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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/idr.h>
6#include <linux/blk-mq.h>
7#include <linux/part_stat.h>
8#include <linux/blk-crypto.h>
9#include <xen/xen.h>
10#include "blk-crypto-internal.h"
11#include "blk-mq.h"
12#include "blk-mq-sched.h"
13
14/* Max future timer expiry for timeouts */
15#define BLK_MAX_TIMEOUT (5 * HZ)
16
17extern struct dentry *blk_debugfs_root;
18
19struct blk_flush_queue {
20 unsigned int flush_pending_idx:1;
21 unsigned int flush_running_idx:1;
22 blk_status_t rq_status;
23 unsigned long flush_pending_since;
24 struct list_head flush_queue[2];
25 struct list_head flush_data_in_flight;
26 struct request *flush_rq;
27
28 struct lock_class_key key;
29 spinlock_t mq_flush_lock;
30};
31
32extern struct kmem_cache *blk_requestq_cachep;
33extern struct kobj_type blk_queue_ktype;
34extern struct ida blk_queue_ida;
35
36static inline struct blk_flush_queue *
37blk_get_flush_queue(struct request_queue *q, struct blk_mq_ctx *ctx)
38{
39 return blk_mq_map_queue(q, REQ_OP_FLUSH, ctx)->fq;
40}
41
42static inline void __blk_get_queue(struct request_queue *q)
43{
44 kobject_get(&q->kobj);
45}
46
47static inline bool
48is_flush_rq(struct request *req, struct blk_mq_hw_ctx *hctx)
49{
50 return hctx->fq->flush_rq == req;
51}
52
53struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
54 gfp_t flags);
55void blk_free_flush_queue(struct blk_flush_queue *q);
56
57void blk_freeze_queue(struct request_queue *q);
58
59static inline bool biovec_phys_mergeable(struct request_queue *q,
60 struct bio_vec *vec1, struct bio_vec *vec2)
61{
62 unsigned long mask = queue_segment_boundary(q);
63 phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset;
64 phys_addr_t addr2 = page_to_phys(vec2->bv_page) + vec2->bv_offset;
65
66 if (addr1 + vec1->bv_len != addr2)
67 return false;
68 if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page))
69 return false;
70 if ((addr1 | mask) != ((addr2 + vec2->bv_len - 1) | mask))
71 return false;
72 return true;
73}
74
75static inline bool __bvec_gap_to_prev(struct request_queue *q,
76 struct bio_vec *bprv, unsigned int offset)
77{
78 return (offset & queue_virt_boundary(q)) ||
79 ((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
80}
81
82/*
83 * Check if adding a bio_vec after bprv with offset would create a gap in
84 * the SG list. Most drivers don't care about this, but some do.
85 */
86static inline bool bvec_gap_to_prev(struct request_queue *q,
87 struct bio_vec *bprv, unsigned int offset)
88{
89 if (!queue_virt_boundary(q))
90 return false;
91 return __bvec_gap_to_prev(q, bprv, offset);
92}
93
94static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio,
95 unsigned int nr_segs)
96{
97 rq->nr_phys_segments = nr_segs;
98 rq->__data_len = bio->bi_iter.bi_size;
99 rq->bio = rq->biotail = bio;
100 rq->ioprio = bio_prio(bio);
101
102 if (bio->bi_disk)
103 rq->rq_disk = bio->bi_disk;
104}
105
106#ifdef CONFIG_BLK_DEV_INTEGRITY
107void blk_flush_integrity(void);
108bool __bio_integrity_endio(struct bio *);
109void bio_integrity_free(struct bio *bio);
110static inline bool bio_integrity_endio(struct bio *bio)
111{
112 if (bio_integrity(bio))
113 return __bio_integrity_endio(bio);
114 return true;
115}
116
117static inline bool integrity_req_gap_back_merge(struct request *req,
118 struct bio *next)
119{
120 struct bio_integrity_payload *bip = bio_integrity(req->bio);
121 struct bio_integrity_payload *bip_next = bio_integrity(next);
122
123 return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
124 bip_next->bip_vec[0].bv_offset);
125}
126
127static inline bool integrity_req_gap_front_merge(struct request *req,
128 struct bio *bio)
129{
130 struct bio_integrity_payload *bip = bio_integrity(bio);
131 struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
132
133 return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
134 bip_next->bip_vec[0].bv_offset);
135}
136
137void blk_integrity_add(struct gendisk *);
138void blk_integrity_del(struct gendisk *);
139#else /* CONFIG_BLK_DEV_INTEGRITY */
140static inline bool integrity_req_gap_back_merge(struct request *req,
141 struct bio *next)
142{
143 return false;
144}
145static inline bool integrity_req_gap_front_merge(struct request *req,
146 struct bio *bio)
147{
148 return false;
149}
150
