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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef BLK_INTERNAL_H
3#define BLK_INTERNAL_H
4
5#include <linux/blk-crypto.h>
6#include <linux/memblock.h> /* for max_pfn/max_low_pfn */
7#include <xen/xen.h>
8#include "blk-crypto-internal.h"
9
10struct elevator_type;
11
12/* Max future timer expiry for timeouts */
13#define BLK_MAX_TIMEOUT (5 * HZ)
14
15extern struct dentry *blk_debugfs_root;
16
17struct blk_flush_queue {
18 spinlock_t mq_flush_lock;
19 unsigned int flush_pending_idx:1;
20 unsigned int flush_running_idx:1;
21 blk_status_t rq_status;
22 unsigned long flush_pending_since;
23 struct list_head flush_queue[2];
24 unsigned long flush_data_in_flight;
25 struct request *flush_rq;
26};
27
28bool is_flush_rq(struct request *req);
29
30struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
31 gfp_t flags);
32void blk_free_flush_queue(struct blk_flush_queue *q);
33
34void blk_freeze_queue(struct request_queue *q);
35void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic);
36void blk_queue_start_drain(struct request_queue *q);
37int __bio_queue_enter(struct request_queue *q, struct bio *bio);
38void submit_bio_noacct_nocheck(struct bio *bio);
39
40static inline bool blk_try_enter_queue(struct request_queue *q, bool pm)
41{
42 rcu_read_lock();
43 if (!percpu_ref_tryget_live_rcu(&q->q_usage_counter))
44 goto fail;
45
46 /*
47 * The code that increments the pm_only counter must ensure that the
48 * counter is globally visible before the queue is unfrozen.
49 */
50 if (blk_queue_pm_only(q) &&
51 (!pm || queue_rpm_status(q) == RPM_SUSPENDED))
52 goto fail_put;
53
54 rcu_read_unlock();
55 return true;
56
57fail_put:
58 blk_queue_exit(q);
59fail:
60 rcu_read_unlock();
61 return false;
62}
63
64static inline int bio_queue_enter(struct bio *bio)
65{
66 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
67
68 if (blk_try_enter_queue(q, false))
69 return 0;
70 return __bio_queue_enter(q, bio);
71}
72
73#define BIO_INLINE_VECS 4
74struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,
75 gfp_t gfp_mask);
76void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs);
77
78bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
79 struct page *page, unsigned len, unsigned offset,
80 bool *same_page);
81
82static inline bool biovec_phys_mergeable(struct request_queue *q,
83 struct bio_vec *vec1, struct bio_vec *vec2)
84{
85 unsigned long mask = queue_segment_boundary(q);
86 phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset;
87 phys_addr_t addr2 = page_to_phys(vec2->bv_page) + vec2->bv_offset;
88
89 /*
90 * Merging adjacent physical pages may not work correctly under KMSAN
91 * if their metadata pages aren't adjacent. Just disable merging.
92 */
93 if (IS_ENABLED(CONFIG_KMSAN))
94 return false;
95
96 if (addr1 + vec1->bv_len != addr2)
97 return false;
98 if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page))
99 return false;
100 if ((addr1 | mask) != ((addr2 + vec2->bv_len - 1) | mask))
101 return false;
102 return true;
103}
104
105static inline bool __bvec_gap_to_prev(const struct queue_limits *lim,
106 struct bio_vec *bprv, unsigned int offset)
107{
108 return (offset & lim->virt_boundary_mask) ||
109 ((bprv->bv_offset + bprv->bv_len) & lim->virt_boundary_mask);
110}
111
112/*
113 * Check if adding a bio_vec after bprv with offset would create a gap in
114 * the SG list. Most drivers don't care about this, but some do.
