xref: /linux-6.15/include/linux/blkdev.h (revision 6ea76f33)
1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
3 
4 #include <linux/sched.h>
5 
6 #ifdef CONFIG_BLOCK
7 
8 #include <linux/major.h>
9 #include <linux/genhd.h>
10 #include <linux/list.h>
11 #include <linux/llist.h>
12 #include <linux/timer.h>
13 #include <linux/workqueue.h>
14 #include <linux/pagemap.h>
15 #include <linux/backing-dev-defs.h>
16 #include <linux/wait.h>
17 #include <linux/mempool.h>
18 #include <linux/pfn.h>
19 #include <linux/bio.h>
20 #include <linux/stringify.h>
21 #include <linux/gfp.h>
22 #include <linux/bsg.h>
23 #include <linux/smp.h>
24 #include <linux/rcupdate.h>
25 #include <linux/percpu-refcount.h>
26 #include <linux/scatterlist.h>
27 #include <linux/blkzoned.h>
28 
29 struct module;
30 struct scsi_ioctl_command;
31 
32 struct request_queue;
33 struct elevator_queue;
34 struct blk_trace;
35 struct request;
36 struct sg_io_hdr;
37 struct bsg_job;
38 struct blkcg_gq;
39 struct blk_flush_queue;
40 struct pr_ops;
41 struct rq_wb;
42 
43 #define BLKDEV_MIN_RQ	4
44 #define BLKDEV_MAX_RQ	128	/* Default maximum */
45 
46 /*
47  * Maximum number of blkcg policies allowed to be registered concurrently.
48  * Defined here to simplify include dependency.
49  */
50 #define BLKCG_MAX_POLS		2
51 
52 typedef void (rq_end_io_fn)(struct request *, int);
53 
54 #define BLK_RL_SYNCFULL		(1U << 0)
55 #define BLK_RL_ASYNCFULL	(1U << 1)
56 
57 struct request_list {
58 	struct request_queue	*q;	/* the queue this rl belongs to */
59 #ifdef CONFIG_BLK_CGROUP
60 	struct blkcg_gq		*blkg;	/* blkg this request pool belongs to */
61 #endif
62 	/*
63 	 * count[], starved[], and wait[] are indexed by
64 	 * BLK_RW_SYNC/BLK_RW_ASYNC
65 	 */
66 	int			count[2];
67 	int			starved[2];
68 	mempool_t		*rq_pool;
69 	wait_queue_head_t	wait[2];
70 	unsigned int		flags;
71 };
72 
73 /*
74  * request command types
75  */
76 enum rq_cmd_type_bits {
77 	REQ_TYPE_FS		= 1,	/* fs request */
78 	REQ_TYPE_BLOCK_PC,		/* scsi command */
79 	REQ_TYPE_DRV_PRIV,		/* driver defined types from here */
80 };
81 
82 /*
83  * request flags */
84 typedef __u32 __bitwise req_flags_t;
85 
86 /* elevator knows about this request */
87 #define RQF_SORTED		((__force req_flags_t)(1 << 0))
88 /* drive already may have started this one */
89 #define RQF_STARTED		((__force req_flags_t)(1 << 1))
90 /* uses tagged queueing */
91 #define RQF_QUEUED		((__force req_flags_t)(1 << 2))
92 /* may not be passed by ioscheduler */
93 #define RQF_SOFTBARRIER		((__force req_flags_t)(1 << 3))
94 /* request for flush sequence */
95 #define RQF_FLUSH_SEQ		((__force req_flags_t)(1 << 4))
96 /* merge of different types, fail separately */
97 #define RQF_MIXED_MERGE		((__force req_flags_t)(1 << 5))
98 /* track inflight for MQ */
99 #define RQF_MQ_INFLIGHT		((__force req_flags_t)(1 << 6))
100 /* don't call prep for this one */
101 #define RQF_DONTPREP		((__force req_flags_t)(1 << 7))
102 /* set for "ide_preempt" requests and also for requests for which the SCSI
103    "quiesce" state must be ignored. */
104 #define RQF_PREEMPT		((__force req_flags_t)(1 << 8))
105 /* contains copies of user pages */
106 #define RQF_COPY_USER		((__force req_flags_t)(1 << 9))
107 /* vaguely specified driver internal error.  Ignored by the block layer */
108 #define RQF_FAILED		((__force req_flags_t)(1 << 10))
109 /* don't warn about errors */
110 #define RQF_QUIET		((__force req_flags_t)(1 << 11))
111 /* elevator private data attached */
112 #define RQF_ELVPRIV		((__force req_flags_t)(1 << 12))
113 /* account I/O stat */
114 #define RQF_IO_STAT		((__force req_flags_t)(1 << 13))
115 /* request came from our alloc pool */
116 #define RQF_ALLOCED		((__force req_flags_t)(1 << 14))
117 /* runtime pm request */
118 #define RQF_PM			((__force req_flags_t)(1 << 15))
119 /* on IO scheduler merge hash */
120 #define RQF_HASHED		((__force req_flags_t)(1 << 16))
121 /* IO stats tracking on */
122 #define RQF_STATS		((__force req_flags_t)(1 << 17))
123 
124 /* flags that prevent us from merging requests: */
125 #define RQF_NOMERGE_FLAGS \
126 	(RQF_STARTED | RQF_SOFTBARRIER | RQF_FLUSH_SEQ)
127 
128 #define BLK_MAX_CDB	16
129 
130 /*
131  * Try to put the fields that are referenced together in the same cacheline.
