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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Block device elevator/IO-scheduler. |
3 | * | |
4 | * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE | |
5 | * | |
0fe23479 | 6 | * 30042000 Jens Axboe <axboe@kernel.dk> : |
1da177e4 LT |
7 | * |
8 | * Split the elevator a bit so that it is possible to choose a different | |
9 | * one or even write a new "plug in". There are three pieces: | |
10 | * - elevator_fn, inserts a new request in the queue list | |
11 | * - elevator_merge_fn, decides whether a new buffer can be merged with | |
12 | * an existing request | |
13 | * - elevator_dequeue_fn, called when a request is taken off the active list | |
14 | * | |
15 | * 20082000 Dave Jones <davej@suse.de> : | |
16 | * Removed tests for max-bomb-segments, which was breaking elvtune | |
17 | * when run without -bN | |
18 | * | |
19 | * Jens: | |
20 | * - Rework again to work with bio instead of buffer_heads | |
21 | * - loose bi_dev comparisons, partition handling is right now | |
22 | * - completely modularize elevator setup and teardown | |
23 | * | |
24 | */ | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/fs.h> | |
27 | #include <linux/blkdev.h> | |
28 | #include <linux/elevator.h> | |
29 | #include <linux/bio.h> | |
1da177e4 LT |
30 | #include <linux/module.h> |
31 | #include <linux/slab.h> | |
32 | #include <linux/init.h> | |
33 | #include <linux/compiler.h> | |
2056a782 | 34 | #include <linux/blktrace_api.h> |
9817064b | 35 | #include <linux/hash.h> |
0835da67 | 36 | #include <linux/uaccess.h> |
c8158819 | 37 | #include <linux/pm_runtime.h> |
eea8f41c | 38 | #include <linux/blk-cgroup.h> |
1da177e4 | 39 | |
55782138 LZ |
40 | #include <trace/events/block.h> |
41 | ||
242f9dcb | 42 | #include "blk.h" |
bd166ef1 | 43 | #include "blk-mq-sched.h" |
242f9dcb | 44 | |
1da177e4 LT |
45 | static DEFINE_SPINLOCK(elv_list_lock); |
46 | static LIST_HEAD(elv_list); | |
47 | ||
9817064b JA |
48 | /* |
49 | * Merge hash stuff. | |
50 | */ | |
83096ebf | 51 | #define rq_hash_key(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
9817064b | 52 | |
da775265 JA |
53 | /* |
54 | * Query io scheduler to see if the current process issuing bio may be | |
55 | * merged with rq. | |
56 | */ | |
72ef799b | 57 | static int elv_iosched_allow_bio_merge(struct request *rq, struct bio *bio) |
da775265 | 58 | { |
165125e1 | 59 | struct request_queue *q = rq->q; |
b374d18a | 60 | struct elevator_queue *e = q->elevator; |
da775265 | 61 | |
bd166ef1 JA |
62 | if (e->uses_mq && e->type->ops.mq.allow_merge) |
63 | return e->type->ops.mq.allow_merge(q, rq, bio); | |
64 | else if (!e->uses_mq && e->type->ops.sq.elevator_allow_bio_merge_fn) | |
c51ca6cf | 65 | return e->type->ops.sq.elevator_allow_bio_merge_fn(q, rq, bio); |
da775265 JA |
66 | |
67 | return 1; | |
68 | } | |
69 | ||
1da177e4 LT |
70 | /* |
71 | * can we safely merge with this request? | |
72 | */ | |
72ef799b | 73 | bool elv_bio_merge_ok(struct request *rq, struct bio *bio) |
1da177e4 | 74 | { |
050c8ea8 | 75 | if (!blk_rq_merge_ok(rq, bio)) |
72ef799b | 76 | return false; |
7ba1ba12 | 77 | |
72ef799b TE |
78 | if (!elv_iosched_allow_bio_merge(rq, bio)) |
79 | return false; | |
1da177e4 | 80 | |
72ef799b | 81 | return true; |
1da177e4 | 82 | } |
72ef799b | 83 | EXPORT_SYMBOL(elv_bio_merge_ok); |
1da177e4 | 84 | |
1da177e4 LT |
85 | static struct elevator_type *elevator_find(const char *name) |
86 | { | |
a22b169d | 87 | struct elevator_type *e; |
1da177e4 | 88 | |
70cee26e | 89 | list_for_each_entry(e, &elv_list, list) { |
a22b169d VT |
90 | if (!strcmp(e->elevator_name, name)) |
91 | return e; | |
1da177e4 | 92 | } |
1da177e4 | 93 | |
a22b169d | 94 | return NULL; |
1da177e4 LT |
95 | } |
96 | ||
97 | static void elevator_put(struct elevator_type *e) | |
98 | { | |
99 | module_put(e->elevator_owner); | |
100 | } | |
101 | ||
21c3c5d2 | 102 | static struct elevator_type *elevator_get(const char *name, bool try_loading) |
1da177e4 | 103 | { |
2824bc93 | 104 | struct elevator_type *e; |
1da177e4 | 105 | |
2a12dcd7 | 106 | spin_lock(&elv_list_lock); |
2824bc93 TH |
107 | |
108 | e = elevator_find(name); | |
21c3c5d2 | 109 | if (!e && try_loading) { |
e1640949 | 110 | spin_unlock(&elv_list_lock); |
490b94be | 111 | request_module("%s-iosched", name); |
e1640949 JA |
112 | spin_lock(&elv_list_lock); |
113 | e = elevator_find(name); | |
114 | } | |
115 | ||
2824bc93 TH |
116 | if (e && !try_module_get(e->elevator_owner)) |
117 | e = NULL; | |
118 | ||
2a12dcd7 | 119 | spin_unlock(&elv_list_lock); |
1da177e4 LT |
120 | |
121 | return e; | |
122 | } | |
123 | ||
484fc254 | 124 | static char chosen_elevator[ELV_NAME_MAX]; |
1da177e4 | 125 | |
5f003976 | 126 | static int __init elevator_setup(char *str) |
1da177e4 | 127 | { |
752a3b79 CE |
128 | /* |
129 | * Be backwards-compatible with previous kernels, so users | |
130 | * won't get the wrong elevator. | |
131 | */ | |
492af635 | 132 | strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); |
9b41046c | 133 | return 1; |
1da177e4 LT |
134 | } |
135 | ||
136 | __setup("elevator=", elevator_setup); | |
137 | ||
bb813f4c TH |
138 | /* called during boot to load the elevator chosen by the elevator param */ |
139 | void __init load_default_elevator_module(void) | |
140 | { | |
141 | struct elevator_type *e; | |