115 */
116static inline bool bvec_gap_to_prev(const struct queue_limits *lim,
117 struct bio_vec *bprv, unsigned int offset)
118{
119 if (!lim->virt_boundary_mask)
120 return false;
121 return __bvec_gap_to_prev(lim, bprv, offset);
122}
123
124static inline bool rq_mergeable(struct request *rq)
125{
126 if (blk_rq_is_passthrough(rq))
127 return false;
128
129 if (req_op(rq) == REQ_OP_FLUSH)
130 return false;
131
132 if (req_op(rq) == REQ_OP_WRITE_ZEROES)
133 return false;
134
135 if (req_op(rq) == REQ_OP_ZONE_APPEND)
136 return false;
137
138 if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
139 return false;
140 if (rq->rq_flags & RQF_NOMERGE_FLAGS)
141 return false;
142
143 return true;
144}
145
146/*
147 * There are two different ways to handle DISCARD merges:
148 * 1) If max_discard_segments > 1, the driver treats every bio as a range and
149 * send the bios to controller together. The ranges don't need to be
150 * contiguous.
151 * 2) Otherwise, the request will be normal read/write requests. The ranges
152 * need to be contiguous.
153 */
154static inline bool blk_discard_mergable(struct request *req)
155{
156 if (req_op(req) == REQ_OP_DISCARD &&
157 queue_max_discard_segments(req->q) > 1)
158 return true;
159 return false;
160}
161
162static inline unsigned int blk_rq_get_max_segments(struct request *rq)
163{
164 if (req_op(rq) == REQ_OP_DISCARD)
165 return queue_max_discard_segments(rq->q);
166 return queue_max_segments(rq->q);
167}
168
169static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
170 enum req_op op)
171{
172 if (unlikely(op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE))
173 return min(q->limits.max_discard_sectors,
174 UINT_MAX >> SECTOR_SHIFT);
175
176 if (unlikely(op == REQ_OP_WRITE_ZEROES))
177 return q->limits.max_write_zeroes_sectors;
178
179 return q->limits.max_sectors;
180}
181
182#ifdef CONFIG_BLK_DEV_INTEGRITY
183void blk_flush_integrity(void);
184bool __bio_integrity_endio(struct bio *);
185void bio_integrity_free(struct bio *bio);
186static inline bool bio_integrity_endio(struct bio *bio)
187{
188 if (bio_integrity(bio))
189 return __bio_integrity_endio(bio);
190 return true;
191}
192
193bool blk_integrity_merge_rq(struct request_queue *, struct request *,
194 struct request *);
195bool blk_integrity_merge_bio(struct request_queue *, struct request *,
196 struct bio *);
197
198static inline bool integrity_req_gap_back_merge(struct request *req,
199 struct bio *next)
200{
201 struct bio_integrity_payload *bip = bio_integrity(req->bio);
202 struct bio_integrity_payload *bip_next = bio_integrity(next);
203
204 return bvec_gap_to_prev(&req->q->limits,
205 &bip->bip_vec[bip->bip_vcnt - 1],
206 bip_next->bip_vec[0].bv_offset);
207}
208
209static inline bool integrity_req_gap_front_merge(struct request *req,
210 struct bio *bio)
211{
212 struct bio_integrity_payload *bip = bio_integrity(bio);
213 struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
214
215 return bvec_gap_to_prev(&req->q->limits,
216 &bip->bip_vec[bip->bip_vcnt - 1],
217 bip_next->bip_vec[0].bv_offset);
218}
219
220extern const struct attribute_group blk_integrity_attr_group;
221#else /* CONFIG_BLK_DEV_INTEGRITY */
222static inline bool blk_integrity_merge_rq(struct request_queue *rq,
223 struct request *r1, struct request *r2)
224{
225 return true;
226}
227static inline bool blk_integrity_merge_bio(struct request_queue *rq,
228 struct request *r, struct bio *b)
229{
230 return true;
231}
232static inline bool integrity_req_gap_back_merge(struct request *req,
233 struct bio *next)
234{