132  *
133  * If you modify this structure, make sure to update blk_rq_init() and
134  * especially blk_mq_rq_ctx_init() to take care of the added fields.
135  */
136 struct request {
137 	struct list_head queuelist;
138 	union {
139 		struct call_single_data csd;
140 		u64 fifo_time;
141 	};
142 
143 	struct request_queue *q;
144 	struct blk_mq_ctx *mq_ctx;
145 
146 	int cpu;
147 	unsigned cmd_type;
148 	unsigned int cmd_flags;		/* op and common flags */
149 	req_flags_t rq_flags;
150 	unsigned long atomic_flags;
151 
152 	/* the following two fields are internal, NEVER access directly */
153 	unsigned int __data_len;	/* total data len */
154 	sector_t __sector;		/* sector cursor */
155 
156 	struct bio *bio;
157 	struct bio *biotail;
158 
159 	/*
160 	 * The hash is used inside the scheduler, and killed once the
161 	 * request reaches the dispatch list. The ipi_list is only used
162 	 * to queue the request for softirq completion, which is long
163 	 * after the request has been unhashed (and even removed from
164 	 * the dispatch list).
165 	 */
166 	union {
167 		struct hlist_node hash;	/* merge hash */
168 		struct list_head ipi_list;
169 	};
170 
171 	/*
172 	 * The rb_node is only used inside the io scheduler, requests
173 	 * are pruned when moved to the dispatch queue. So let the
174 	 * completion_data share space with the rb_node.
175 	 */
176 	union {
177 		struct rb_node rb_node;	/* sort/lookup */
178 		void *completion_data;
179 	};
180 
181 	/*
182 	 * Three pointers are available for the IO schedulers, if they need
183 	 * more they have to dynamically allocate it.  Flush requests are
184 	 * never put on the IO scheduler. So let the flush fields share
185 	 * space with the elevator data.
186 	 */
187 	union {
188 		struct {
189 			struct io_cq		*icq;
190 			void			*priv[2];
191 		} elv;
192 
193 		struct {
194 			unsigned int		seq;
195 			struct list_head	list;
196 			rq_end_io_fn		*saved_end_io;
197 		} flush;
198 	};
199 
200 	struct gendisk *rq_disk;
201 	struct hd_struct *part;
202 	unsigned long start_time;
203 	struct blk_issue_stat issue_stat;
204 #ifdef CONFIG_BLK_CGROUP
205 	struct request_list *rl;		/* rl this rq is alloced from */
206 	unsigned long long start_time_ns;
207 	unsigned long long io_start_time_ns;    /* when passed to hardware */
208 #endif
209 	/* Number of scatter-gather DMA addr+len pairs after
210 	 * physical address coalescing is performed.
211 	 */
212 	unsigned short nr_phys_segments;
213 #if defined(CONFIG_BLK_DEV_INTEGRITY)
214 	unsigned short nr_integrity_segments;
215 #endif
216 
217 	unsigned short ioprio;
218 
219 	void *special;		/* opaque pointer available for LLD use */
220 
221 	int tag;
222 	int errors;
223 
224 	/*
225 	 * when request is used as a packet command carrier
226 	 */
227 	unsigned char __cmd[BLK_MAX_CDB];
228 	unsigned char *cmd;
229 	unsigned short cmd_len;
230 
231 	unsigned int extra_len;	/* length of alignment and padding */
232 	unsigned int sense_len;
233 	unsigned int resid_len;	/* residual count */
234 	void *sense;
235 
236 	unsigned long deadline;
237 	struct list_head timeout_list;
238 	unsigned int timeout;
239 	int retries;
240 
241 	/*
242 	 * completion callback.