142 | ||
143 | if (!chosen_elevator[0]) | |
144 | return; | |
145 | ||
146 | spin_lock(&elv_list_lock); | |
147 | e = elevator_find(chosen_elevator); | |
148 | spin_unlock(&elv_list_lock); | |
149 | ||
150 | if (!e) | |
151 | request_module("%s-iosched", chosen_elevator); | |
152 | } | |
153 | ||
3d1ab40f AV |
154 | static struct kobj_type elv_ktype; |
155 | ||
d50235b7 | 156 | struct elevator_queue *elevator_alloc(struct request_queue *q, |
165125e1 | 157 | struct elevator_type *e) |
3d1ab40f | 158 | { |
b374d18a | 159 | struct elevator_queue *eq; |
9817064b | 160 | |
c1b511eb | 161 | eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node); |
9817064b | 162 | if (unlikely(!eq)) |
8406a4d5 | 163 | return NULL; |
9817064b | 164 | |
22f746e2 | 165 | eq->type = e; |
f9cb074b | 166 | kobject_init(&eq->kobj, &elv_ktype); |
9817064b | 167 | mutex_init(&eq->sysfs_lock); |
242d98f0 | 168 | hash_init(eq->hash); |
bd166ef1 | 169 | eq->uses_mq = e->uses_mq; |
9817064b | 170 | |
3d1ab40f AV |
171 | return eq; |
172 | } | |
d50235b7 | 173 | EXPORT_SYMBOL(elevator_alloc); |
3d1ab40f AV |
174 | |
175 | static void elevator_release(struct kobject *kobj) | |
176 | { | |
b374d18a | 177 | struct elevator_queue *e; |
9817064b | 178 | |
b374d18a | 179 | e = container_of(kobj, struct elevator_queue, kobj); |
22f746e2 | 180 | elevator_put(e->type); |
3d1ab40f AV |
181 | kfree(e); |
182 | } | |
183 | ||
165125e1 | 184 | int elevator_init(struct request_queue *q, char *name) |
1da177e4 LT |
185 | { |
186 | struct elevator_type *e = NULL; | |
f8fc877d | 187 | int err; |
1da177e4 | 188 | |
eb1c160b TS |
189 | /* |
190 | * q->sysfs_lock must be held to provide mutual exclusion between | |
191 | * elevator_switch() and here. | |
192 | */ | |
193 | lockdep_assert_held(&q->sysfs_lock); | |
194 | ||
1abec4fd MS |
195 | if (unlikely(q->elevator)) |
196 | return 0; | |
197 | ||
cb98fc8b TH |
198 | INIT_LIST_HEAD(&q->queue_head); |
199 | q->last_merge = NULL; | |
200 | q->end_sector = 0; | |
201 | q->boundary_rq = NULL; | |
cb98fc8b | 202 | |
4eb166d9 | 203 | if (name) { |
21c3c5d2 | 204 | e = elevator_get(name, true); |
4eb166d9 JA |
205 | if (!e) |
206 | return -EINVAL; | |
207 | } | |
1da177e4 | 208 | |
21c3c5d2 TH |
209 | /* |
210 | * Use the default elevator specified by config boot param or | |
211 | * config option. Don't try to load modules as we could be running | |
212 | * off async and request_module() isn't allowed from async. | |
213 | */ | |
4eb166d9 | 214 | if (!e && *chosen_elevator) { |
21c3c5d2 | 215 | e = elevator_get(chosen_elevator, false); |
4eb166d9 JA |
216 | if (!e) |
217 | printk(KERN_ERR "I/O scheduler %s not found\n", | |
218 | chosen_elevator); | |
219 | } | |
248d5ca5 | 220 | |
4eb166d9 | 221 | if (!e) { |
d3484991 JA |
222 | if (q->mq_ops && q->nr_hw_queues == 1) |
223 | e = elevator_get(CONFIG_DEFAULT_SQ_IOSCHED, false); | |
224 | else if (q->mq_ops) | |
225 | e = elevator_get(CONFIG_DEFAULT_MQ_IOSCHED, false); | |
226 | else | |
227 | e = elevator_get(CONFIG_DEFAULT_IOSCHED, false); | |
228 | ||
4eb166d9 JA |
229 | if (!e) { |
230 | printk(KERN_ERR | |
231 | "Default I/O scheduler not found. " \ | |
bd166ef1 | 232 | "Using noop/none.\n"); |
21c3c5d2 | 233 | e = elevator_get("noop", false); |
4eb166d9 | 234 | } |
5f003976 ND |
235 | } |
236 | ||
bd166ef1 JA |
237 | if (e->uses_mq) { |
238 | err = blk_mq_sched_setup(q); | |
239 | if (!err) | |
240 | err = e->ops.mq.init_sched(q, e); | |
241 | } else | |
242 | err = e->ops.sq.elevator_init_fn(q, e); | |
243 | if (err) { | |
244 | if (e->uses_mq) | |
245 | blk_mq_sched_teardown(q); | |
d32f6b57 | 246 | elevator_put(e); |
bd166ef1 | 247 | } |
d32f6b57 | 248 | return err; |
1da177e4 | 249 | } |
2e662b65 JA |
250 | EXPORT_SYMBOL(elevator_init); |
251 | ||
b374d18a | 252 | void elevator_exit(struct elevator_queue *e) |
1da177e4 | 253 | { |
3d1ab40f | 254 | mutex_lock(&e->sysfs_lock); |
bd166ef1 JA |
255 | if (e->uses_mq && e->type->ops.mq.exit_sched) |
256 | e->type->ops.mq.exit_sched(e); | |
257 | else if (!e->uses_mq && e->type->ops.sq.elevator_exit_fn) | |
c51ca6cf | 258 | e->type->ops.sq.elevator_exit_fn(e); |
3d1ab40f | 259 | mutex_unlock(&e->sysfs_lock); |
1da177e4 | 260 | |
3d1ab40f | 261 | kobject_put(&e->kobj); |
1da177e4 | 262 | } |
2e662b65 JA |
263 | EXPORT_SYMBOL(elevator_exit); |
264 | ||
9817064b JA |
265 | static inline void __elv_rqhash_del(struct request *rq) |
266 | { | |
242d98f0 | 267 | hash_del(&rq->hash); |
e8064021 | 268 | rq->rq_flags &= ~RQF_HASHED; |
9817064b JA |
269 | } |
270 | ||
70b3ea05 | 271 | void elv_rqhash_del(struct request_queue *q, struct request *rq) |
9817064b JA |
272 | { |
273 | if (ELV_ON_HASH(rq)) | |
274 | __elv_rqhash_del(rq); | |
275 | } | |
bd166ef1 | 276 | EXPORT_SYMBOL_GPL(elv_rqhash_del); |
9817064b | 277 | |
70b3ea05 | 278 | void elv_rqhash_add(struct request_queue *q, struct request *rq) |
9817064b | 279 | { |
b374d18a | 280 | struct elevator_queue *e = q->elevator; |
9817064b JA |
281 | |
282 | BUG_ON(ELV_ON_HASH(rq)); | |
242d98f0 | 283 | hash_add(e->hash, &rq->hash, rq_hash_key(rq)); |
e8064021 | 284 | rq->rq_flags |= RQF_HASHED; |
9817064b | 285 | } |
bd166ef1 | 286 | EXPORT_SYMBOL_GPL(elv_rqhash_add); |
9817064b | 287 | |
70b3ea05 | 288 | void elv_rqhash_reposition(struct request_queue *q, struct request *rq) |
9817064b JA |
