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Linux/block/blk.h

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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 "blk-mq.h"
  8 
  9 /* Amount of time in which a process may batch requests */
 10 #define BLK_BATCH_TIME  (HZ/50UL)
 11 
 12 /* Number of requests a "batching" process may submit */
 13 #define BLK_BATCH_REQ   32
 14 
 15 /* Max future timer expiry for timeouts */
 16 #define BLK_MAX_TIMEOUT         (5 * HZ)
 17 
 18 #ifdef CONFIG_DEBUG_FS
 19 extern struct dentry *blk_debugfs_root;
 20 #endif
 21 
 22 struct blk_flush_queue {
 23         unsigned int            flush_queue_delayed:1;
 24         unsigned int            flush_pending_idx:1;
 25         unsigned int            flush_running_idx:1;
 26         unsigned long           flush_pending_since;
 27         struct list_head        flush_queue[2];
 28         struct list_head        flush_data_in_flight;
 29         struct request          *flush_rq;
 30 
 31         /*
 32          * flush_rq shares tag with this rq, both can't be active
 33          * at the same time
 34          */
 35         struct request          *orig_rq;
 36         spinlock_t              mq_flush_lock;
 37 };
 38 
 39 extern struct kmem_cache *blk_requestq_cachep;
 40 extern struct kmem_cache *request_cachep;
 41 extern struct kobj_type blk_queue_ktype;
 42 extern struct ida blk_queue_ida;
 43 
 44 /*
 45  * @q->queue_lock is set while a queue is being initialized. Since we know
 46  * that no other threads access the queue object before @q->queue_lock has
 47  * been set, it is safe to manipulate queue flags without holding the
 48  * queue_lock if @q->queue_lock == NULL. See also blk_alloc_queue_node() and
 49  * blk_init_allocated_queue().
 50  */
 51 static inline void queue_lockdep_assert_held(struct request_queue *q)
 52 {
 53         if (q->queue_lock)
 54                 lockdep_assert_held(q->queue_lock);
 55 }
 56 
 57 static inline void queue_flag_set_unlocked(unsigned int flag,
 58                                            struct request_queue *q)
 59 {
 60         if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
 61             kref_read(&q->kobj.kref))
 62                 lockdep_assert_held(q->queue_lock);
 63         __set_bit(flag, &q->queue_flags);
 64 }
 65 
 66 static inline void queue_flag_clear_unlocked(unsigned int flag,
 67                                              struct request_queue *q)
 68 {
 69         if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
 70             kref_read(&q->kobj.kref))
 71                 lockdep_assert_held(q->queue_lock);
 72         __clear_bit(flag, &q->queue_flags);
 73 }
 74 
 75 static inline int queue_flag_test_and_clear(unsigned int flag,
 76                                             struct request_queue *q)
 77 {
 78         queue_lockdep_assert_held(q);
 79 
 80         if (test_bit(flag, &q->queue_flags)) {
 81                 __clear_bit(flag, &q->queue_flags);
 82                 return 1;
 83         }
 84 
 85         return 0;
 86 }
 87 
 88 static inline int queue_flag_test_and_set(unsigned int flag,
 89                                           struct request_queue *q)
 90 {
 91         queue_lockdep_assert_held(q);
 92 
 93         if (!test_bit(flag, &q->queue_flags)) {
 94                 __set_bit(flag, &q->queue_flags);
 95                 return 0;
 96         }
 97 
 98         return 1;
 99 }
100 
101 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
102 {
103         queue_lockdep_assert_held(q);
104         __set_bit(flag, &q->queue_flags);
105 }
106 
107 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
108 {
109         queue_lockdep_assert_held(q);
110         __clear_bit(flag, &q->queue_flags);
111 }
112 
113 static inline struct blk_flush_queue *blk_get_flush_queue(
114                 struct request_queue *q, struct blk_mq_ctx *ctx)
115 {
116         if (q->mq_ops)
117                 return blk_mq_map_queue(q, ctx->cpu)->fq;
118         return q->fq;
119 }
120 
121 static inline void __blk_get_queue(struct request_queue *q)
122 {
123         kobject_get(&q->kobj);
124 }
125 
126 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
127                 int node, int cmd_size);
128 void blk_free_flush_queue(struct blk_flush_queue *q);
129 
130 int blk_init_rl(struct request_list *rl, struct request_queue *q,
131                 gfp_t gfp_mask);
132 void blk_exit_rl(struct request_queue *q, struct request_list *rl);
133 void blk_exit_queue(struct request_queue *q);
134 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
135                         struct bio *bio);
136 void blk_queue_bypass_start(struct request_queue *q);
137 void blk_queue_bypass_end(struct request_queue *q);
138 void __blk_queue_free_tags(struct request_queue *q);
139 void blk_freeze_queue(struct request_queue *q);
140 
141 static inline void blk_queue_enter_live(struct request_queue *q)
142 {
143         /*
144          * Given that running in generic_make_request() context
145          * guarantees that a live reference against q_usage_counter has
146          * been established, further references under that same context
147          * need not check that the queue has been frozen (marked dead).
