | if (req->end_io) |
8ffdc655 | 2217 | req->end_io(req, error); |
b8286239 KU |
2218 | else { |
2219 | if (blk_bidi_rq(req)) | |
2220 | __blk_put_request(req->next_rq->q, req->next_rq); | |
2221 | ||
1da177e4 | 2222 | __blk_put_request(req->q, req); |
b8286239 | 2223 | } |
1da177e4 LT |
2224 | } |
2225 | ||
3b11313a | 2226 | /** |
2e60e022 TH |
2227 | * blk_end_bidi_request - Complete a bidi request |
2228 | * @rq: the request to complete | |
2229 | * @error: %0 for success, < %0 for error | |
2230 | * @nr_bytes: number of bytes to complete @rq | |
2231 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
a0cd1285 JA |
2232 | * |
2233 | * Description: | |
e3a04fe3 | 2234 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
2e60e022 TH |
2235 | * Drivers that supports bidi can safely call this member for any |
2236 | * type of request, bidi or uni. In the later case @bidi_bytes is | |
2237 | * just ignored. | |
336cdb40 KU |
2238 | * |
2239 | * Return: | |
2e60e022 TH |
2240 | * %false - we are done with this request |
2241 | * %true - still buffers pending for this request | |
a0cd1285 | 2242 | **/ |
b1f74493 | 2243 | static bool blk_end_bidi_request(struct request *rq, int error, |
32fab448 KU |
2244 | unsigned int nr_bytes, unsigned int bidi_bytes) |
2245 | { | |
336cdb40 | 2246 | struct request_queue *q = rq->q; |
2e60e022 | 2247 | unsigned long flags; |
32fab448 | 2248 | |
2e60e022 TH |
2249 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
2250 | return true; | |
32fab448 | 2251 | |
336cdb40 | 2252 | spin_lock_irqsave(q->queue_lock, flags); |
2e60e022 | 2253 | blk_finish_request(rq, error); |
336cdb40 KU |
2254 | spin_unlock_irqrestore(q->queue_lock, flags); |
2255 | ||
2e60e022 | 2256 | return false; |
32fab448 KU |
2257 | } |
2258 | ||
336cdb40 | 2259 | /** |
2e60e022 TH |
2260 | * __blk_end_bidi_request - Complete a bidi request with queue lock held |
2261 | * @rq: the request to complete | |
710027a4 | 2262 | * @error: %0 for success, < %0 for error |
e3a04fe3 KU |
2263 | * @nr_bytes: number of bytes to complete @rq |
2264 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
336cdb40 KU |
2265 | * |
2266 | * Description: | |
2e60e022 TH |
2267 | * Identical to blk_end_bidi_request() except that queue lock is |
2268 | * assumed to be locked on entry and remains so on return. | |
336cdb40 KU |
2269 | * |
2270 | * Return: | |
2e60e022 TH |
2271 | * %false - we are done with this request |
2272 | * %true - still buffers pending for this request | |
336cdb40 | 2273 | **/ |
b1f74493 FT |
2274 | static bool __blk_end_bidi_request(struct request *rq, int error, |
2275 | unsigned int nr_bytes, unsigned int bidi_bytes) | |
336cdb40 | 2276 | { |
2e60e022 TH |
2277 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
2278 | return true; | |
336cdb40 | 2279 | |
2e60e022 | 2280 | blk_finish_request(rq, error); |
336cdb40 | 2281 | |
2e60e022 | 2282 | return false; |
336cdb40 | 2283 | } |
e19a3ab0 KU |
2284 | |
2285 | /** | |
2286 | * blk_end_request - Helper function for drivers to complete the request. | |
2287 | * @rq: the request being processed | |
710027a4 | 2288 | * @error: %0 for success, < %0 for error |
e19a3ab0 KU |
2289 | * @nr_bytes: number of bytes to complete |
2290 | * | |
2291 | * Description: | |
2292 | * Ends I/O on a number of bytes attached to @rq. | |
2293 | * If @rq has leftover, sets it up for the next range of segments. | |
2294 | * | |