235 return false;
236}
237static inline bool integrity_req_gap_front_merge(struct request *req,
238 struct bio *bio)
239{
240 return false;
241}
242
243static inline void blk_flush_integrity(void)
244{
245}
246static inline bool bio_integrity_endio(struct bio *bio)
247{
248 return true;
249}
250static inline void bio_integrity_free(struct bio *bio)
251{
252}
253#endif /* CONFIG_BLK_DEV_INTEGRITY */
254
255unsigned long blk_rq_timeout(unsigned long timeout);
256void blk_add_timer(struct request *req);
257
258bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
259 unsigned int nr_segs);
260bool blk_bio_list_merge(struct request_queue *q, struct list_head *list,
261 struct bio *bio, unsigned int nr_segs);
262
263/*
264 * Plug flush limits
265 */
266#define BLK_MAX_REQUEST_COUNT 32
267#define BLK_PLUG_FLUSH_SIZE (128 * 1024)
268
269/*
270 * Internal elevator interface
271 */
272#define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
273
274bool blk_insert_flush(struct request *rq);
275
276int elevator_switch(struct request_queue *q, struct elevator_type *new_e);
277void elevator_disable(struct request_queue *q);
278void elevator_exit(struct request_queue *q);
279int elv_register_queue(struct request_queue *q, bool uevent);
280void elv_unregister_queue(struct request_queue *q);
281
282ssize_t part_size_show(struct device *dev, struct device_attribute *attr,
283 char *buf);
284ssize_t part_stat_show(struct device *dev, struct device_attribute *attr,
285 char *buf);
286ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
287 char *buf);
288ssize_t part_fail_show(struct device *dev, struct device_attribute *attr,
289 char *buf);
290ssize_t part_fail_store(struct device *dev, struct device_attribute *attr,
291 const char *buf, size_t count);
292ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
293ssize_t part_timeout_store(struct device *, struct device_attribute *,
294 const char *, size_t);
295
296static inline bool bio_may_exceed_limits(struct bio *bio,
297 const struct queue_limits *lim)
298{
299 switch (bio_op(bio)) {
300 case REQ_OP_DISCARD:
301 case REQ_OP_SECURE_ERASE:
302 case REQ_OP_WRITE_ZEROES:
303 return true; /* non-trivial splitting decisions */
304 default:
305 break;
306 }
307
308 /*
309 * All drivers must accept single-segments bios that are <= PAGE_SIZE.
310 * This is a quick and dirty check that relies on the fact that
311 * bi_io_vec[0] is always valid if a bio has data. The check might
312 * lead to occasional false negatives when bios are cloned, but compared
313 * to the performance impact of cloned bios themselves the loop below
314 * doesn't matter anyway.
315 */
316 return lim->chunk_sectors || bio->bi_vcnt != 1 ||
317 bio->bi_io_vec->bv_len + bio->bi_io_vec->bv_offset > PAGE_SIZE;
318}
319
320struct bio *__bio_split_to_limits(struct bio *bio,
321 const struct queue_limits *lim,
322 unsigned int *nr_segs);
323int ll_back_merge_fn(struct request *req, struct bio *bio,
324 unsigned int nr_segs);
325bool blk_attempt_req_merge(struct request_queue *q, struct request *rq,
326 struct request *next);
327unsigned int blk_recalc_rq_segments(struct request *rq);
328void blk_rq_set_mixed_merge(struct request *rq);
329bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
330enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
331
332void blk_set_default_limits(struct queue_limits *lim);
333int blk_dev_init(void);
334
335/*
336 * Contribute to IO statistics IFF:
337 *
338 * a) it's attached to a gendisk, and
339 * b) the queue had IO stats enabled when this request was started