148          */
149         percpu_ref_get(&q->q_usage_counter);
150 }
151 
152 #ifdef CONFIG_BLK_DEV_INTEGRITY
153 void blk_flush_integrity(void);
154 bool __bio_integrity_endio(struct bio *);
155 static inline bool bio_integrity_endio(struct bio *bio)
156 {
157         if (bio_integrity(bio))
158                 return __bio_integrity_endio(bio);
159         return true;
160 }
161 #else
162 static inline void blk_flush_integrity(void)
163 {
164 }
165 static inline bool bio_integrity_endio(struct bio *bio)
166 {
167         return true;
168 }
169 #endif
170 
171 void blk_timeout_work(struct work_struct *work);
172 unsigned long blk_rq_timeout(unsigned long timeout);
173 void blk_add_timer(struct request *req);
174 void blk_delete_timer(struct request *);
175 
176 
177 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
178                              struct bio *bio);
179 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
180                             struct bio *bio);
181 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
182                 struct bio *bio);
183 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
184                             unsigned int *request_count,
185                             struct request **same_queue_rq);
186 unsigned int blk_plug_queued_count(struct request_queue *q);
187 
188 void blk_account_io_start(struct request *req, bool new_io);
189 void blk_account_io_completion(struct request *req, unsigned int bytes);
190 void blk_account_io_done(struct request *req, u64 now);
191 
192 /*
193  * EH timer and IO completion will both attempt to 'grab' the request, make
194  * sure that only one of them succeeds. Steal the bottom bit of the
195  * __deadline field for this.
196  */
197 static inline int blk_mark_rq_complete(struct request *rq)
198 {
199         return test_and_set_bit(0, &rq->__deadline);
200 }
201 
202 static inline void blk_clear_rq_complete(struct request *rq)
203 {
204         clear_bit(0, &rq->__deadline);
205 }
206 
207 static inline bool blk_rq_is_complete(struct request *rq)
208 {
209         return test_bit(0, &rq->__deadline);
210 }
211 
212 /*
213  * Internal elevator interface
214  */
215 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
216 
217 void blk_insert_flush(struct request *rq);
218 
219 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
220 {
221         struct elevator_queue *e = q->elevator;
222 
223         if (e->type->ops.sq.elevator_activate_req_fn)
224                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
225 }
226 
227 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
228 {
229         struct elevator_queue *e = q->elevator;
230 
231         if (e->type->ops.sq.elevator_deactivate_req_fn)
232                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
233 }
234 
235 int elevator_init(struct request_queue *);
236 int elevator_init_mq(struct request_queue *q);
237 void elevator_exit(struct request_queue *, struct elevator_queue *);
238 int elv_register_queue(struct request_queue *q);
239 void elv_unregister_queue(struct request_queue *q);
240 
241 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
242 
243 #ifdef CONFIG_FAIL_IO_TIMEOUT
244 int blk_should_fake_timeout(struct request_queue *);
245 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
246 ssize_t part_timeout_store(struct device *, struct device_attribute *,
247                                 const char *, size_t);
248 #else
249 static inline int blk_should_fake_timeout(struct request_queue *q)
250 {
251         return 0;
252 }
253 #endif
254 
255 int ll_back_merge_fn(struct request_queue *q, struct request *req,
256                      struct bio *bio);
257 int ll_front_merge_fn(struct request_queue *q, struct request *req, 
258                       struct bio *bio);
259 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
260 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
261 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
262                                 struct request *next);
263 void blk_recalc_rq_segments(struct request *rq);
264 void blk_rq_set_mixed_merge(struct request *rq);
265 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
266 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
267 
268 void blk_queue_congestion_threshold(struct request_queue *q);
269 
270 int blk_dev_init(void);
271 
272 
273 /*
274  * Return the threshold (number of used requests) at which the queue is
275  * considered to be congested.  It include a little hysteresis to keep the
276  * context switch rate down.