2295 | * Return: | |
b1f74493 FT |
2296 | * %false - we are done with this request |
2297 | * %true - still buffers pending for this request | |
e19a3ab0 | 2298 | **/ |
b1f74493 | 2299 | bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
e19a3ab0 | 2300 | { |
b1f74493 | 2301 | return blk_end_bidi_request(rq, error, nr_bytes, 0); |
e19a3ab0 | 2302 | } |
56ad1740 | 2303 | EXPORT_SYMBOL(blk_end_request); |
336cdb40 KU |
2304 | |
2305 | /** | |
b1f74493 FT |
2306 | * blk_end_request_all - Helper function for drives to finish the request. |
2307 | * @rq: the request to finish | |
8ebf9756 | 2308 | * @error: %0 for success, < %0 for error |
336cdb40 KU |
2309 | * |
2310 | * Description: | |
b1f74493 FT |
2311 | * Completely finish @rq. |
2312 | */ | |
2313 | void blk_end_request_all(struct request *rq, int error) | |
336cdb40 | 2314 | { |
b1f74493 FT |
2315 | bool pending; |
2316 | unsigned int bidi_bytes = 0; | |
336cdb40 | 2317 | |
b1f74493 FT |
2318 | if (unlikely(blk_bidi_rq(rq))) |
2319 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
336cdb40 | 2320 | |
b1f74493 FT |
2321 | pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); |
2322 | BUG_ON(pending); | |
2323 | } | |
56ad1740 | 2324 | EXPORT_SYMBOL(blk_end_request_all); |
336cdb40 | 2325 | |
b1f74493 FT |
2326 | /** |
2327 | * blk_end_request_cur - Helper function to finish the current request chunk. | |
2328 | * @rq: the request to finish the current chunk for | |
8ebf9756 | 2329 | * @error: %0 for success, < %0 for error |
b1f74493 FT |
2330 | * |
2331 | * Description: | |
2332 | * Complete the current consecutively mapped chunk from @rq. | |
2333 | * | |
2334 | * Return: | |
2335 | * %false - we are done with this request | |
2336 | * %true - still buffers pending for this request | |
2337 | */ | |
2338 | bool blk_end_request_cur(struct request *rq, int error) | |
2339 | { | |
2340 | return blk_end_request(rq, error, blk_rq_cur_bytes(rq)); | |
336cdb40 | 2341 | } |
56ad1740 | 2342 | EXPORT_SYMBOL(blk_end_request_cur); |
336cdb40 | 2343 | |
80a761fd TH |
2344 | /** |
2345 | * blk_end_request_err - Finish a request till the next failure boundary. | |
2346 | * @rq: the request to finish till the next failure boundary for | |
2347 | * @error: must be negative errno | |
2348 | * | |
2349 | * Description: | |
2350 | * Complete @rq till the next failure boundary. | |
2351 | * | |
2352 | * Return: | |
2353 | * %false - we are done with this request | |
2354 | * %true - still buffers pending for this request | |
2355 | */ | |
2356 | bool blk_end_request_err(struct request *rq, int error) | |
2357 | { | |
2358 | WARN_ON(error >= 0); | |
2359 | return blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2360 | } | |
2361 | EXPORT_SYMBOL_GPL(blk_end_request_err); | |
2362 | ||
e3a04fe3 | 2363 | /** |
b1f74493 FT |
2364 | * __blk_end_request - Helper function for drivers to complete the request. |
2365 | * @rq: the request being processed | |
2366 | * @error: %0 for success, < %0 for error | |
2367 | * @nr_bytes: number of bytes to complete | |
e3a04fe3 KU |
2368 | * |
2369 | * Description: | |
b1f74493 | 2370 | * Must be called with queue lock held unlike blk_end_request(). |
e3a04fe3 KU |
2371 | * |
2372 | * Return: | |
b1f74493 FT |
2373 | * %false - we are done with this request |
2374 | * %true - still buffers pending for this request | |
e3a04fe3 | 2375 | **/ |
b1f74493 | 2376 | bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