243 	 */
244 	rq_end_io_fn *end_io;
245 	void *end_io_data;
246 
247 	/* for bidi */
248 	struct request *next_rq;
249 };
250 
251 static inline unsigned short req_get_ioprio(struct request *req)
252 {
253 	return req->ioprio;
254 }
255 
256 #include <linux/elevator.h>
257 
258 struct blk_queue_ctx;
259 
260 typedef void (request_fn_proc) (struct request_queue *q);
261 typedef blk_qc_t (make_request_fn) (struct request_queue *q, struct bio *bio);
262 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
263 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
264 
265 struct bio_vec;
266 typedef void (softirq_done_fn)(struct request *);
267 typedef int (dma_drain_needed_fn)(struct request *);
268 typedef int (lld_busy_fn) (struct request_queue *q);
269 typedef int (bsg_job_fn) (struct bsg_job *);
270 
271 enum blk_eh_timer_return {
272 	BLK_EH_NOT_HANDLED,
273 	BLK_EH_HANDLED,
274 	BLK_EH_RESET_TIMER,
275 };
276 
277 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
278 
279 enum blk_queue_state {
280 	Queue_down,
281 	Queue_up,
282 };
283 
284 struct blk_queue_tag {
285 	struct request **tag_index;	/* map of busy tags */
286 	unsigned long *tag_map;		/* bit map of free/busy tags */
287 	int busy;			/* current depth */
288 	int max_depth;			/* what we will send to device */
289 	int real_max_depth;		/* what the array can hold */
290 	atomic_t refcnt;		/* map can be shared */
291 	int alloc_policy;		/* tag allocation policy */
292 	int next_tag;			/* next tag */
293 };
294 #define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */
295 #define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */
296 
297 #define BLK_SCSI_MAX_CMDS	(256)
298 #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
299 
300 /*
301  * Zoned block device models (zoned limit).
302  */
303 enum blk_zoned_model {
304 	BLK_ZONED_NONE,	/* Regular block device */
305 	BLK_ZONED_HA,	/* Host-aware zoned block device */
306 	BLK_ZONED_HM,	/* Host-managed zoned block device */
307 };
308 
309 struct queue_limits {
310 	unsigned long		bounce_pfn;
311 	unsigned long		seg_boundary_mask;
312 	unsigned long		virt_boundary_mask;
313 
314 	unsigned int		max_hw_sectors;
315 	unsigned int		max_dev_sectors;
316 	unsigned int		chunk_sectors;
317 	unsigned int		max_sectors;
318 	unsigned int		max_segment_size;
319 	unsigned int		physical_block_size;
320 	unsigned int		alignment_offset;
321 	unsigned int		io_min;
322 	unsigned int		io_opt;
323 	unsigned int		max_discard_sectors;
324 	unsigned int		max_hw_discard_sectors;
325 	unsigned int		max_write_same_sectors;
326 	unsigned int		max_write_zeroes_sectors;
327 	unsigned int		discard_granularity;
328 	unsigned int		discard_alignment;
329 
330 	unsigned short		logical_block_size;
331 	unsigned short		max_segments;
332 	unsigned short		max_integrity_segments;
333 
334 	unsigned char		misaligned;
335 	unsigned char		discard_misaligned;
336 	unsigned char		cluster;
337 	unsigned char		discard_zeroes_data;
338 	unsigned char		raid_partial_stripes_expensive;
339 	enum blk_zoned_model	zoned;
340 };
341 
342 #ifdef CONFIG_BLK_DEV_ZONED
343 
344 struct blk_zone_report_hdr {
345 	unsigned int	nr_zones;
346 	u8		padding[60];
347 };
348 
349 extern int blkdev_report_zones(struct block_device *bdev,
350 			       sector_t sector, struct blk_zone *zones,
351 			       unsigned int *nr_zones, gfp_t gfp_mask);
352 extern int blkdev_reset_zones(struct block_device *bdev, sector_t sectors,
353 			      sector_t nr_sectors, gfp_t gfp_mask);
354 
355 extern int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
356 				     unsigned int cmd, unsigned long arg);
357 extern int blkdev_reset_zones_ioctl(struct block_device *bdev, fmode_t mode,
358 				    unsigned int cmd, unsigned long arg);
359 
360 #else /* CONFIG_BLK_DEV_ZONED */
361 
362 static inline int blkdev_report_zones_ioctl(struct block_device *bdev,
363 					    fmode_t mode, unsigned int cmd,
364 					    unsigned long arg)
365 {
366 	return -ENOTTY;
367 }
368 
369 static inline int blkdev_reset_zones_ioctl(struct block_device *bdev,
370 					   fmode_t mode, unsigned int cmd,
371 					   unsigned long arg)
372 {
373 	return -ENOTTY;
374 }
375 
376 #endif /* CONFIG_BLK_DEV_ZONED */
377 
378 struct request_queue {
379 	/*
380 	 * Together with queue_head for cacheline sharing
381 	 */
382 	struct list_head	queue_head;
383 	struct request		*last_merge;
384 	struct elevator_queue	*elevator;
385 	int			nr_rqs[2];	/* # allocated [a]sync rqs */
386 	int			nr_rqs_elvpriv;	/* # allocated rqs w/ elvpriv */
387 
388 	struct rq_wb		*rq_wb;
389 
390 	/*
391 	 * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
392 	 * is used, root blkg allocates from @q->root_rl and all other
393 	 * blkgs from their own blkg->rl.  Which one to use should be
394 	 * determined using bio_request_list().