151static inline void blk_flush_integrity(void)
152{
153}
154static inline bool bio_integrity_endio(struct bio *bio)
155{
156 return true;
157}
158static inline void bio_integrity_free(struct bio *bio)
159{
160}
161static inline void blk_integrity_add(struct gendisk *disk)
162{
163}
164static inline void blk_integrity_del(struct gendisk *disk)
165{
166}
167#endif /* CONFIG_BLK_DEV_INTEGRITY */
168
169unsigned long blk_rq_timeout(unsigned long timeout);
170void blk_add_timer(struct request *req);
171
172bool bio_attempt_front_merge(struct request *req, struct bio *bio,
173 unsigned int nr_segs);
174bool bio_attempt_back_merge(struct request *req, struct bio *bio,
175 unsigned int nr_segs);
176bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
177 struct bio *bio);
178bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
179 unsigned int nr_segs, struct request **same_queue_rq);
180
181void blk_account_io_start(struct request *req);
182void blk_account_io_done(struct request *req, u64 now);
183
184/*
185 * Internal elevator interface
186 */
187#define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
188
189void blk_insert_flush(struct request *rq);
190
191void elevator_init_mq(struct request_queue *q);
192int elevator_switch_mq(struct request_queue *q,
193 struct elevator_type *new_e);
194void __elevator_exit(struct request_queue *, struct elevator_queue *);
195int elv_register_queue(struct request_queue *q, bool uevent);
196void elv_unregister_queue(struct request_queue *q);
197
198static inline void elevator_exit(struct request_queue *q,
199 struct elevator_queue *e)
200{
201 lockdep_assert_held(&q->sysfs_lock);
202
203 blk_mq_sched_free_requests(q);
204 __elevator_exit(q, e);
205}
206
207struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
208
209ssize_t part_size_show(struct device *dev, struct device_attribute *attr,
210 char *buf);
211ssize_t part_stat_show(struct device *dev, struct device_attribute *attr,
212 char *buf);
213ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
214 char *buf);
215ssize_t part_fail_show(struct device *dev, struct device_attribute *attr,
216 char *buf);
217ssize_t part_fail_store(struct device *dev, struct device_attribute *attr,
218 const char *buf, size_t count);
219ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
220ssize_t part_timeout_store(struct device *, struct device_attribute *,
221 const char *, size_t);
222
223void __blk_queue_split(struct bio **bio, unsigned int *nr_segs);
224int ll_back_merge_fn(struct request *req, struct bio *bio,
225 unsigned int nr_segs);
226int ll_front_merge_fn(struct request *req, struct bio *bio,
227 unsigned int nr_segs);
228struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
229struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
230int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
231 struct request *next);
232unsigned int blk_recalc_rq_segments(struct request *rq);
233void blk_rq_set_mixed_merge(struct request *rq);
234bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
235enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
236
237int blk_dev_init(void);
238
239/*
240 * Contribute to IO statistics IFF:
241 *
242 * a) it's attached to a gendisk, and
243 * b) the queue had IO stats enabled when this request was started
244 */
245static inline bool blk_do_io_stat(struct request *rq)
246{
247 return rq->rq_disk && (rq->rq_flags & RQF_IO_STAT);
248}
249
250static inline void req_set_nomerge(struct request_queue *q, struct request *req)
251{
252 req->cmd_flags |= REQ_NOMERGE;
253 if (req == q->last_merge)
254 q->last_merge = NULL;
255}
256
257/*
258 * The max size one bio can handle is UINT_MAX becasue bvec_iter.bi_size
259 * is defined as 'unsigned int', meantime it has to aligned to with logical
260 * block size which is the minimum accepted unit by hardware.
261 */
262static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
263{
264 return round_down(UINT_MAX, queue_logical_block_size(q)) >> 9;
265}
266
267/*
268 * The max bio size which is aligned to q->limits.discard_granularity. This
269 * is a hint to split large discard bio in generic block layer, then if device
270 * driver needs to split the discard bio into smaller ones, their bi_size can
271 * be very probably and easily aligned to discard_granularity of the device's
272 * queue.