289 | { |
290 | __elv_rqhash_del(rq); | |
291 | elv_rqhash_add(q, rq); | |
292 | } | |
293 | ||
70b3ea05 | 294 | struct request *elv_rqhash_find(struct request_queue *q, sector_t offset) |
9817064b | 295 | { |
b374d18a | 296 | struct elevator_queue *e = q->elevator; |
b67bfe0d | 297 | struct hlist_node *next; |
9817064b JA |
298 | struct request *rq; |
299 | ||
ee89f812 | 300 | hash_for_each_possible_safe(e->hash, rq, next, hash, offset) { |
9817064b JA |
301 | BUG_ON(!ELV_ON_HASH(rq)); |
302 | ||
303 | if (unlikely(!rq_mergeable(rq))) { | |
304 | __elv_rqhash_del(rq); | |
305 | continue; | |
306 | } | |
307 | ||
308 | if (rq_hash_key(rq) == offset) | |
309 | return rq; | |
310 | } | |
311 | ||
312 | return NULL; | |
313 | } | |
314 | ||
2e662b65 JA |
315 | /* |
316 | * RB-tree support functions for inserting/lookup/removal of requests | |
317 | * in a sorted RB tree. | |
318 | */ | |
796d5116 | 319 | void elv_rb_add(struct rb_root *root, struct request *rq) |
2e662b65 JA |
320 | { |
321 | struct rb_node **p = &root->rb_node; | |
322 | struct rb_node *parent = NULL; | |
323 | struct request *__rq; | |
324 | ||
325 | while (*p) { | |
326 | parent = *p; | |
327 | __rq = rb_entry(parent, struct request, rb_node); | |
328 | ||
83096ebf | 329 | if (blk_rq_pos(rq) < blk_rq_pos(__rq)) |
2e662b65 | 330 | p = &(*p)->rb_left; |
796d5116 | 331 | else if (blk_rq_pos(rq) >= blk_rq_pos(__rq)) |
2e662b65 | 332 | p = &(*p)->rb_right; |
2e662b65 JA |
333 | } |
334 | ||
335 | rb_link_node(&rq->rb_node, parent, p); | |
336 | rb_insert_color(&rq->rb_node, root); | |
2e662b65 | 337 | } |
2e662b65 JA |
338 | EXPORT_SYMBOL(elv_rb_add); |
339 | ||
340 | void elv_rb_del(struct rb_root *root, struct request *rq) | |
341 | { | |
342 | BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); | |
343 | rb_erase(&rq->rb_node, root); | |
344 | RB_CLEAR_NODE(&rq->rb_node); | |
345 | } | |
2e662b65 JA |
346 | EXPORT_SYMBOL(elv_rb_del); |
347 | ||
348 | struct request *elv_rb_find(struct rb_root *root, sector_t sector) | |
349 | { | |
350 | struct rb_node *n = root->rb_node; | |
351 | struct request *rq; | |
352 | ||
353 | while (n) { | |
354 | rq = rb_entry(n, struct request, rb_node); | |
355 | ||
83096ebf | 356 | if (sector < blk_rq_pos(rq)) |
2e662b65 | 357 | n = n->rb_left; |
83096ebf | 358 | else if (sector > blk_rq_pos(rq)) |
2e662b65 JA |
359 | n = n->rb_right; |
360 | else | |
361 | return rq; | |
362 | } | |
363 | ||
364 | return NULL; | |
365 | } | |
2e662b65 JA |
366 | EXPORT_SYMBOL(elv_rb_find); |
367 | ||
8922e16c TH |
368 | /* |
369 | * Insert rq into dispatch queue of q. Queue lock must be held on | |
dbe7f76d | 370 | * entry. rq is sort instead into the dispatch queue. To be used by |
2e662b65 | 371 | * specific elevators. |
8922e16c | 372 | */ |
165125e1 | 373 | void elv_dispatch_sort(struct request_queue *q, struct request *rq) |
8922e16c TH |
374 | { |
375 | sector_t boundary; | |
8922e16c TH |
376 | struct list_head *entry; |
377 | ||
06b86245 TH |
378 | if (q->last_merge == rq) |
379 | q->last_merge = NULL; | |
9817064b JA |
380 | |
381 | elv_rqhash_del(q, rq); | |
382 | ||
15853af9 | 383 | q->nr_sorted--; |
06b86245 | 384 | |
1b47f531 | 385 | boundary = q->end_sector; |
8922e16c TH |
386 | list_for_each_prev(entry, &q->queue_head) { |
387 | struct request *pos = list_entry_rq(entry); | |
388 | ||
7afafc8a | 389 | if (req_op(rq) != req_op(pos)) |
e17fc0a1 | 390 | break; |
783660b2 JA |
391 | if (rq_data_dir(rq) != rq_data_dir(pos)) |
392 | break; | |
e8064021 | 393 | if (pos->rq_flags & (RQF_STARTED | RQF_SOFTBARRIER)) |
8922e16c | 394 | break; |
83096ebf TH |
395 | if (blk_rq_pos(rq) >= boundary) { |
396 | if (blk_rq_pos(pos) < boundary) | |
8922e16c TH |
397 | continue; |
398 | } else { | |
83096ebf | 399 | if (blk_rq_pos(pos) >= boundary) |
8922e16c TH |
400 | break; |
401 | } | |
83096ebf | 402 | if (blk_rq_pos(rq) >= blk_rq_pos(pos)) |
8922e16c TH |
403 | break; |
404 | } | |
405 | ||
406 | list_add(&rq->queuelist, entry); | |
407 | } | |
2e662b65 JA |
408 | EXPORT_SYMBOL(elv_dispatch_sort); |
409 | ||
9817064b | 410 | /* |
2e662b65 JA |
411 | * Insert rq into dispatch queue of q. Queue lock must be held on |
412 | * entry. rq is added to the back of the dispatch queue. To be used by | |
413 | * specific elevators. | |
9817064b JA |
414 | */ |
415 | void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) | |
416 | { | |
417 | if (q->last_merge == rq) | |
418 | q->last_merge = NULL; | |
419 | ||
420 | elv_rqhash_del(q, rq); | |
421 | ||
422 | q->nr_sorted--; | |
423 | ||
424 | q->end_sector = rq_end_sector(rq); | |
425 | q->boundary_rq = rq; | |
426 | list_add_tail(&rq->queuelist, &q->queue_head); | |
427 | } | |
2e662b65 JA |
428 | EXPORT_SYMBOL(elv_dispatch_add_tail); |
429 | ||
165125e1 | 430 | int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) |
1da177e4 | 431 | { |
b374d18a | 432 | struct elevator_queue *e = q->elevator; |
9817064b | 433 | struct request *__rq; |
06b86245 TH |
434 | int ret; |
435 | ||
488991e2 AB |
436 | /* |
437 | * Levels of merges: | |
438 | * nomerges: No merges at all attempted | |
439 | * noxmerges: Only simple one-hit cache try | |
440 | * merges: All merge tries attempted | |
441 | */ | |
7460d389 | 442 | if (blk_queue_nomerges(q) || !bio_mergeable(bio)) |
488991e2 AB |
443 | return ELEVATOR_NO_MERGE; |