277  */
278 static inline int queue_congestion_on_threshold(struct request_queue *q)
279 {
280         return q->nr_congestion_on;
281 }
282 
283 /*
284  * The threshold at which a queue is considered to be uncongested
285  */
286 static inline int queue_congestion_off_threshold(struct request_queue *q)
287 {
288         return q->nr_congestion_off;
289 }
290 
291 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
292 
293 /*
294  * Contribute to IO statistics IFF:
295  *
296  *      a) it's attached to a gendisk, and
297  *      b) the queue had IO stats enabled when this request was started, and
298  *      c) it's a file system request
299  */
300 static inline int blk_do_io_stat(struct request *rq)
301 {
302         return rq->rq_disk &&
303                (rq->rq_flags & RQF_IO_STAT) &&
304                 !blk_rq_is_passthrough(rq);
305 }
306 
307 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
308 {
309         req->cmd_flags |= REQ_NOMERGE;
310         if (req == q->last_merge)
311                 q->last_merge = NULL;
312 }
313 
314 /*
315  * Steal a bit from this field for legacy IO path atomic IO marking. Note that
316  * setting the deadline clears the bottom bit, potentially clearing the
317  * completed bit. The user has to be OK with this (current ones are fine).
318  */
319 static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
320 {
321         rq->__deadline = time & ~0x1UL;
322 }
323 
324 static inline unsigned long blk_rq_deadline(struct request *rq)
325 {
326         return rq->__deadline & ~0x1UL;
327 }
328 
329 /*
330  * The max size one bio can handle is UINT_MAX becasue bvec_iter.bi_size
331  * is defined as 'unsigned int', meantime it has to aligned to with logical
332  * block size which is the minimum accepted unit by hardware.
333  */
334 static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
335 {
336         return round_down(UINT_MAX, queue_logical_block_size(q)) >> 9;
337 }
338 
339 /*
340  * Internal io_context interface
341  */
342 void get_io_context(struct io_context *ioc);
343 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
344 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
345                              gfp_t gfp_mask);
346 void ioc_clear_queue(struct request_queue *q);
347 
348 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
349 
350 /**
351  * rq_ioc - determine io_context for request allocation
352  * @bio: request being allocated is for this bio (can be %NULL)
353  *
354  * Determine io_context to use for request allocation for @bio.  May return
355  * %NULL if %current->io_context doesn't exist.
356  */
357 static inline struct io_context *rq_ioc(struct bio *bio)
358 {
359 #ifdef CONFIG_BLK_CGROUP
360         if (bio && bio->bi_ioc)
361                 return bio->bi_ioc;
362 #endif
363         return current->io_context;
364 }
365 
366 /**
367  * create_io_context - try to create task->io_context
368  * @gfp_mask: allocation mask
369  * @node: allocation node
370  *
371  * If %current->io_context is %NULL, allocate a new io_context and install
372  * it.  Returns the current %current->io_context which may be %NULL if
373  * allocation failed.
374  *
375  * Note that this function can't be called with IRQ disabled because
376  * task_lock which protects %current->io_context is IRQ-unsafe.
377  */
378 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
379 {
380         WARN_ON_ONCE(irqs_disabled());
381         if (unlikely(!current->io_context))
382                 create_task_io_context(current, gfp_mask, node);
383         return current->io_context;
384 }
385 
386 /*
387  * Internal throttling interface
388  */
389 #ifdef CONFIG_BLK_DEV_THROTTLING
390 extern void blk_throtl_drain(struct request_queue *q);
391 extern int blk_throtl_init(struct request_queue *q);
392 extern void blk_throtl_exit(struct request_queue *q);
393 extern void blk_throtl_register_queue(struct request_queue *q);
394 #else /* CONFIG_BLK_DEV_THROTTLING */
395 static inline void blk_throtl_drain(struct request_queue *q) { }
396 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
397 static inline void blk_throtl_exit(struct request_queue *q) { }
398 static inline void blk_throtl_register_queue(struct request_queue *q) { }
399 #endif /* CONFIG_BLK_DEV_THROTTLING */
400 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
401 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
402 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
403         const char *page, size_t count);
404 extern void blk_throtl_bio_endio(struct bio *bio);
405 extern void blk_throtl_stat_add(struct request *rq, u64 time);
406 #else
407 static inline void blk_throtl_bio_endio(struct bio *bio) { }
408 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
409 #endif
410 
411 #ifdef CONFIG_BOUNCE
412 extern int init_emergency_isa_pool(void);
413 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
414 #else
415 static inline int init_emergency_isa_pool(void)
416 {
417         return 0;
418 }
419 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
420 {
421 }
422 #endif /* CONFIG_BOUNCE */
423 
424 extern void blk_drain_queue(struct request_queue *q);
425 
426 #endif /* BLK_INTERNAL_H */
427 

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