273 */
274static inline unsigned int bio_aligned_discard_max_sectors(
275 struct request_queue *q)
276{
277 return round_down(UINT_MAX, q->limits.discard_granularity) >>
278 SECTOR_SHIFT;
279}
280
281/*
282 * Internal io_context interface
283 */
284void get_io_context(struct io_context *ioc);
285struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
286struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
287 gfp_t gfp_mask);
288void ioc_clear_queue(struct request_queue *q);
289
290int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
291
292/*
293 * Internal throttling interface
294 */
295#ifdef CONFIG_BLK_DEV_THROTTLING
296extern int blk_throtl_init(struct request_queue *q);
297extern void blk_throtl_exit(struct request_queue *q);
298extern void blk_throtl_register_queue(struct request_queue *q);
299bool blk_throtl_bio(struct bio *bio);
300#else /* CONFIG_BLK_DEV_THROTTLING */
301static inline int blk_throtl_init(struct request_queue *q) { return 0; }
302static inline void blk_throtl_exit(struct request_queue *q) { }
303static inline void blk_throtl_register_queue(struct request_queue *q) { }
304static inline bool blk_throtl_bio(struct bio *bio) { return false; }
305#endif /* CONFIG_BLK_DEV_THROTTLING */
306#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
307extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
308extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
309 const char *page, size_t count);
310extern void blk_throtl_bio_endio(struct bio *bio);
311extern void blk_throtl_stat_add(struct request *rq, u64 time);
312#else
313static inline void blk_throtl_bio_endio(struct bio *bio) { }
314static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
315#endif
316
317#ifdef CONFIG_BOUNCE
318extern int init_emergency_isa_pool(void);
319extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
320#else
321static inline int init_emergency_isa_pool(void)
322{
323 return 0;
324}
325static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
326{
327}
328#endif /* CONFIG_BOUNCE */
329
330#ifdef CONFIG_BLK_CGROUP_IOLATENCY
331extern int blk_iolatency_init(struct request_queue *q);
332#else
333static inline int blk_iolatency_init(struct request_queue *q) { return 0; }
334#endif
335
336struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
337
338#ifdef CONFIG_BLK_DEV_ZONED
339void blk_queue_free_zone_bitmaps(struct request_queue *q);
340#else
341static inline void blk_queue_free_zone_bitmaps(struct request_queue *q) {}
342#endif
343
344struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector);
345
346int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
347void blk_free_devt(dev_t devt);
348void blk_invalidate_devt(dev_t devt);
349char *disk_name(struct gendisk *hd, int partno, char *buf);
350#define ADDPART_FLAG_NONE 0
351#define ADDPART_FLAG_RAID 1
352#define ADDPART_FLAG_WHOLEDISK 2
353void delete_partition(struct gendisk *disk, struct hd_struct *part);
354int bdev_add_partition(struct block_device *bdev, int partno,
355 sector_t start, sector_t length);
356int bdev_del_partition(struct block_device *bdev, int partno);
357int bdev_resize_partition(struct block_device *bdev, int partno,
358 sector_t start, sector_t length);
359int disk_expand_part_tbl(struct gendisk *disk, int target);
360int hd_ref_init(struct hd_struct *part);
361
362/* no need to get/put refcount of part0 */
363static inline int hd_struct_try_get(struct hd_struct *part)
364{
365 if (part->partno)
366 return percpu_ref_tryget_live(&part->ref);
367 return 1;
368}
369
370static inline void hd_struct_put(struct hd_struct *part)
371{
372 if (part->partno)
373 percpu_ref_put(&part->ref);
374}
375
376static inline void hd_free_part(struct hd_struct *part)
377{
378 free_percpu(part->dkstats);
379 kfree(part->info);
380 percpu_ref_exit(&part->ref);
381}
382
383/*
384 * Any access of part->nr_sects which is not protected by partition
385 * bd_mutex or gendisk bdev bd_mutex, should be done using this
386 * accessor function.
387 *
388 * Code written along the lines of i_size_read() and i_size_write().
389 * CONFIG_PREEMPTION case optimizes the case of UP kernel with preemption
390 * on.
391 */
392static inline sector_t part_nr_sects_read(struct hd_struct *part)
393{
394#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
395 sector_t nr_sects;
396 unsigned seq;
397 do {
398 seq = read_seqcount_begin(&part->nr_sects_seq);
399 nr_sects = part->nr_sects;
400 } while (read_seqcount_retry(&part->nr_sects_seq, seq));
401 return nr_sects;
402#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
403 sector_t nr_sects;
404
405 preempt_disable();
406 nr_sects = part->nr_sects;
407 preempt_enable();
408 return nr_sects;
409#else
410 return part->nr_sects;
411#endif
412}
413
414/*
415 * Should be called with mutex lock held (typically bd_mutex) of partition
416 * to provide mutual exlusion among writers otherwise seqcount might be
417 * left in wrong state leaving the readers spinning infinitely.
418 */
419static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
420{
421#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
422 preempt_disable();
423 write_seqcount_begin(&part->nr_sects_seq);
424 part->nr_sects = size;
425 write_seqcount_end(&part->nr_sects_seq);
426 preempt_enable();
427#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
428 preempt_disable();
429 part->nr_sects = size;
430 preempt_enable();
431#else
432 part->nr_sects = size;
433#endif
434}
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#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 */