444 | ||
9817064b JA |
445 | /* |
446 | * First try one-hit cache. | |
447 | */ | |
72ef799b | 448 | if (q->last_merge && elv_bio_merge_ok(q->last_merge, bio)) { |
050c8ea8 | 449 | ret = blk_try_merge(q->last_merge, bio); |
06b86245 TH |
450 | if (ret != ELEVATOR_NO_MERGE) { |
451 | *req = q->last_merge; | |
452 | return ret; | |
453 | } | |
454 | } | |
1da177e4 | 455 | |
488991e2 | 456 | if (blk_queue_noxmerges(q)) |
ac9fafa1 AB |
457 | return ELEVATOR_NO_MERGE; |
458 | ||
9817064b JA |
459 | /* |
460 | * See if our hash lookup can find a potential backmerge. | |
461 | */ | |
4f024f37 | 462 | __rq = elv_rqhash_find(q, bio->bi_iter.bi_sector); |
72ef799b | 463 | if (__rq && elv_bio_merge_ok(__rq, bio)) { |
9817064b JA |
464 | *req = __rq; |
465 | return ELEVATOR_BACK_MERGE; | |
466 | } | |
467 | ||
bd166ef1 JA |
468 | if (e->uses_mq && e->type->ops.mq.request_merge) |
469 | return e->type->ops.mq.request_merge(q, req, bio); | |
470 | else if (!e->uses_mq && e->type->ops.sq.elevator_merge_fn) | |
c51ca6cf | 471 | return e->type->ops.sq.elevator_merge_fn(q, req, bio); |
1da177e4 LT |
472 | |
473 | return ELEVATOR_NO_MERGE; | |
474 | } | |
475 | ||
5e84ea3a JA |
476 | /* |
477 | * Attempt to do an insertion back merge. Only check for the case where | |
478 | * we can append 'rq' to an existing request, so we can throw 'rq' away | |
479 | * afterwards. | |
480 | * | |
481 | * Returns true if we merged, false otherwise | |
482 | */ | |
bd166ef1 | 483 | bool elv_attempt_insert_merge(struct request_queue *q, struct request *rq) |
5e84ea3a JA |
484 | { |
485 | struct request *__rq; | |
bee0393c | 486 | bool ret; |
5e84ea3a JA |
487 | |
488 | if (blk_queue_nomerges(q)) | |
489 | return false; | |
490 | ||
491 | /* | |
492 | * First try one-hit cache. | |
493 | */ | |
494 | if (q->last_merge && blk_attempt_req_merge(q, q->last_merge, rq)) | |
495 | return true; | |
496 | ||
497 | if (blk_queue_noxmerges(q)) | |
498 | return false; | |
499 | ||
bee0393c | 500 | ret = false; |
5e84ea3a JA |
501 | /* |
502 | * See if our hash lookup can find a potential backmerge. | |
503 | */ | |
bee0393c SL |
504 | while (1) { |
505 | __rq = elv_rqhash_find(q, blk_rq_pos(rq)); | |
506 | if (!__rq || !blk_attempt_req_merge(q, __rq, rq)) | |
507 | break; | |
508 | ||
509 | /* The merged request could be merged with others, try again */ | |
510 | ret = true; | |
511 | rq = __rq; | |
512 | } | |
27419322 | 513 | |
bee0393c | 514 | return ret; |
5e84ea3a JA |
515 | } |
516 | ||
165125e1 | 517 | void elv_merged_request(struct request_queue *q, struct request *rq, int type) |
1da177e4 | 518 | { |
b374d18a | 519 | struct elevator_queue *e = q->elevator; |
1da177e4 | 520 | |
bd166ef1 JA |
521 | if (e->uses_mq && e->type->ops.mq.request_merged) |
522 | e->type->ops.mq.request_merged(q, rq, type); | |
523 | else if (!e->uses_mq && e->type->ops.sq.elevator_merged_fn) | |
c51ca6cf | 524 | e->type->ops.sq.elevator_merged_fn(q, rq, type); |
06b86245 | 525 | |
2e662b65 JA |
526 | if (type == ELEVATOR_BACK_MERGE) |
527 | elv_rqhash_reposition(q, rq); | |
9817064b | 528 | |
06b86245 | 529 | q->last_merge = rq; |
1da177e4 LT |
530 | } |
531 | ||
165125e1 | 532 | void elv_merge_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
533 | struct request *next) |
534 | { | |
b374d18a | 535 | struct elevator_queue *e = q->elevator; |
bd166ef1 JA |
536 | bool next_sorted = false; |
537 | ||
538 | if (e->uses_mq && e->type->ops.mq.requests_merged) | |
539 | e->type->ops.mq.requests_merged(q, rq, next); | |
540 | else if (e->type->ops.sq.elevator_merge_req_fn) { | |
541 | next_sorted = next->rq_flags & RQF_SORTED; | |
542 | if (next_sorted) | |
543 | e->type->ops.sq.elevator_merge_req_fn(q, rq, next); | |
544 | } | |
06b86245 | 545 | |
9817064b | 546 | elv_rqhash_reposition(q, rq); |
9817064b | 547 | |
5e84ea3a JA |
548 | if (next_sorted) { |
549 | elv_rqhash_del(q, next); | |
550 | q->nr_sorted--; | |
551 | } | |
552 | ||
06b86245 | 553 | q->last_merge = rq; |
1da177e4 LT |
554 | } |
555 | ||
812d4026 DS |
556 | void elv_bio_merged(struct request_queue *q, struct request *rq, |
557 | struct bio *bio) | |
558 | { | |
559 | struct elevator_queue *e = q->elevator; | |
560 | ||
bd166ef1 JA |
561 | if (WARN_ON_ONCE(e->uses_mq)) |
562 | return; | |
563 | ||
c51ca6cf JA |
564 | if (e->type->ops.sq.elevator_bio_merged_fn) |
565 | e->type->ops.sq.elevator_bio_merged_fn(q, rq, bio); | |
812d4026 DS |
566 | } |
567 | ||
47fafbc7 | 568 | #ifdef CONFIG_PM |
c8158819 LM |
569 | static void blk_pm_requeue_request(struct request *rq) |
570 | { | |
e8064021 | 571 | if (rq->q->dev && !(rq->rq_flags & RQF_PM)) |
c8158819 LM |
572 | rq->q->nr_pending--; |
573 | } | |
574 | ||
575 | static void blk_pm_add_request(struct request_queue *q, struct request *rq) | |
576 | { | |
e8064021 | 577 | if (q->dev && !(rq->rq_flags & RQF_PM) && q->nr_pending++ == 0 && |
c8158819 LM |
578 | (q->rpm_status == RPM_SUSPENDED || q->rpm_status == RPM_SUSPENDING)) |
579 | pm_request_resume(q->dev); | |
580 | } | |
581 | #else | |
582 | static inline void blk_pm_requeue_request(struct request *rq) {} | |
583 | static inline void blk_pm_add_request(struct request_queue *q, | |
584 | struct request *rq) | |
585 | { | |
586 | } | |
587 | #endif | |
588 | ||
165125e1 | 589 | void elv_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 590 | { |