340 */
341static inline bool blk_do_io_stat(struct request *rq)
342{
343 return (rq->rq_flags & RQF_IO_STAT) && !blk_rq_is_passthrough(rq);
344}
345
346void update_io_ticks(struct block_device *part, unsigned long now, bool end);
347
348static inline void req_set_nomerge(struct request_queue *q, struct request *req)
349{
350 req->cmd_flags |= REQ_NOMERGE;
351 if (req == q->last_merge)
352 q->last_merge = NULL;
353}
354
355/*
356 * Internal io_context interface
357 */
358struct io_cq *ioc_find_get_icq(struct request_queue *q);
359struct io_cq *ioc_lookup_icq(struct request_queue *q);
360#ifdef CONFIG_BLK_ICQ
361void ioc_clear_queue(struct request_queue *q);
362#else
363static inline void ioc_clear_queue(struct request_queue *q)
364{
365}
366#endif /* CONFIG_BLK_ICQ */
367
368#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
369extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
370extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
371 const char *page, size_t count);
372extern void blk_throtl_bio_endio(struct bio *bio);
373extern void blk_throtl_stat_add(struct request *rq, u64 time);
374#else
375static inline void blk_throtl_bio_endio(struct bio *bio) { }
376static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
377#endif
378
379struct bio *__blk_queue_bounce(struct bio *bio, struct request_queue *q);
380
381static inline bool blk_queue_may_bounce(struct request_queue *q)
382{
383 return IS_ENABLED(CONFIG_BOUNCE) &&
384 q->limits.bounce == BLK_BOUNCE_HIGH &&
385 max_low_pfn >= max_pfn;
386}
387
388static inline struct bio *blk_queue_bounce(struct bio *bio,
389 struct request_queue *q)
390{
391 if (unlikely(blk_queue_may_bounce(q) && bio_has_data(bio)))
392 return __blk_queue_bounce(bio, q);
393 return bio;
394}
395
396#ifdef CONFIG_BLK_DEV_ZONED
397void disk_free_zone_bitmaps(struct gendisk *disk);
398int blkdev_report_zones_ioctl(struct block_device *bdev, unsigned int cmd,
399 unsigned long arg);
400int blkdev_zone_mgmt_ioctl(struct block_device *bdev, blk_mode_t mode,
401 unsigned int cmd, unsigned long arg);
402#else /* CONFIG_BLK_DEV_ZONED */
403static inline void disk_free_zone_bitmaps(struct gendisk *disk) {}
404static inline int blkdev_report_zones_ioctl(struct block_device *bdev,
405 unsigned int cmd, unsigned long arg)
406{
407 return -ENOTTY;
408}
409static inline int blkdev_zone_mgmt_ioctl(struct block_device *bdev,
410 blk_mode_t mode, unsigned int cmd, unsigned long arg)
411{
412 return -ENOTTY;
413}
414#endif /* CONFIG_BLK_DEV_ZONED */
415
416struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
417void bdev_add(struct block_device *bdev, dev_t dev);
418
419int blk_alloc_ext_minor(void);
420void blk_free_ext_minor(unsigned int minor);
421#define ADDPART_FLAG_NONE 0
422#define ADDPART_FLAG_RAID 1
423#define ADDPART_FLAG_WHOLEDISK 2
424int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
425 sector_t length);
426int bdev_del_partition(struct gendisk *disk, int partno);
427int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
428 sector_t length);
429void drop_partition(struct block_device *part);
430
431void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors);
432
433struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
434 struct lock_class_key *lkclass);
435
436int bio_add_hw_page(struct request_queue *q, struct bio *bio,
437 struct page *page, unsigned int len, unsigned int offset,
438 unsigned int max_sectors, bool *same_page);
439
440/*
441 * Clean up a page appropriately, where the page may be pinned, may have a
442 * ref taken on it or neither.