e3a04fe3 | 2377 | { |
b1f74493 | 2378 | return __blk_end_bidi_request(rq, error, nr_bytes, 0); |
e3a04fe3 | 2379 | } |
56ad1740 | 2380 | EXPORT_SYMBOL(__blk_end_request); |
e3a04fe3 | 2381 | |
32fab448 | 2382 | /** |
b1f74493 FT |
2383 | * __blk_end_request_all - Helper function for drives to finish the request. |
2384 | * @rq: the request to finish | |
8ebf9756 | 2385 | * @error: %0 for success, < %0 for error |
32fab448 KU |
2386 | * |
2387 | * Description: | |
b1f74493 | 2388 | * Completely finish @rq. Must be called with queue lock held. |
32fab448 | 2389 | */ |
b1f74493 | 2390 | void __blk_end_request_all(struct request *rq, int error) |
32fab448 | 2391 | { |
b1f74493 FT |
2392 | bool pending; |
2393 | unsigned int bidi_bytes = 0; | |
2394 | ||
2395 | if (unlikely(blk_bidi_rq(rq))) | |
2396 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
2397 | ||
2398 | pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
2399 | BUG_ON(pending); | |
32fab448 | 2400 | } |
56ad1740 | 2401 | EXPORT_SYMBOL(__blk_end_request_all); |
32fab448 | 2402 | |
e19a3ab0 | 2403 | /** |
b1f74493 FT |
2404 | * __blk_end_request_cur - Helper function to finish the current request chunk. |
2405 | * @rq: the request to finish the current chunk for | |
8ebf9756 | 2406 | * @error: %0 for success, < %0 for error |
e19a3ab0 KU |
2407 | * |
2408 | * Description: | |
b1f74493 FT |
2409 | * Complete the current consecutively mapped chunk from @rq. Must |
2410 | * be called with queue lock held. | |
e19a3ab0 KU |
2411 | * |
2412 | * Return: | |
b1f74493 FT |
2413 | * %false - we are done with this request |
2414 | * %true - still buffers pending for this request | |
2415 | */ | |
2416 | bool __blk_end_request_cur(struct request *rq, int error) | |
e19a3ab0 | 2417 | { |
b1f74493 | 2418 | return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); |
e19a3ab0 | 2419 | } |
56ad1740 | 2420 | EXPORT_SYMBOL(__blk_end_request_cur); |
e19a3ab0 | 2421 | |
80a761fd TH |
2422 | /** |
2423 | * __blk_end_request_err - Finish a request till the next failure boundary. | |
2424 | * @rq: the request to finish till the next failure boundary for | |
2425 | * @error: must be negative errno | |
2426 | * | |
2427 | * Description: | |
2428 | * Complete @rq till the next failure boundary. Must be called | |
2429 | * with queue lock held. | |
2430 | * | |
2431 | * Return: | |
2432 | * %false - we are done with this request | |
2433 | * %true - still buffers pending for this request | |
2434 | */ | |
2435 | bool __blk_end_request_err(struct request *rq, int error) | |
2436 | { | |
2437 | WARN_ON(error >= 0); | |
2438 | return __blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2439 | } | |
2440 | EXPORT_SYMBOL_GPL(__blk_end_request_err); | |
2441 | ||
86db1e29 JA |
2442 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
2443 | struct bio *bio) | |
1da177e4 | 2444 | { |
a82afdfc | 2445 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */ |
7b6d91da | 2446 | rq->cmd_flags |= bio->bi_rw & REQ_WRITE; |
1da177e4 | 2447 | |
fb2dce86 DW |
2448 | if (bio_has_data(bio)) { |
2449 | rq->nr_phys_segments = bio_phys_segments(q, bio); | |
fb2dce86 DW |
2450 | rq->buffer = bio_data(bio); |
2451 | } | |
a2dec7b3 | 2452 | rq->__data_len = bio->bi_size; |
1da177e4 | 2453 | rq->bio = rq->biotail = bio; |
1da177e4 | 2454 | |
66846572 N |
2455 | if (bio->bi_bdev) |
2456 | rq->rq_disk = bio->bi_bdev->bd_disk; | |
2457 | } | |
