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TOMOYO Linux Cross Reference
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_rq_bio_prep(struct request_queue *q, struct request *rq,
134                         struct bio *bio);
135 void blk_queue_bypass_start(struct request_queue *q);
136 void blk_queue_bypass_end(struct request_queue *q);
137 void __blk_queue_free_tags(struct request_queue *q);
138 void blk_freeze_queue(struct request_queue *q);
139 
140 static inline void blk_queue_enter_live(struct request_queue *q)
141 {
142         /*
143          * Given that running in generic_make_request() context
144          * guarantees that a live reference against q_usage_counter has
145          * been established, further references under that same context
146          * need not check that the queue has been frozen (marked dead).
147          */
148         percpu_ref_get(&q->q_usage_counter);
149 }
150 
151 #ifdef CONFIG_BLK_DEV_INTEGRITY
152 void blk_flush_integrity(void);
153 bool __bio_integrity_endio(struct bio *);
154 static inline bool bio_integrity_endio(struct bio *bio)
155 {
156         if (bio_integrity(bio))
157                 return __bio_integrity_endio(bio);
158         return true;
159 }
160 #else
161 static inline void blk_flush_integrity(void)
162 {
163 }
164 static inline bool bio_integrity_endio(struct bio *bio)
165 {
166         return true;
167 }
168 #endif
169 
170 void blk_timeout_work(struct work_struct *work);
171 unsigned long blk_rq_timeout(unsigned long timeout);
172 void blk_add_timer(struct request *req);
173 void blk_delete_timer(struct request *);
174 
175 
176 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
177                              struct bio *bio);
178 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
179                             struct bio *bio);
180 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
181                 struct bio *bio);
182 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
183                             unsigned int *request_count,
184                             struct request **same_queue_rq);
185 unsigned int blk_plug_queued_count(struct request_queue *q);
186 
187 void blk_account_io_start(struct request *req, bool new_io);
188 void blk_account_io_completion(struct request *req, unsigned int bytes);
189 void blk_account_io_done(struct request *req);
190 
191 /*
192  * EH timer and IO completion will both attempt to 'grab' the request, make
193  * sure that only one of them succeeds. Steal the bottom bit of the
194  * __deadline field for this.
195  */
196 static inline int blk_mark_rq_complete(struct request *rq)
197 {
198         return test_and_set_bit(0, &rq->__deadline);
199 }
200 
201 static inline void blk_clear_rq_complete(struct request *rq)
202 {
203         clear_bit(0, &rq->__deadline);
204 }
205 
206 static inline bool blk_rq_is_complete(struct request *rq)
207 {
208         return test_bit(0, &rq->__deadline);
209 }
210 
211 /*
212  * Internal elevator interface
213  */
214 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
215 
216 void blk_insert_flush(struct request *rq);
217 
218 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
219 {
220         struct elevator_queue *e = q->elevator;
221 
222         if (e->type->ops.sq.elevator_activate_req_fn)
223                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
224 }
225 
226 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
227 {
228         struct elevator_queue *e = q->elevator;
229 
230         if (e->type->ops.sq.elevator_deactivate_req_fn)
231                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
232 }
233 
234 int elv_register_queue(struct request_queue *q);
235 void elv_unregister_queue(struct request_queue *q);
236 
237 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
238 
239 #ifdef CONFIG_FAIL_IO_TIMEOUT
240 int blk_should_fake_timeout(struct request_queue *);
241 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
242 ssize_t part_timeout_store(struct device *, struct device_attribute *,
243                                 const char *, size_t);
244 #else
245 static inline int blk_should_fake_timeout(struct request_queue *q)
246 {
247         return 0;
248 }
249 #endif
250 
251 int ll_back_merge_fn(struct request_queue *q, struct request *req,
252                      struct bio *bio);
253 int ll_front_merge_fn(struct request_queue *q, struct request *req, 
254                       struct bio *bio);
255 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
256 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
257 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
258                                 struct request *next);
259 void blk_recalc_rq_segments(struct request *rq);
260 void blk_rq_set_mixed_merge(struct request *rq);
261 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
262 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
263 
264 void blk_queue_congestion_threshold(struct request_queue *q);
265 
266 int blk_dev_init(void);
267 
268 
269 /*
270  * Return the threshold (number of used requests) at which the queue is
271  * considered to be congested.  It include a little hysteresis to keep the
272  * context switch rate down.