443 */
444static inline void bio_release_page(struct bio *bio, struct page *page)
445{
446 if (bio_flagged(bio, BIO_PAGE_PINNED))
447 unpin_user_page(page);
448}
449
450struct request_queue *blk_alloc_queue(int node_id);
451
452int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode);
453
454int disk_alloc_events(struct gendisk *disk);
455void disk_add_events(struct gendisk *disk);
456void disk_del_events(struct gendisk *disk);
457void disk_release_events(struct gendisk *disk);
458void disk_block_events(struct gendisk *disk);
459void disk_unblock_events(struct gendisk *disk);
460void disk_flush_events(struct gendisk *disk, unsigned int mask);
461extern struct device_attribute dev_attr_events;
462extern struct device_attribute dev_attr_events_async;
463extern struct device_attribute dev_attr_events_poll_msecs;
464
465extern struct attribute_group blk_trace_attr_group;
466
467blk_mode_t file_to_blk_mode(struct file *file);
468int truncate_bdev_range(struct block_device *bdev, blk_mode_t mode,
469 loff_t lstart, loff_t lend);
470long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);
471long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);
472
473extern const struct address_space_operations def_blk_aops;
474
475int disk_register_independent_access_ranges(struct gendisk *disk);
476void disk_unregister_independent_access_ranges(struct gendisk *disk);
477
478#ifdef CONFIG_FAIL_MAKE_REQUEST
479bool should_fail_request(struct block_device *part, unsigned int bytes);
480#else /* CONFIG_FAIL_MAKE_REQUEST */
481static inline bool should_fail_request(struct block_device *part,
482 unsigned int bytes)
483{
484 return false;
485}
486#endif /* CONFIG_FAIL_MAKE_REQUEST */
487
488/*
489 * Optimized request reference counting. Ideally we'd make timeouts be more
490 * clever, as that's the only reason we need references at all... But until
491 * this happens, this is faster than using refcount_t. Also see:
492 *
493 * abc54d634334 ("io_uring: switch to atomic_t for io_kiocb reference count")
494 */
495#define req_ref_zero_or_close_to_overflow(req) \
496 ((unsigned int) atomic_read(&(req->ref)) + 127u <= 127u)
497
498static inline bool req_ref_inc_not_zero(struct request *req)
499{
500 return atomic_inc_not_zero(&req->ref);
501}
502
503static inline bool req_ref_put_and_test(struct request *req)
504{
505 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
506 return atomic_dec_and_test(&req->ref);
507}
508
509static inline void req_ref_set(struct request *req, int value)
510{
511 atomic_set(&req->ref, value);
512}
513
514static inline int req_ref_read(struct request *req)
515{
516 return atomic_read(&req->ref);
517}
518
519#endif /* BLK_INTERNAL_H */
1#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
4#include <linux/idr.h>
5#include <linux/blk-mq.h>
6#include "blk-mq.h"
7
8/* Amount of time in which a process may batch requests */
9#define BLK_BATCH_TIME (HZ/50UL)
10
11/* Number of requests a "batching" process may submit */
12#define BLK_BATCH_REQ 32
13
14/* Max future timer expiry for timeouts */
15#define BLK_MAX_TIMEOUT (5 * HZ)
16
17struct blk_flush_queue {
18 unsigned int flush_queue_delayed:1;
19 unsigned int flush_pending_idx:1;
20 unsigned int flush_running_idx:1;
21 unsigned long flush_pending_since;
22 struct list_head flush_queue[2];
23 struct list_head flush_data_in_flight;
24 struct request *flush_rq;
25
26 /*
27 * flush_rq shares tag with this rq, both can't be active
28 * at the same time
29 */
30 struct request *orig_rq;
31 spinlock_t mq_flush_lock;
32};
33
34extern struct kmem_cache *blk_requestq_cachep;
35extern struct kmem_cache *request_cachep;
36extern struct kobj_type blk_queue_ktype;
37extern struct ida blk_queue_ida;
38
39static inline struct blk_flush_queue *blk_get_flush_queue(
40 struct request_queue *q, struct blk_mq_ctx *ctx)
41{
42 struct blk_mq_hw_ctx *hctx;
43
44 if (!q->mq_ops)
45 return q->fq;
46
47 hctx = q->mq_ops->map_queue(q, ctx->cpu);
48
49 return hctx->fq;
50}
51
52static inline void __blk_get_queue(struct request_queue *q)
53{
54 kobject_get(&q->kobj);
55}
56
57struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
58 int node, int cmd_size);
59void blk_free_flush_queue(struct blk_flush_queue *q);
60
61int blk_init_rl(struct request_list *rl, struct request_queue *q,
62 gfp_t gfp_mask);
63void blk_exit_rl(struct request_list *rl);
64void init_request_from_bio(struct request *req, struct bio *bio);
65void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
66 struct bio *bio);
67int blk_rq_append_bio(struct request_queue *q, struct request *rq,
68 struct bio *bio);
69void blk_queue_bypass_start(struct request_queue *q);
70void blk_queue_bypass_end(struct request_queue *q);
71void blk_dequeue_request(struct request *rq);
72void __blk_queue_free_tags(struct request_queue *q);
73bool __blk_end_bidi_request(struct request *rq, int error,
74 unsigned int nr_bytes, unsigned int bidi_bytes);
75void blk_freeze_queue(struct request_queue *q);
76
77static inline void blk_queue_enter_live(struct request_queue *q)
78{
79 /*
80 * Given that running in generic_make_request() context
81 * guarantees that a live reference against q_usage_counter has
82 * been established, further references under that same context
83 * need not check that the queue has been frozen (marked dead).