1da177e4 | 2458 | |
2d4dc890 IL |
2459 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
2460 | /** | |
2461 | * rq_flush_dcache_pages - Helper function to flush all pages in a request | |
2462 | * @rq: the request to be flushed | |
2463 | * | |
2464 | * Description: | |
2465 | * Flush all pages in @rq. | |
2466 | */ | |
2467 | void rq_flush_dcache_pages(struct request *rq) | |
2468 | { | |
2469 | struct req_iterator iter; | |
2470 | struct bio_vec *bvec; | |
2471 | ||
2472 | rq_for_each_segment(bvec, rq, iter) | |
2473 | flush_dcache_page(bvec->bv_page); | |
2474 | } | |
2475 | EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); | |
2476 | #endif | |
2477 | ||
ef9e3fac KU |
2478 | /** |
2479 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy | |
2480 | * @q : the queue of the device being checked | |
2481 | * | |
2482 | * Description: | |
2483 | * Check if underlying low-level drivers of a device are busy. | |
2484 | * If the drivers want to export their busy state, they must set own | |
2485 | * exporting function using blk_queue_lld_busy() first. | |
2486 | * | |
2487 | * Basically, this function is used only by request stacking drivers | |
2488 | * to stop dispatching requests to underlying devices when underlying | |
2489 | * devices are busy. This behavior helps more I/O merging on the queue | |
2490 | * of the request stacking driver and prevents I/O throughput regression | |
2491 | * on burst I/O load. | |
2492 | * | |
2493 | * Return: | |
2494 | * 0 - Not busy (The request stacking driver should dispatch request) | |
2495 | * 1 - Busy (The request stacking driver should stop dispatching request) | |
2496 | */ | |
2497 | int blk_lld_busy(struct request_queue *q) | |
2498 | { | |
2499 | if (q->lld_busy_fn) | |
2500 | return q->lld_busy_fn(q); | |
2501 | ||
2502 | return 0; | |
2503 | } | |
2504 | EXPORT_SYMBOL_GPL(blk_lld_busy); | |
2505 | ||
b0fd271d KU |
2506 | /** |
2507 | * blk_rq_unprep_clone - Helper function to free all bios in a cloned request | |
2508 | * @rq: the clone request to be cleaned up | |
2509 | * | |
2510 | * Description: | |
2511 | * Free all bios in @rq for a cloned request. | |
2512 | */ | |
2513 | void blk_rq_unprep_clone(struct request *rq) | |
2514 | { | |
2515 | struct bio *bio; | |
2516 | ||
2517 | while ((bio = rq->bio) != NULL) { | |
2518 | rq->bio = bio->bi_next; | |
2519 | ||
2520 | bio_put(bio); | |
2521 | } | |
2522 | } | |
2523 | EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); | |
2524 | ||
2525 | /* | |
2526 | * Copy attributes of the original request to the clone request. | |
2527 | * The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not copied. | |
2528 | */ | |
2529 | static void __blk_rq_prep_clone(struct request *dst, struct request *src) | |
2530 | { | |
2531 | dst->cpu = src->cpu; | |
3a2edd0d | 2532 | dst->cmd_flags = (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; |
b0fd271d KU |
2533 | dst->cmd_type = src->cmd_type; |
2534 | dst->__sector = blk_rq_pos(src); | |
2535 | dst->__data_len = blk_rq_bytes(src); | |
2536 | dst->nr_phys_segments = src->nr_phys_segments; | |
2537 | dst->ioprio = src->ioprio; | |
2538 | dst->extra_len = src->extra_len; | |
2539 | } | |
2540 | ||
2541 | /** | |
2542 | * blk_rq_prep_clone - Helper function to setup clone request | |
2543 | * @rq: the request to be setup | |
2544 | * @rq_src: original request to be cloned | |
2545 | * @bs: bio_set that bios for clone are allocated from | |