395 	 */
396 	struct request_list	root_rl;
397 
398 	request_fn_proc		*request_fn;
399 	make_request_fn		*make_request_fn;
400 	prep_rq_fn		*prep_rq_fn;
401 	unprep_rq_fn		*unprep_rq_fn;
402 	softirq_done_fn		*softirq_done_fn;
403 	rq_timed_out_fn		*rq_timed_out_fn;
404 	dma_drain_needed_fn	*dma_drain_needed;
405 	lld_busy_fn		*lld_busy_fn;
406 
407 	struct blk_mq_ops	*mq_ops;
408 
409 	unsigned int		*mq_map;
410 
411 	/* sw queues */
412 	struct blk_mq_ctx __percpu	*queue_ctx;
413 	unsigned int		nr_queues;
414 
415 	unsigned int		queue_depth;
416 
417 	/* hw dispatch queues */
418 	struct blk_mq_hw_ctx	**queue_hw_ctx;
419 	unsigned int		nr_hw_queues;
420 
421 	/*
422 	 * Dispatch queue sorting
423 	 */
424 	sector_t		end_sector;
425 	struct request		*boundary_rq;
426 
427 	/*
428 	 * Delayed queue handling
429 	 */
430 	struct delayed_work	delay_work;
431 
432 	struct backing_dev_info	backing_dev_info;
433 
434 	/*
435 	 * The queue owner gets to use this for whatever they like.
436 	 * ll_rw_blk doesn't touch it.
437 	 */
438 	void			*queuedata;
439 
440 	/*
441 	 * various queue flags, see QUEUE_* below
442 	 */
443 	unsigned long		queue_flags;
444 
445 	/*
446 	 * ida allocated id for this queue.  Used to index queues from
447 	 * ioctx.
448 	 */
449 	int			id;
450 
451 	/*
452 	 * queue needs bounce pages for pages above this limit
453 	 */
454 	gfp_t			bounce_gfp;
455 
456 	/*
457 	 * protects queue structures from reentrancy. ->__queue_lock should
458 	 * _never_ be used directly, it is queue private. always use
459 	 * ->queue_lock.
460 	 */
461 	spinlock_t		__queue_lock;
462 	spinlock_t		*queue_lock;
463 
464 	/*
465 	 * queue kobject
466 	 */
467 	struct kobject kobj;
468 
469 	/*
470 	 * mq queue kobject
471 	 */
472 	struct kobject mq_kobj;
473 
474 #ifdef  CONFIG_BLK_DEV_INTEGRITY
475 	struct blk_integrity integrity;
476 #endif	/* CONFIG_BLK_DEV_INTEGRITY */
477 
478 #ifdef CONFIG_PM
479 	struct device		*dev;
480 	int			rpm_status;
481 	unsigned int		nr_pending;
482 #endif
483 
484 	/*
485 	 * queue settings
486 	 */
487 	unsigned long		nr_requests;	/* Max # of requests */
488 	unsigned int		nr_congestion_on;
489 	unsigned int		nr_congestion_off;
490 	unsigned int		nr_batching;
491 
492 	unsigned int		dma_drain_size;
493 	void			*dma_drain_buffer;
494 	unsigned int		dma_pad_mask;
495 	unsigned int		dma_alignment;
496 
497 	struct blk_queue_tag	*queue_tags;
498 	struct list_head	tag_busy_list;
499 
500 	unsigned int		nr_sorted;
501 	unsigned int		in_flight[2];
502 
503 	struct blk_rq_stat	rq_stats[2];
504 
505 	/*
506 	 * Number of active block driver functions for which blk_drain_queue()
507 	 * must wait. Must be incremented around functions that unlock the
508 	 * queue_lock internally, e.g. scsi_request_fn().