84 */
85 percpu_ref_get(&q->q_usage_counter);
86}
87
88#ifdef CONFIG_BLK_DEV_INTEGRITY
89void blk_flush_integrity(void);
90#else
91static inline void blk_flush_integrity(void)
92{
93}
94#endif
95
96void blk_timeout_work(struct work_struct *work);
97unsigned long blk_rq_timeout(unsigned long timeout);
98void blk_add_timer(struct request *req);
99void blk_delete_timer(struct request *);
100
101
102bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
103 struct bio *bio);
104bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
105 struct bio *bio);
106bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
107 unsigned int *request_count,
108 struct request **same_queue_rq);
109unsigned int blk_plug_queued_count(struct request_queue *q);
110
111void blk_account_io_start(struct request *req, bool new_io);
112void blk_account_io_completion(struct request *req, unsigned int bytes);
113void blk_account_io_done(struct request *req);
114
115/*
116 * Internal atomic flags for request handling
117 */
118enum rq_atomic_flags {
119 REQ_ATOM_COMPLETE = 0,
120 REQ_ATOM_STARTED,
121};
122
123/*
124 * EH timer and IO completion will both attempt to 'grab' the request, make
125 * sure that only one of them succeeds
126 */
127static inline int blk_mark_rq_complete(struct request *rq)
128{
129 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
130}
131
132static inline void blk_clear_rq_complete(struct request *rq)
133{
134 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
135}
136
137/*
138 * Internal elevator interface
139 */
140#define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
141
142void blk_insert_flush(struct request *rq);
143
144static inline struct request *__elv_next_request(struct request_queue *q)
145{
146 struct request *rq;
147 struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
148
149 while (1) {
150 if (!list_empty(&q->queue_head)) {
151 rq = list_entry_rq(q->queue_head.next);
152 return rq;
153 }
154
155 /*
156 * Flush request is running and flush request isn't queueable
157 * in the drive, we can hold the queue till flush request is
158 * finished. Even we don't do this, driver can't dispatch next
159 * requests and will requeue them. And this can improve
160 * throughput too. For example, we have request flush1, write1,
161 * flush 2. flush1 is dispatched, then queue is hold, write1
162 * isn't inserted to queue. After flush1 is finished, flush2
163 * will be dispatched. Since disk cache is already clean,
164 * flush2 will be finished very soon, so looks like flush2 is
165 * folded to flush1.
166 * Since the queue is hold, a flag is set to indicate the queue
167 * should be restarted later. Please see flush_end_io() for
168 * details.