2546 | * @gfp_mask: memory allocation mask for bio | |
2547 | * @bio_ctr: setup function to be called for each clone bio. | |
2548 | * Returns %0 for success, non %0 for failure. | |
2549 | * @data: private data to be passed to @bio_ctr | |
2550 | * | |
2551 | * Description: | |
2552 | * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. | |
2553 | * The actual data parts of @rq_src (e.g. ->cmd, ->buffer, ->sense) | |
2554 | * are not copied, and copying such parts is the caller's responsibility. | |
2555 | * Also, pages which the original bios are pointing to are not copied | |
2556 | * and the cloned bios just point same pages. | |
2557 | * So cloned bios must be completed before original bios, which means | |
2558 | * the caller must complete @rq before @rq_src. | |
2559 | */ | |
2560 | int blk_rq_prep_clone(struct request *rq, struct request *rq_src, | |
2561 | struct bio_set *bs, gfp_t gfp_mask, | |
2562 | int (*bio_ctr)(struct bio *, struct bio *, void *), | |
2563 | void *data) | |
2564 | { | |
2565 | struct bio *bio, *bio_src; | |
2566 | ||
2567 | if (!bs) | |
2568 | bs = fs_bio_set; | |
2569 | ||
2570 | blk_rq_init(NULL, rq); | |
2571 | ||
2572 | __rq_for_each_bio(bio_src, rq_src) { | |
2573 | bio = bio_alloc_bioset(gfp_mask, bio_src->bi_max_vecs, bs); | |
2574 | if (!bio) | |
2575 | goto free_and_out; | |
2576 | ||
2577 | __bio_clone(bio, bio_src); | |
2578 | ||
2579 | if (bio_integrity(bio_src) && | |
7878cba9 | 2580 | bio_integrity_clone(bio, bio_src, gfp_mask, bs)) |
b0fd271d KU |
2581 | goto free_and_out; |
2582 | ||
2583 | if (bio_ctr && bio_ctr(bio, bio_src, data)) | |
2584 | goto free_and_out; | |
2585 | ||
2586 | if (rq->bio) { | |
2587 | rq->biotail->bi_next = bio; | |
2588 | rq->biotail = bio; | |
2589 | } else | |
2590 | rq->bio = rq->biotail = bio; | |
2591 | } | |
2592 | ||
2593 | __blk_rq_prep_clone(rq, rq_src); | |
2594 | ||
2595 | return 0; | |
2596 | ||
2597 | free_and_out: | |
2598 | if (bio) | |
2599 | bio_free(bio, bs); | |
2600 | blk_rq_unprep_clone(rq); | |
2601 | ||
2602 | return -ENOMEM; | |
2603 | } | |
2604 | EXPORT_SYMBOL_GPL(blk_rq_prep_clone); | |
2605 | ||
18887ad9 | 2606 | int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) |
1da177e4 LT |
2607 | { |
2608 | return queue_work(kblockd_workqueue, work); | |
2609 | } | |
1da177e4 LT |
2610 | EXPORT_SYMBOL(kblockd_schedule_work); |
2611 | ||
e43473b7 VG |
2612 | int kblockd_schedule_delayed_work(struct request_queue *q, |
2613 | struct delayed_work *dwork, unsigned long delay) | |
2614 | { | |
2615 | return queue_delayed_work(kblockd_workqueue, dwork, delay); | |
2616 | } | |
2617 | EXPORT_SYMBOL(kblockd_schedule_delayed_work); | |
2618 | ||
1da177e4 LT |
2619 | int __init blk_dev_init(void) |
2620 | { | |
9eb55b03 NK |
2621 | BUILD_BUG_ON(__REQ_NR_BITS > 8 * |
2622 | sizeof(((struct request *)0)->cmd_flags)); | |
2623 | ||
1da177e4 LT |
2624 | kblockd_workqueue = create_workqueue("kblockd"); |
2625 | if (!kblockd_workqueue) | |
2626 | panic("Failed to create kblockd\n"); | |
2627 | ||
2628 | request_cachep = kmem_cache_create("blkdev_requests", | |
20c2df83 | 2629 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
1da177e4 | 2630 | |
8324aa91 | 2631 | blk_requestq_cachep = kmem_cache_create("blkdev_queue", |
165125e1 | 2632 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
1da177e4 | 2633 | |
d38ecf93 | 2634 | return 0; |
1da177e4 | 2635 | } |