1da177e4 LT |
591 | /* |
592 | * it already went through dequeue, we need to decrement the | |
593 | * in_flight count again | |
594 | */ | |
8922e16c | 595 | if (blk_account_rq(rq)) { |
0a7ae2ff | 596 | q->in_flight[rq_is_sync(rq)]--; |
e8064021 | 597 | if (rq->rq_flags & RQF_SORTED) |
cad97516 | 598 | elv_deactivate_rq(q, rq); |
8922e16c | 599 | } |
1da177e4 | 600 | |
e8064021 | 601 | rq->rq_flags &= ~RQF_STARTED; |
1da177e4 | 602 | |
c8158819 LM |
603 | blk_pm_requeue_request(rq); |
604 | ||
b710a480 | 605 | __elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE); |
1da177e4 LT |
606 | } |
607 | ||
26308eab | 608 | void elv_drain_elevator(struct request_queue *q) |
15853af9 | 609 | { |
bd166ef1 | 610 | struct elevator_queue *e = q->elevator; |
15853af9 | 611 | static int printed; |
e3c78ca5 | 612 | |
bd166ef1 JA |
613 | if (WARN_ON_ONCE(e->uses_mq)) |
614 | return; | |
615 | ||
e3c78ca5 TH |
616 | lockdep_assert_held(q->queue_lock); |
617 | ||
bd166ef1 | 618 | while (e->type->ops.sq.elevator_dispatch_fn(q, 1)) |
15853af9 | 619 | ; |
e3c78ca5 | 620 | if (q->nr_sorted && printed++ < 10) { |
15853af9 TH |
621 | printk(KERN_ERR "%s: forced dispatching is broken " |
622 | "(nr_sorted=%u), please report this\n", | |
22f746e2 | 623 | q->elevator->type->elevator_name, q->nr_sorted); |
15853af9 TH |
624 | } |
625 | } | |
626 | ||
b710a480 | 627 | void __elv_add_request(struct request_queue *q, struct request *rq, int where) |
1da177e4 | 628 | { |
5f3ea37c | 629 | trace_block_rq_insert(q, rq); |
2056a782 | 630 | |
c8158819 LM |
631 | blk_pm_add_request(q, rq); |
632 | ||
1da177e4 LT |
633 | rq->q = q; |
634 | ||
e8064021 | 635 | if (rq->rq_flags & RQF_SOFTBARRIER) { |
b710a480 | 636 | /* barriers are scheduling boundary, update end_sector */ |
57292b58 | 637 | if (!blk_rq_is_passthrough(rq)) { |
b710a480 JA |
638 | q->end_sector = rq_end_sector(rq); |
639 | q->boundary_rq = rq; | |
640 | } | |
e8064021 | 641 | } else if (!(rq->rq_flags & RQF_ELVPRIV) && |
3aa72873 JA |
642 | (where == ELEVATOR_INSERT_SORT || |
643 | where == ELEVATOR_INSERT_SORT_MERGE)) | |
b710a480 JA |
644 | where = ELEVATOR_INSERT_BACK; |
645 | ||
8922e16c | 646 | switch (where) { |
28e7d184 | 647 | case ELEVATOR_INSERT_REQUEUE: |
8922e16c | 648 | case ELEVATOR_INSERT_FRONT: |
e8064021 | 649 | rq->rq_flags |= RQF_SOFTBARRIER; |
8922e16c TH |
650 | list_add(&rq->queuelist, &q->queue_head); |
651 | break; | |
652 | ||
653 | case ELEVATOR_INSERT_BACK: | |
e8064021 | 654 | rq->rq_flags |= RQF_SOFTBARRIER; |
15853af9 | 655 | elv_drain_elevator(q); |
8922e16c TH |
656 | list_add_tail(&rq->queuelist, &q->queue_head); |
657 | /* | |
658 | * We kick the queue here for the following reasons. | |
659 | * - The elevator might have returned NULL previously | |
660 | * to delay requests and returned them now. As the | |
661 | * queue wasn't empty before this request, ll_rw_blk | |
662 | * won't run the queue on return, resulting in hang. | |
663 | * - Usually, back inserted requests won't be merged | |
664 | * with anything. There's no point in delaying queue | |
665 | * processing. | |
666 | */ | |
24ecfbe2 | 667 | __blk_run_queue(q); |
8922e16c TH |
668 | break; |
669 | ||
5e84ea3a JA |
670 | case ELEVATOR_INSERT_SORT_MERGE: |
671 | /* | |
672 | * If we succeed in merging this request with one in the | |
673 | * queue already, we are done - rq has now been freed, | |
674 | * so no need to do anything further. | |
675 | */ | |
676 | if (elv_attempt_insert_merge(q, rq)) | |
677 | break; | |
8922e16c | 678 | case ELEVATOR_INSERT_SORT: |
57292b58 | 679 | BUG_ON(blk_rq_is_passthrough(rq)); |
e8064021 | 680 | rq->rq_flags |= RQF_SORTED; |
15853af9 | 681 | q->nr_sorted++; |
9817064b JA |
682 | if (rq_mergeable(rq)) { |
683 | elv_rqhash_add(q, rq); | |
684 | if (!q->last_merge) | |
685 | q->last_merge = rq; | |
686 | } | |
687 | ||
ca23509f TH |
688 | /* |
689 | * Some ioscheds (cfq) run q->request_fn directly, so | |
690 | * rq cannot be accessed after calling | |
691 | * elevator_add_req_fn. | |
692 | */ | |
c51ca6cf | 693 | q->elevator->type->ops.sq.elevator_add_req_fn(q, rq); |
8922e16c TH |
694 | break; |
695 | ||
ae1b1539 | 696 | case ELEVATOR_INSERT_FLUSH: |
e8064021 | 697 | rq->rq_flags |= RQF_SOFTBARRIER; |
ae1b1539 TH |
698 | blk_insert_flush(rq); |
699 | break; | |
8922e16c TH |
700 | default: |
701 | printk(KERN_ERR "%s: bad insertion point %d\n", | |
24c03d47 | 702 | __func__, where); |
8922e16c TH |
703 | BUG(); |
704 | } | |
1da177e4 | 705 | } |
2e662b65 JA |
706 | EXPORT_SYMBOL(__elv_add_request); |
707 | ||
7eaceacc | 708 | void elv_add_request(struct request_queue *q, struct request *rq, int where) |
1da177e4 LT |
709 | { |
710 | unsigned long flags; | |
711 | ||
712 | spin_lock_irqsave(q->queue_lock, flags); | |
7eaceacc | 713 | __elv_add_request(q, rq, where); |
1da177e4 LT |
714 | spin_unlock_irqrestore(q->queue_lock, flags); |
715 | } | |
2e662b65 JA |
716 | EXPORT_SYMBOL(elv_add_request); |
717 | ||
165125e1 | 718 | struct request *elv_latter_request(struct request_queue *q, struct request *rq) |
1da177e4 | 719 | { |
b374d18a | 720 | struct elevator_queue *e = q->elevator; |
1da177e4 | 721 | |
bd166ef1 JA |
722 | if (e->uses_mq && e->type->ops.mq.next_request) |
723 | return e->type->ops.mq.next_request(q, rq); | |
724 | else if (!e->uses_mq && e->type->ops.sq.elevator_latter_req_fn) | |