273  */
274 static inline int queue_congestion_on_threshold(struct request_queue *q)
275 {
276         return q->nr_congestion_on;
277 }
278 
279 /*
280  * The threshold at which a queue is considered to be uncongested
281  */
282 static inline int queue_congestion_off_threshold(struct request_queue *q)
283 {
284         return q->nr_congestion_off;
285 }
286 
287 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
288 
289 /*
290  * Contribute to IO statistics IFF:
291  *
292  *      a) it's attached to a gendisk, and
293  *      b) the queue had IO stats enabled when this request was started, and
294  *      c) it's a file system request
295  */
296 static inline int blk_do_io_stat(struct request *rq)
297 {
298         return rq->rq_disk &&
299                (rq->rq_flags & RQF_IO_STAT) &&
300                 !blk_rq_is_passthrough(rq);
301 }
302 
303 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
304 {
305         req->cmd_flags |= REQ_NOMERGE;
306         if (req == q->last_merge)
307                 q->last_merge = NULL;
308 }
309 
310 /*
311  * Steal a bit from this field for legacy IO path atomic IO marking. Note that
312  * setting the deadline clears the bottom bit, potentially clearing the
313  * completed bit. The user has to be OK with this (current ones are fine).
314  */
315 static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
316 {
317         rq->__deadline = time & ~0x1UL;
318 }
319 
320 static inline unsigned long blk_rq_deadline(struct request *rq)
321 {
322         return rq->__deadline & ~0x1UL;
323 }
324 
325 /*
326  * Internal io_context interface
327  */
328 void get_io_context(struct io_context *ioc);
329 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
330 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
331                              gfp_t gfp_mask);
332 void ioc_clear_queue(struct request_queue *q);
333 
334 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
335 
336 /**
337  * rq_ioc - determine io_context for request allocation
338  * @bio: request being allocated is for this bio (can be %NULL)
339  *
340  * Determine io_context to use for request allocation for @bio.  May return
341  * %NULL if %current->io_context doesn't exist.
342  */
343 static inline struct io_context *rq_ioc(struct bio *bio)
344 {
345 #ifdef CONFIG_BLK_CGROUP
346         if (bio && bio->bi_ioc)
347                 return bio->bi_ioc;
348 #endif
349         return current->io_context;
350 }
351 
352 /**
353  * create_io_context - try to create task->io_context
354  * @gfp_mask: allocation mask
355  * @node: allocation node
356  *
357  * If %current->io_context is %NULL, allocate a new io_context and install
358  * it.  Returns the current %current->io_context which may be %NULL if
359  * allocation failed.
360  *
361  * Note that this function can't be called with IRQ disabled because
362  * task_lock which protects %current->io_context is IRQ-unsafe.
363  */
364 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
365 {
366         WARN_ON_ONCE(irqs_disabled());
367         if (unlikely(!current->io_context))
368                 create_task_io_context(current, gfp_mask, node);
369         return current->io_context;
370 }
371 
372 /*
373  * Internal throttling interface
374  */
375 #ifdef CONFIG_BLK_DEV_THROTTLING
376 extern void blk_throtl_drain(struct request_queue *q);
377 extern int blk_throtl_init(struct request_queue *q);
378 extern void blk_throtl_exit(struct request_queue *q);
379 extern void blk_throtl_register_queue(struct request_queue *q);
380 #else /* CONFIG_BLK_DEV_THROTTLING */
381 static inline void blk_throtl_drain(struct request_queue *q) { }
382 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
383 static inline void blk_throtl_exit(struct request_queue *q) { }
384 static inline void blk_throtl_register_queue(struct request_queue *q) { }
385 #endif /* CONFIG_BLK_DEV_THROTTLING */
386 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
387 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
388 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
389         const char *page, size_t count);
390 extern void blk_throtl_bio_endio(struct bio *bio);
391 extern void blk_throtl_stat_add(struct request *rq, u64 time);
392 #else
393 static inline void blk_throtl_bio_endio(struct bio *bio) { }
394 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
395 #endif
396 
397 #ifdef CONFIG_BOUNCE
398 extern int init_emergency_isa_pool(void);
399 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
400 #else
401 static inline int init_emergency_isa_pool(void)
402 {
403         return 0;
404 }
405 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
406 {
407 }
408 #endif /* CONFIG_BOUNCE */
409 
410 extern void blk_drain_queue(struct request_queue *q);
411 
412 #endif /* BLK_INTERNAL_H */
413 

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