169 */
170 if (fq->flush_pending_idx != fq->flush_running_idx &&
171 !queue_flush_queueable(q)) {
172 fq->flush_queue_delayed = 1;
173 return NULL;
174 }
175 if (unlikely(blk_queue_bypass(q)) ||
176 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
177 return NULL;
178 }
179}
180
181static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
182{
183 struct elevator_queue *e = q->elevator;
184
185 if (e->type->ops.elevator_activate_req_fn)
186 e->type->ops.elevator_activate_req_fn(q, rq);
187}
188
189static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
190{
191 struct elevator_queue *e = q->elevator;
192
193 if (e->type->ops.elevator_deactivate_req_fn)
194 e->type->ops.elevator_deactivate_req_fn(q, rq);
195}
196
197#ifdef CONFIG_FAIL_IO_TIMEOUT
198int blk_should_fake_timeout(struct request_queue *);
199ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
200ssize_t part_timeout_store(struct device *, struct device_attribute *,
201 const char *, size_t);
202#else
203static inline int blk_should_fake_timeout(struct request_queue *q)
204{
205 return 0;
206}
207#endif
208
209int ll_back_merge_fn(struct request_queue *q, struct request *req,
210 struct bio *bio);
211int ll_front_merge_fn(struct request_queue *q, struct request *req,
212 struct bio *bio);
213int attempt_back_merge(struct request_queue *q, struct request *rq);
214int attempt_front_merge(struct request_queue *q, struct request *rq);
215int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
216 struct request *next);
217void blk_recalc_rq_segments(struct request *rq);
218void blk_rq_set_mixed_merge(struct request *rq);
219bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
220int blk_try_merge(struct request *rq, struct bio *bio);
221
222void blk_queue_congestion_threshold(struct request_queue *q);
223
224int blk_dev_init(void);
225
226
227/*
228 * Return the threshold (number of used requests) at which the queue is
229 * considered to be congested. It include a little hysteresis to keep the
230 * context switch rate down.
231 */
232static inline int queue_congestion_on_threshold(struct request_queue *q)
233{
234 return q->nr_congestion_on;
235}
236
237/*
238 * The threshold at which a queue is considered to be uncongested
239 */
240static inline int queue_congestion_off_threshold(struct request_queue *q)
241{
242 return q->nr_congestion_off;
243}
244
245extern int blk_update_nr_requests(struct request_queue *, unsigned int);
246
247/*
248 * Contribute to IO statistics IFF:
249 *
250 * a) it's attached to a gendisk, and
251 * b) the queue had IO stats enabled when this request was started, and
252 * c) it's a file system request
253 */
254static inline int blk_do_io_stat(struct request *rq)
255{
256 return rq->rq_disk &&
257 (rq->cmd_flags & REQ_IO_STAT) &&
258 (rq->cmd_type == REQ_TYPE_FS);
259}
260
261/*
262 * Internal io_context interface
263 */
264void get_io_context(struct io_context *ioc);
265struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
266struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
267 gfp_t gfp_mask);
268void ioc_clear_queue(struct request_queue *q);
269
270int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
271
272/**
273 * create_io_context - try to create task->io_context
274 * @gfp_mask: allocation mask
275 * @node: allocation node
276 *
277 * If %current->io_context is %NULL, allocate a new io_context and install
278 * it. Returns the current %current->io_context which may be %NULL if
279 * allocation failed.
280 *
281 * Note that this function can't be called with IRQ disabled because
282 * task_lock which protects %current->io_context is IRQ-unsafe.
283 */
284static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
285{
286 WARN_ON_ONCE(irqs_disabled());
287 if (unlikely(!current->io_context))
288 create_task_io_context(current, gfp_mask, node);
289 return current->io_context;
290}
291
292/*
293 * Internal throttling interface
294 */
295#ifdef CONFIG_BLK_DEV_THROTTLING
296extern void blk_throtl_drain(struct request_queue *q);
297extern int blk_throtl_init(struct request_queue *q);
298extern void blk_throtl_exit(struct request_queue *q);
299#else /* CONFIG_BLK_DEV_THROTTLING */
300static inline void blk_throtl_drain(struct request_queue *q) { }
301static inline int blk_throtl_init(struct request_queue *q) { return 0; }
302static inline void blk_throtl_exit(struct request_queue *q) { }
303#endif /* CONFIG_BLK_DEV_THROTTLING */
304
305#endif /* BLK_INTERNAL_H */