c51ca6cf | 725 | return e->type->ops.sq.elevator_latter_req_fn(q, rq); |
bd166ef1 | 726 | |
1da177e4 LT |
727 | return NULL; |
728 | } | |
729 | ||
165125e1 | 730 | struct request *elv_former_request(struct request_queue *q, struct request *rq) |
1da177e4 | 731 | { |
b374d18a | 732 | struct elevator_queue *e = q->elevator; |
1da177e4 | 733 | |
bd166ef1 JA |
734 | if (e->uses_mq && e->type->ops.mq.former_request) |
735 | return e->type->ops.mq.former_request(q, rq); | |
736 | if (!e->uses_mq && e->type->ops.sq.elevator_former_req_fn) | |
c51ca6cf | 737 | return e->type->ops.sq.elevator_former_req_fn(q, rq); |
1da177e4 LT |
738 | return NULL; |
739 | } | |
740 | ||
852c788f TH |
741 | int elv_set_request(struct request_queue *q, struct request *rq, |
742 | struct bio *bio, gfp_t gfp_mask) | |
1da177e4 | 743 | { |
b374d18a | 744 | struct elevator_queue *e = q->elevator; |
1da177e4 | 745 | |
bd166ef1 JA |
746 | if (WARN_ON_ONCE(e->uses_mq)) |
747 | return 0; | |
748 | ||
c51ca6cf JA |
749 | if (e->type->ops.sq.elevator_set_req_fn) |
750 | return e->type->ops.sq.elevator_set_req_fn(q, rq, bio, gfp_mask); | |
1da177e4 LT |
751 | return 0; |
752 | } | |
753 | ||
165125e1 | 754 | void elv_put_request(struct request_queue *q, struct request *rq) |
1da177e4 | 755 | { |
b374d18a | 756 | struct elevator_queue *e = q->elevator; |
1da177e4 | 757 | |
bd166ef1 JA |
758 | if (WARN_ON_ONCE(e->uses_mq)) |
759 | return; | |
760 | ||
c51ca6cf JA |
761 | if (e->type->ops.sq.elevator_put_req_fn) |
762 | e->type->ops.sq.elevator_put_req_fn(rq); | |
1da177e4 LT |
763 | } |
764 | ||
ef295ecf | 765 | int elv_may_queue(struct request_queue *q, unsigned int op) |
1da177e4 | 766 | { |
b374d18a | 767 | struct elevator_queue *e = q->elevator; |
1da177e4 | 768 | |
bd166ef1 JA |
769 | if (WARN_ON_ONCE(e->uses_mq)) |
770 | return 0; | |
771 | ||
c51ca6cf JA |
772 | if (e->type->ops.sq.elevator_may_queue_fn) |
773 | return e->type->ops.sq.elevator_may_queue_fn(q, op); | |
1da177e4 LT |
774 | |
775 | return ELV_MQUEUE_MAY; | |
776 | } | |
777 | ||
165125e1 | 778 | void elv_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 779 | { |
b374d18a | 780 | struct elevator_queue *e = q->elevator; |
1da177e4 | 781 | |
bd166ef1 JA |
782 | if (WARN_ON_ONCE(e->uses_mq)) |
783 | return; | |
784 | ||
1da177e4 LT |
785 | /* |
786 | * request is released from the driver, io must be done | |
787 | */ | |
8922e16c | 788 | if (blk_account_rq(rq)) { |
0a7ae2ff | 789 | q->in_flight[rq_is_sync(rq)]--; |
e8064021 | 790 | if ((rq->rq_flags & RQF_SORTED) && |
c51ca6cf JA |
791 | e->type->ops.sq.elevator_completed_req_fn) |
792 | e->type->ops.sq.elevator_completed_req_fn(q, rq); | |
1bc691d3 | 793 | } |
1da177e4 LT |
794 | } |
795 | ||
3d1ab40f AV |
796 | #define to_elv(atr) container_of((atr), struct elv_fs_entry, attr) |
797 | ||
798 | static ssize_t | |
799 | elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
1da177e4 | 800 | { |
3d1ab40f | 801 | struct elv_fs_entry *entry = to_elv(attr); |
b374d18a | 802 | struct elevator_queue *e; |
3d1ab40f AV |
803 | ssize_t error; |
804 | ||
805 | if (!entry->show) | |
806 | return -EIO; | |
807 | ||
b374d18a | 808 | e = container_of(kobj, struct elevator_queue, kobj); |
3d1ab40f | 809 | mutex_lock(&e->sysfs_lock); |
22f746e2 | 810 | error = e->type ? entry->show(e, page) : -ENOENT; |
3d1ab40f AV |
811 | mutex_unlock(&e->sysfs_lock); |
812 | return error; | |
813 | } | |
1da177e4 | 814 | |
3d1ab40f AV |
815 | static ssize_t |
816 | elv_attr_store(struct kobject *kobj, struct attribute *attr, | |
817 | const char *page, size_t length) | |
818 | { | |
3d1ab40f | 819 | struct elv_fs_entry *entry = to_elv(attr); |
b374d18a | 820 | struct elevator_queue *e; |
3d1ab40f | 821 | ssize_t error; |
1da177e4 | 822 | |
3d1ab40f AV |
823 | if (!entry->store) |
824 | return -EIO; | |
1da177e4 | 825 | |
b374d18a | 826 | e = container_of(kobj, struct elevator_queue, kobj); |
3d1ab40f | 827 | mutex_lock(&e->sysfs_lock); |
22f746e2 | 828 | error = e->type ? entry->store(e, page, length) : -ENOENT; |
3d1ab40f AV |
829 | mutex_unlock(&e->sysfs_lock); |
830 | return error; | |
831 | } | |
832 | ||
52cf25d0 | 833 | static const struct sysfs_ops elv_sysfs_ops = { |
3d1ab40f AV |
834 | .show = elv_attr_show, |
835 | .store = elv_attr_store, | |
836 | }; | |
837 | ||
838 | static struct kobj_type elv_ktype = { | |
839 | .sysfs_ops = &elv_sysfs_ops, | |
840 | .release = elevator_release, | |
841 | }; | |
842 | ||
5a5bafdc | 843 | int elv_register_queue(struct request_queue *q) |
3d1ab40f | 844 | { |
5a5bafdc | 845 | struct elevator_queue *e = q->elevator; |
3d1ab40f AV |
846 | int error; |
847 | ||
b2d6db58 | 848 | error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); |
3d1ab40f | 849 | if (!error) { |
22f746e2 | 850 | struct elv_fs_entry *attr = e->type->elevator_attrs; |
3d1ab40f | 851 | if (attr) { |
e572ec7e AV |
852 | while (attr->attr.name) { |
853 | if (sysfs_create_file(&e->kobj, &attr->attr)) | |
3d1ab40f | 854 | break; |
e572ec7e | 855 | attr++; |
3d1ab40f AV |
856 | } |
857 | } | |
858 | kobject_uevent(&e->kobj, KOBJ_ADD); | |
430c62fb | 859 | e->registered = 1; |
bd166ef1 | 860 | if (!e->uses_mq && e->type->ops.sq.elevator_registered_fn) |
c51ca6cf | 861 | e->type->ops.sq.elevator_registered_fn(q); |
3d1ab40f AV |
862 | } |