509 	 */
510 	unsigned int		request_fn_active;
511 
512 	unsigned int		rq_timeout;
513 	int			poll_nsec;
514 	struct timer_list	timeout;
515 	struct work_struct	timeout_work;
516 	struct list_head	timeout_list;
517 
518 	struct list_head	icq_list;
519 #ifdef CONFIG_BLK_CGROUP
520 	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
521 	struct blkcg_gq		*root_blkg;
522 	struct list_head	blkg_list;
523 #endif
524 
525 	struct queue_limits	limits;
526 
527 	/*
528 	 * sg stuff
529 	 */
530 	unsigned int		sg_timeout;
531 	unsigned int		sg_reserved_size;
532 	int			node;
533 #ifdef CONFIG_BLK_DEV_IO_TRACE
534 	struct blk_trace	*blk_trace;
535 #endif
536 	/*
537 	 * for flush operations
538 	 */
539 	struct blk_flush_queue	*fq;
540 
541 	struct list_head	requeue_list;
542 	spinlock_t		requeue_lock;
543 	struct delayed_work	requeue_work;
544 
545 	struct mutex		sysfs_lock;
546 
547 	int			bypass_depth;
548 	atomic_t		mq_freeze_depth;
549 
550 #if defined(CONFIG_BLK_DEV_BSG)
551 	bsg_job_fn		*bsg_job_fn;
552 	int			bsg_job_size;
553 	struct bsg_class_device bsg_dev;
554 #endif
555 
556 #ifdef CONFIG_BLK_DEV_THROTTLING
557 	/* Throttle data */
558 	struct throtl_data *td;
559 #endif
560 	struct rcu_head		rcu_head;
561 	wait_queue_head_t	mq_freeze_wq;
562 	struct percpu_ref	q_usage_counter;
563 	struct list_head	all_q_node;
564 
565 	struct blk_mq_tag_set	*tag_set;
566 	struct list_head	tag_set_list;
567 	struct bio_set		*bio_split;
568 
569 	bool			mq_sysfs_init_done;
570 };
571 
572 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
573 #define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
574 #define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
575 #define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
576 #define QUEUE_FLAG_DYING	5	/* queue being torn down */
577 #define QUEUE_FLAG_BYPASS	6	/* act as dumb FIFO queue */
578 #define QUEUE_FLAG_BIDI		7	/* queue supports bidi requests */
579 #define QUEUE_FLAG_NOMERGES     8	/* disable merge attempts */
580 #define QUEUE_FLAG_SAME_COMP	9	/* complete on same CPU-group */
581 #define QUEUE_FLAG_FAIL_IO     10	/* fake timeout */
582 #define QUEUE_FLAG_STACKABLE   11	/* supports request stacking */
583 #define QUEUE_FLAG_NONROT      12	/* non-rotational device (SSD) */
584 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
585 #define QUEUE_FLAG_IO_STAT     13	/* do IO stats */
586 #define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
587 #define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
588 #define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
589 #define QUEUE_FLAG_SECERASE    17	/* supports secure erase */
590 #define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
591 #define QUEUE_FLAG_DEAD        19	/* queue tear-down finished */
592 #define QUEUE_FLAG_INIT_DONE   20	/* queue is initialized */
593 #define QUEUE_FLAG_NO_SG_MERGE 21	/* don't attempt to merge SG segments*/
594 #define QUEUE_FLAG_POLL	       22	/* IO polling enabled if set */
595 #define QUEUE_FLAG_WC	       23	/* Write back caching */
596 #define QUEUE_FLAG_FUA	       24	/* device supports FUA writes */
597 #define QUEUE_FLAG_FLUSH_NQ    25	/* flush not queueuable */
598 #define QUEUE_FLAG_DAX         26	/* device supports DAX */
599 #define QUEUE_FLAG_STATS       27	/* track rq completion times */
600 
601 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
602 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
603 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
604 				 (1 << QUEUE_FLAG_ADD_RANDOM))
605 
606 #define QUEUE_FLAG_MQ_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
607 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
608 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
609 				 (1 << QUEUE_FLAG_POLL))
610 
611 static inline void queue_lockdep_assert_held(struct request_queue *q)
612 {
613 	if (q->queue_lock)
614 		lockdep_assert_held(q->queue_lock);
615 }
616 
617 static inline void queue_flag_set_unlocked(unsigned int flag,
618 					   struct request_queue *q)
619 {
620 	__set_bit(flag, &q->queue_flags);
621 }
622 
623 static inline int queue_flag_test_and_clear(unsigned int flag,
624 					    struct request_queue *q)
625 {
626 	queue_lockdep_assert_held(q);
627 
628 	if (test_bit(flag, &q->queue_flags)) {
629 		__clear_bit(flag, &q->queue_flags);
630 		return 1;
631 	}
632 
633 	return 0;
634 }
635 
636 static inline int queue_flag_test_and_set(unsigned int flag,
637 					  struct request_queue *q)
638 {
639 	queue_lockdep_assert_held(q);
640 
641 	if (!test_bit(flag, &q->queue_flags)) {
642 		__set_bit(flag, &q->queue_flags);
643 		return 0;
644 	}
645 
646 	return 1;
647 }
648 
649 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
650 {
651 	queue_lockdep_assert_held(q);
652 	__set_bit(flag, &q->queue_flags);
653 }
654 
655 static inline void queue_flag_clear_unlocked(unsigned int flag,
656 					     struct request_queue *q)
657 {
658 	__clear_bit(flag, &q->queue_flags);
659 }
660 
661 static inline int queue_in_flight(struct request_queue *q)
662 {
663 	return q->in_flight[0] + q->in_flight[1];
664 }
665 
666 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
667 {
668 	queue_lockdep_assert_held(q);
669 	__clear_bit(flag, &q->queue_flags);
670 }
671 
672 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
673 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
674 #define blk_queue_dying(q)	test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
675 #define blk_queue_dead(q)	test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
676 #define blk_queue_bypass(q)	test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
677 #define blk_queue_init_done(q)	test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
678 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
679 #define blk_queue_noxmerges(q)	\
680 	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
681 #define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
682 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
683 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
684 #define blk_queue_stackable(q)	\
685 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
686 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
687 #define blk_queue_secure_erase(q) \
688 	(test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags))
689 #define blk_queue_dax(q)	test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
690 
691 #define blk_noretry_request(rq) \
692 	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
693 			     REQ_FAILFAST_DRIVER))
694 
695 #define blk_account_rq(rq) \
696 	(((rq)->rq_flags & RQF_STARTED) && \
697 	 ((rq)->cmd_type == REQ_TYPE_FS))
698 
699 #define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
700 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
701 /* rq->queuelist of dequeued request must be list_empty() */
702 #define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
703 
704 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
705 
706 #define rq_data_dir(rq)		(op_is_write(req_op(rq)) ? WRITE : READ)
707 
708 /*
709  * Driver can handle struct request, if it either has an old style
710  * request_fn defined, or is blk-mq based.