863 | return error; | |
1da177e4 | 864 | } |
f8fc877d | 865 | EXPORT_SYMBOL(elv_register_queue); |
bc1c1169 | 866 | |
1da177e4 LT |
867 | void elv_unregister_queue(struct request_queue *q) |
868 | { | |
f8fc877d TH |
869 | if (q) { |
870 | struct elevator_queue *e = q->elevator; | |
871 | ||
872 | kobject_uevent(&e->kobj, KOBJ_REMOVE); | |
873 | kobject_del(&e->kobj); | |
874 | e->registered = 0; | |
875 | } | |
1da177e4 | 876 | } |
01effb0d | 877 | EXPORT_SYMBOL(elv_unregister_queue); |
1da177e4 | 878 | |
e567bf71 | 879 | int elv_register(struct elevator_type *e) |
1da177e4 | 880 | { |
1ffb96c5 | 881 | char *def = ""; |
2a12dcd7 | 882 | |
3d3c2379 TH |
883 | /* create icq_cache if requested */ |
884 | if (e->icq_size) { | |
885 | if (WARN_ON(e->icq_size < sizeof(struct io_cq)) || | |
886 | WARN_ON(e->icq_align < __alignof__(struct io_cq))) | |
887 | return -EINVAL; | |
888 | ||
889 | snprintf(e->icq_cache_name, sizeof(e->icq_cache_name), | |
890 | "%s_io_cq", e->elevator_name); | |
891 | e->icq_cache = kmem_cache_create(e->icq_cache_name, e->icq_size, | |
892 | e->icq_align, 0, NULL); | |
893 | if (!e->icq_cache) | |
894 | return -ENOMEM; | |
895 | } | |
896 | ||
897 | /* register, don't allow duplicate names */ | |
2a12dcd7 | 898 | spin_lock(&elv_list_lock); |
3d3c2379 TH |
899 | if (elevator_find(e->elevator_name)) { |
900 | spin_unlock(&elv_list_lock); | |
901 | if (e->icq_cache) | |
902 | kmem_cache_destroy(e->icq_cache); | |
903 | return -EBUSY; | |
904 | } | |
1da177e4 | 905 | list_add_tail(&e->list, &elv_list); |
2a12dcd7 | 906 | spin_unlock(&elv_list_lock); |
1da177e4 | 907 | |
3d3c2379 | 908 | /* print pretty message */ |
5f003976 ND |
909 | if (!strcmp(e->elevator_name, chosen_elevator) || |
910 | (!*chosen_elevator && | |
911 | !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) | |
1ffb96c5 TV |
912 | def = " (default)"; |
913 | ||
4eb166d9 JA |
914 | printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, |
915 | def); | |
3d3c2379 | 916 | return 0; |
1da177e4 LT |
917 | } |
918 | EXPORT_SYMBOL_GPL(elv_register); | |
919 | ||
920 | void elv_unregister(struct elevator_type *e) | |
921 | { | |
3d3c2379 | 922 | /* unregister */ |
2a12dcd7 | 923 | spin_lock(&elv_list_lock); |
1da177e4 | 924 | list_del_init(&e->list); |
2a12dcd7 | 925 | spin_unlock(&elv_list_lock); |
3d3c2379 TH |
926 | |
927 | /* | |
928 | * Destroy icq_cache if it exists. icq's are RCU managed. Make | |
929 | * sure all RCU operations are complete before proceeding. | |
930 | */ | |
931 | if (e->icq_cache) { | |
932 | rcu_barrier(); | |
933 | kmem_cache_destroy(e->icq_cache); | |
934 | e->icq_cache = NULL; | |
935 | } | |
1da177e4 LT |
936 | } |
937 | EXPORT_SYMBOL_GPL(elv_unregister); | |
938 | ||
939 | /* | |
940 | * switch to new_e io scheduler. be careful not to introduce deadlocks - | |
941 | * we don't free the old io scheduler, before we have allocated what we | |
942 | * need for the new one. this way we have a chance of going back to the old | |
cb98fc8b | 943 | * one, if the new one fails init for some reason. |
1da177e4 | 944 | */ |
165125e1 | 945 | static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) |
1da177e4 | 946 | { |
5a5bafdc | 947 | struct elevator_queue *old = q->elevator; |
bd166ef1 | 948 | bool old_registered = false; |
e8989fae | 949 | int err; |
1da177e4 | 950 | |
bd166ef1 JA |
951 | if (q->mq_ops) { |
952 | blk_mq_freeze_queue(q); | |
953 | blk_mq_quiesce_queue(q); | |
954 | } | |
955 | ||
5a5bafdc TH |
956 | /* |
957 | * Turn on BYPASS and drain all requests w/ elevator private data. | |
958 | * Block layer doesn't call into a quiesced elevator - all requests | |
959 | * are directly put on the dispatch list without elevator data | |
960 | * using INSERT_BACK. All requests have SOFTBARRIER set and no | |
961 | * merge happens either. | |
962 | */ | |
bd166ef1 JA |
963 | if (old) { |
964 | old_registered = old->registered; | |
965 | ||
966 | if (old->uses_mq) | |
967 | blk_mq_sched_teardown(q); | |
cb98fc8b | 968 | |
bd166ef1 JA |
969 | if (!q->mq_ops) |
970 | blk_queue_bypass_start(q); | |
1da177e4 | 971 | |
bd166ef1 JA |
972 | /* unregister and clear all auxiliary data of the old elevator */ |
973 | if (old_registered) | |
974 | elv_unregister_queue(q); | |
975 | ||
976 | spin_lock_irq(q->queue_lock); | |
977 | ioc_clear_queue(q); | |
978 | spin_unlock_irq(q->queue_lock); | |
979 | } | |
f8fc877d | 980 | |
5a5bafdc | 981 | /* allocate, init and register new elevator */ |
bd166ef1 JA |
982 | if (new_e) { |
983 | if (new_e->uses_mq) { | |
984 | err = blk_mq_sched_setup(q); | |
985 | if (!err) | |
986 | err = new_e->ops.mq.init_sched(q, new_e); | |
987 | } else | |
988 | err = new_e->ops.sq.elevator_init_fn(q, new_e); | |
989 | if (err) | |
990 | goto fail_init; | |
5a5bafdc | 991 | |
5a5bafdc TH |
992 | err = elv_register_queue(q); |
993 | if (err) | |
994 | goto fail_register; | |
bd166ef1 JA |
995 | } else |
996 | q->elevator = NULL; | |
5a5bafdc TH |
997 | |
998 | /* done, kill the old one and finish */ | |
bd166ef1 JA |
999 | if (old) { |
1000 | elevator_exit(old); | |
1001 | if (!q->mq_ops) | |
1002 | blk_queue_bypass_end(q); | |
1003 | } | |
1004 | ||
1005 | if (q->mq_ops) { | |
1006 | blk_mq_unfreeze_queue(q); | |
1007 | blk_mq_start_stopped_hw_queues(q, true); | |
1008 | } | |
75ad23bc | 1009 | |
bd166ef1 JA |
1010 | if (new_e) |
1011 | blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name); | |
1012 | else | |
1013 | blk_add_trace_msg(q, "elv switch: none"); | |
4722dc52 | 1014 | |
5dd531a0 | 1015 | return 0; |
1da177e4 LT |
1016 | |
1017 | fail_register: | |
bd166ef1 JA |
1018 | if (q->mq_ops) |
1019 | blk_mq_sched_teardown(q); | |
5a5bafdc TH |
1020 | elevator_exit(q->elevator); |
1021 | fail_init: | |
1022 | /* switch failed, restore and re-register old elevator */ | |
bd166ef1 JA |
1023 | if (old) { |
1024 | q->elevator = old; | |
1025 | elv_register_queue(q); | |
1026 | if (!q->mq_ops) | |
1027 | blk_queue_bypass_end(q); | |
1028 | } | |
1029 | if (q->mq_ops) { | |
1030 | blk_mq_unfreeze_queue(q); | |
1031 | blk_mq_start_stopped_hw_queues(q, true); | |
1032 | } | |
75ad23bc | 1033 | |
5dd531a0 | 1034 | return err; |
1da177e4 LT |
1035 | } |
1036 | ||
5dd531a0 JA |
1037 | /* |
1038 | * Switch this queue to the given IO scheduler. | |
1039 | */ | |
7c8a3679 | 1040 | static int __elevator_change(struct request_queue *q, const char *name) |
1da177e4 LT |
1041 | { |
1042 | char elevator_name[ELV_NAME_MAX]; | |
1043 | struct elevator_type *e; | |
1044 | ||
bd166ef1 JA |
1045 | /* |
1046 | * Special case for mq, turn off scheduling | |
1047 | */ | |
1048 | if (q->mq_ops && !strncmp(name, "none", 4)) | |
1049 | return elevator_switch(q, NULL); | |
cd43e26f | 1050 | |
ee2e992c | 1051 | strlcpy(elevator_name, name, sizeof(elevator_name)); |
21c3c5d2 | 1052 | e = elevator_get(strstrip(elevator_name), true); |
1da177e4 LT |
1053 | if (!e) { |
1054 | printk(KERN_ERR "elevator: type %s not found\n", elevator_name); | |
1055 | return -EINVAL; | |
1056 | } | |
1057 | ||
bd166ef1 JA |
1058 | if (q->elevator && |
1059 | !strcmp(elevator_name, q->elevator->type->elevator_name)) { | |
2ca7d93b | 1060 | elevator_put(e); |
5dd531a0 | 1061 | return 0; |
2ca7d93b | 1062 | } |
1da177e4 | 1063 | |
bd166ef1 JA |
1064 | if (!e->uses_mq && q->mq_ops) { |
1065 | elevator_put(e); | |
1066 | return -EINVAL; | |
1067 | } | |
1068 | if (e->uses_mq && !q->mq_ops) { | |
1069 | elevator_put(e); | |
1070 | return -EINVAL; | |
1071 | } | |
1072 | ||
5dd531a0 JA |
1073 | return elevator_switch(q, e); |
1074 | } | |
7c8a3679 TS |
1075 | |
1076 | int elevator_change(struct request_queue *q, const char *name) | |
1077 | { | |
1078 | int ret; | |
1079 | ||
1080 | /* Protect q->elevator from elevator_init() */ | |
1081 | mutex_lock(&q->sysfs_lock); | |
1082 | ret = __elevator_change(q, name); | |
1083 | mutex_unlock(&q->sysfs_lock); | |
1084 | ||
1085 | return ret; | |
1086 | } | |
5dd531a0 JA |
1087 | EXPORT_SYMBOL(elevator_change); |
1088 | ||
1089 | ssize_t elv_iosched_store(struct request_queue *q, const char *name, | |
1090 | size_t count) | |
1091 | { | |
1092 | int ret; | |
1093 | ||
bd166ef1 | 1094 | if (!(q->mq_ops || q->request_fn)) |
5dd531a0 JA |
1095 | return count; |
1096 | ||
7c8a3679 | 1097 | ret = __elevator_change(q, name); |
5dd531a0 JA |
1098 | if (!ret) |
1099 | return count; | |
1100 | ||
1101 | printk(KERN_ERR "elevator: switch to %s failed\n", name); | |
1102 | return ret; | |
1da177e4 LT |
1103 | } |
1104 | ||
165125e1 | 1105 | ssize_t elv_iosched_show(struct request_queue *q, char *name) |
1da177e4 | 1106 | { |
b374d18a | 1107 | struct elevator_queue *e = q->elevator; |
bd166ef1 | 1108 | struct elevator_type *elv = NULL; |
70cee26e | 1109 | struct elevator_type *__e; |
1da177e4 LT |
1110 | int len = 0; |
1111 | ||
bd166ef1 | 1112 | if (!blk_queue_stackable(q)) |
cd43e26f MP |
1113 | return sprintf(name, "none\n"); |
1114 | ||
bd166ef1 JA |
1115 | if (!q->elevator) |
1116 | len += sprintf(name+len, "[none] "); | |
1117 | else | |
1118 | elv = e->type; | |
cd43e26f | 1119 | |
2a12dcd7 | 1120 | spin_lock(&elv_list_lock); |
70cee26e | 1121 | list_for_each_entry(__e, &elv_list, list) { |
bd166ef1 | 1122 | if (elv && !strcmp(elv->elevator_name, __e->elevator_name)) { |
1da177e4 | 1123 | len += sprintf(name+len, "[%s] ", elv->elevator_name); |
bd166ef1 JA |
1124 | continue; |
1125 | } | |
1126 | if (__e->uses_mq && q->mq_ops) | |
1127 | len += sprintf(name+len, "%s ", __e->elevator_name); | |
1128 | else if (!__e->uses_mq && !q->mq_ops) | |
1da177e4 LT |
1129 | len += sprintf(name+len, "%s ", __e->elevator_name); |
1130 | } | |
2a12dcd7 | 1131 | spin_unlock(&elv_list_lock); |
1da177e4 | 1132 | |
bd166ef1 JA |
1133 | if (q->mq_ops && q->elevator) |
1134 | len += sprintf(name+len, "none"); | |
1135 | ||
1da177e4 LT |
1136 | len += sprintf(len+name, "\n"); |
1137 | return len; | |
1138 | } | |
1139 | ||
165125e1 JA |
1140 | struct request *elv_rb_former_request(struct request_queue *q, |
1141 | struct request *rq) | |
2e662b65 JA |
1142 | { |
1143 | struct rb_node *rbprev = rb_prev(&rq->rb_node); | |
1144 | ||
1145 | if (rbprev) | |
1146 | return rb_entry_rq(rbprev); | |
1147 | ||
1148 | return NULL; | |
1149 | } | |
2e662b65 JA |
1150 | EXPORT_SYMBOL(elv_rb_former_request); |
1151 | ||
165125e1 JA |
1152 | struct request *elv_rb_latter_request(struct request_queue *q, |
1153 | struct request *rq) | |
2e662b65 JA |
1154 | { |
1155 | struct rb_node *rbnext = rb_next(&rq->rb_node); | |
1156 | ||
1157 | if (rbnext) | |
1158 | return rb_entry_rq(rbnext); | |
1159 | ||
1160 | return NULL; | |
1161 | } | |
2e662b65 | 1162 | EXPORT_SYMBOL(elv_rb_latter_request); |