711  */
712 static inline bool queue_is_rq_based(struct request_queue *q)
713 {
714 	return q->request_fn || q->mq_ops;
715 }
716 
717 static inline unsigned int blk_queue_cluster(struct request_queue *q)
718 {
719 	return q->limits.cluster;
720 }
721 
722 static inline enum blk_zoned_model
723 blk_queue_zoned_model(struct request_queue *q)
724 {
725 	return q->limits.zoned;
726 }
727 
728 static inline bool blk_queue_is_zoned(struct request_queue *q)
729 {
730 	switch (blk_queue_zoned_model(q)) {
731 	case BLK_ZONED_HA:
732 	case BLK_ZONED_HM:
733 		return true;
734 	default:
735 		return false;
736 	}
737 }
738 
739 static inline unsigned int blk_queue_zone_size(struct request_queue *q)
740 {
741 	return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0;
742 }
743 
744 static inline bool rq_is_sync(struct request *rq)
745 {
746 	return op_is_sync(rq->cmd_flags);
747 }
748 
749 static inline bool blk_rl_full(struct request_list *rl, bool sync)
750 {
751 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
752 
753 	return rl->flags & flag;
754 }
755 
756 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
757 {
758 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
759 
760 	rl->flags |= flag;
761 }
762 
763 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
764 {
765 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
766 
767 	rl->flags &= ~flag;
768 }
769 
770 static inline bool rq_mergeable(struct request *rq)
771 {
772 	if (rq->cmd_type != REQ_TYPE_FS)
773 		return false;
774 
775 	if (req_op(rq) == REQ_OP_FLUSH)
776 		return false;
777 
778 	if (req_op(rq) == REQ_OP_WRITE_ZEROES)
779 		return false;
780 
781 	if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
782 		return false;
783 	if (rq->rq_flags & RQF_NOMERGE_FLAGS)
784 		return false;
785 
786 	return true;
787 }
788 
789 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
790 {
791 	if (bio_data(a) == bio_data(b))
792 		return true;
793 
794 	return false;
795 }
796 
797 static inline unsigned int blk_queue_depth(struct request_queue *q)
798 {
799 	if (q->queue_depth)
800 		return q->queue_depth;
801 
802 	return q->nr_requests;
803 }
804 
805 /*
806  * q->prep_rq_fn return values
807  */
808 enum {
809 	BLKPREP_OK,		/* serve it */
810 	BLKPREP_KILL,		/* fatal error, kill, return -EIO */
811 	BLKPREP_DEFER,		/* leave on queue */
812 	BLKPREP_INVALID,	/* invalid command, kill, return -EREMOTEIO */
813 };
814 
815 extern unsigned long blk_max_low_pfn, blk_max_pfn;
816 
817 /*
818  * standard bounce addresses:
819  *
820  * BLK_BOUNCE_HIGH	: bounce all highmem pages
821  * BLK_BOUNCE_ANY	: don't bounce anything
822  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
823  */
824 
825 #if BITS_PER_LONG == 32
826 #define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
827 #else
828 #define BLK_BOUNCE_HIGH		-1ULL
829 #endif
830 #define BLK_BOUNCE_ANY		(-1ULL)
831 #define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
832 
833 /*
834  * default timeout for SG_IO if none specified
835  */
836 #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
837 #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
838 
839 #ifdef CONFIG_BOUNCE
840 extern int init_emergency_isa_pool(void);
841 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
842 #else
843 static inline int init_emergency_isa_pool(void)
844 {
845 	return 0;
846 }
847 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
848 {
849 }
850 #endif /* CONFIG_MMU */
851 
852 struct rq_map_data {
853 	struct page **pages;
854 	int page_order;
855 	int nr_entries;
856 	unsigned long offset;
857 	int null_mapped;
858 	int from_user;
859 };
860 
861 struct req_iterator {
862 	struct bvec_iter iter;
863 	struct bio *bio;
864 };
865 
866 /* This should not be used directly - use rq_for_each_segment */
867 #define for_each_bio(_bio)		\
868 	for (; _bio; _bio = _bio->bi_next)
869 #define __rq_for_each_bio(_bio, rq)	\
870 	if ((rq->bio))			\
871 		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
872 
873 #define rq_for_each_segment(bvl, _rq, _iter)			\
874 	__rq_for_each_bio(_iter.bio, _rq)			\
875 		bio_for_each_segment(bvl, _iter.bio, _iter.iter)
876 
877 #define rq_iter_last(bvec, _iter)				\
878 		(_iter.bio->bi_next == NULL &&			\
879 		 bio_iter_last(bvec, _iter.iter))
880 
881 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
882 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
883 #endif
884 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
885 extern void rq_flush_dcache_pages(struct request *rq);
886 #else
887 static inline void rq_flush_dcache_pages(struct request *rq)
888 {
889 }
890 #endif
891 
892 #ifdef CONFIG_PRINTK
893 #define vfs_msg(sb, level, fmt, ...)				\
894 	__vfs_msg(sb, level, fmt, ##__VA_ARGS__)
895 #else
896 #define vfs_msg(sb, level, fmt, ...)				\
897 do {								\
898 	no_printk(fmt, ##__VA_ARGS__);				\
899 	__vfs_msg(sb, "", " ");					\
900 } while (0)
901 #endif
902 
903 extern int blk_register_queue(struct gendisk *disk);
904 extern void blk_unregister_queue(struct gendisk *disk);
905 extern blk_qc_t generic_make_request(struct bio *bio);
906 extern void blk_rq_init(struct request_queue *q, struct request *rq);
907 extern void blk_put_request(struct request *);
908 extern void __blk_put_request(struct request_queue *, struct request *);
909 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
910 extern void blk_rq_set_block_pc(struct request *);
911 extern void blk_requeue_request(struct request_queue *, struct request *);
912 extern void blk_add_request_payload(struct request *rq, struct page *page,
913 		int offset, unsigned int len);
914 extern int blk_lld_busy(struct request_queue *q);
915 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
916 			     struct bio_set *bs, gfp_t gfp_mask,
917 			     int (*bio_ctr)(struct bio *, struct bio *, void *),
918 			     void *data);
919 extern void blk_rq_unprep_clone(struct request *rq);
920 extern int blk_insert_cloned_request(struct request_queue *q,
921 				     struct request *rq);
922 extern int blk_rq_append_bio(struct request *rq, struct bio *bio);
923 extern void blk_delay_queue(struct request_queue *, unsigned long);
924 extern void blk_queue_split(struct request_queue *, struct bio **,
925 			    struct bio_set *);
926 extern void blk_recount_segments(struct request_queue *, struct bio *);
927 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
928 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
929 			      unsigned int, void __user *);
930 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
931 			  unsigned int, void __user *);
932 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
933 			 struct scsi_ioctl_command __user *);
934 
935 extern int blk_queue_enter(struct request_queue *q, bool nowait);
936 extern void blk_queue_exit(struct request_queue *q);
937 extern void blk_start_queue(struct request_queue *q);
938 extern void blk_start_queue_async(struct request_queue *q);
939 extern void blk_stop_queue(struct request_queue *q);
940 extern void blk_sync_queue(struct request_queue *q);
941 extern void __blk_stop_queue(struct request_queue *q);
942 extern void __blk_run_queue(struct request_queue *q);
943 extern void __blk_run_queue_uncond(struct request_queue *q);
944 extern void blk_run_queue(struct request_queue *);
945 extern void blk_run_queue_async(struct request_queue *q);
946 extern void blk_mq_quiesce_queue(struct request_queue *q);
947 extern int blk_rq_map_user(struct request_queue *, struct request *,
948 			   struct rq_map_data *, void __user *, unsigned long,
949 			   gfp_t);
950 extern int blk_rq_unmap_user(struct bio *);
951 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
952 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
953 			       struct rq_map_data *, const struct iov_iter *,
954 			       gfp_t);
955 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
956 			  struct request *, int);
957 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
958 				  struct request *, int, rq_end_io_fn *);
959 
960 bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
961 
962 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
963 {
964 	return bdev->bd_disk->queue;	/* this is never NULL */
965 }
966 
967 /*
968  * blk_rq_pos()			: the current sector
969  * blk_rq_bytes()		: bytes left in the entire request
970  * blk_rq_cur_bytes()		: bytes left in the current segment
971  * blk_rq_err_bytes()		: bytes left till the next error boundary
972  * blk_rq_sectors()		: sectors left in the entire request
973  * blk_rq_cur_sectors()		: sectors left in the current segment
974  */
975 static inline sector_t blk_rq_pos(const struct request *rq)
976 {
977 	return rq->__sector;
978 }
979 
980 static inline unsigned int blk_rq_bytes(const struct request *rq)
981 {
982 	return rq->__data_len;
983 }
984 
985 static inline int blk_rq_cur_bytes(const struct request *rq)
986 {
987 	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
988 }
989 
990 extern unsigned int blk_rq_err_bytes(const struct request *rq);
991 
992 static inline unsigned int blk_rq_sectors(const struct request *rq)
993 {
994 	return blk_rq_bytes(rq) >> 9;
995 }
996 
997 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
998 {
999 	return blk_rq_cur_bytes(rq) >> 9;
1000 }
1001 
1002 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
1003 						     int op)
1004 {
1005 	if (unlikely(op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE))
1006 		return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
1007 
1008 	if (unlikely(op == REQ_OP_WRITE_SAME))
1009 		return q->limits.max_write_same_sectors;
1010 
1011 	if (unlikely(op == REQ_OP_WRITE_ZEROES))
1012 		return q->limits.max_write_zeroes_sectors;
1013 
1014 	return q->limits.max_sectors;
1015 }
1016 
1017 /*
1018  * Return maximum size of a request at given offset. Only valid for
1019  * file system requests.
1020  */
1021 static inline unsigned int blk_max_size_offset(struct request_queue *q,
1022 					       sector_t offset)
1023 {
1024 	if (!q->limits.chunk_sectors)
1025 		return q->limits.max_sectors;
1026 
1027 	return q->limits.chunk_sectors -
1028 			(offset & (q->limits.chunk_sectors - 1));
1029 }
1030 
1031 static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
1032 						  sector_t offset)
1033 {
1034 	struct request_queue *q = rq->q;
1035 
1036 	if (unlikely(rq->cmd_type != REQ_TYPE_FS))
1037 		return q->limits.max_hw_sectors;
1038 
1039 	if (!q->limits.chunk_sectors ||
1040 	    req_op(rq) == REQ_OP_DISCARD ||
1041 	    req_op(rq) == REQ_OP_SECURE_ERASE)
1042 		return blk_queue_get_max_sectors(q, req_op(rq));
1043 
1044 	return min(blk_max_size_offset(q, offset),
1045 			blk_queue_get_max_sectors(q, req_op(rq)));
1046 }
1047 
1048 static inline unsigned int blk_rq_count_bios(struct request *rq)
1049 {
1050 	unsigned int nr_bios = 0;
1051 	struct bio *bio;
1052 
1053 	__rq_for_each_bio(bio, rq)
1054 		nr_bios++;
1055 
1056 	return nr_bios;
1057 }
1058 
1059 /*
1060  * Request issue related functions.
1061  */
1062 extern struct request *blk_peek_request(struct request_queue *q);
1063 extern void blk_start_request(struct request *rq);
1064 extern struct request *blk_fetch_request(struct request_queue *q);
1065 
1066 /*
1067  * Request completion related functions.
1068  *
1069  * blk_update_request() completes given number of bytes and updates
1070  * the request without completing it.
1071  *
1072  * blk_end_request() and friends.  __blk_end_request() must be called
1073  * with the request queue spinlock acquired.
1074  *
1075  * Several drivers define their own end_request and call
1076  * blk_end_request() for parts of the original function.
1077  * This prevents code duplication in drivers.
1078  */
1079 extern bool blk_update_request(struct request *rq, int error,
1080 			       unsigned int nr_bytes);
1081 extern void blk_finish_request(struct request *rq, int error);
1082 extern bool blk_end_request(struct request *rq, int error,
1083 			    unsigned int nr_bytes);
1084 extern void blk_end_request_all(struct request *rq, int error);
1085 extern bool blk_end_request_cur(struct request *rq, int error);
1086 extern bool blk_end_request_err(struct request *rq, int error);
1087 extern bool __blk_end_request(struct request *rq, int error,
1088 			      unsigned int nr_bytes);
1089 extern void __blk_end_request_all(struct request *rq, int error);
1090 extern bool __blk_end_request_cur(struct request *rq, int error);
1091 extern bool __blk_end_request_err(struct request *rq, int error);
1092 
1093 extern void blk_complete_request(struct request *);
1094 extern void __blk_complete_request(struct request *);
1095 extern void blk_abort_request(struct request *);
1096 extern void blk_unprep_request(struct request *);
1097 
1098 /*
1099  * Access functions for manipulating queue properties
1100  */
1101 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
1102 					spinlock_t *lock, int node_id);
1103 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
1104 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
1105 						      request_fn_proc *, spinlock_t *);
1106 extern void blk_cleanup_queue(struct request_queue *);
1107 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
1108 extern void blk_queue_bounce_limit(struct request_queue *, u64);
1109 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
1110 extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
1111 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
1112 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
1113 extern void blk_queue_max_discard_sectors(struct request_queue *q,
1114 		unsigned int max_discard_sectors);
1115 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
1116 		unsigned int max_write_same_sectors);
1117 extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
1118 		unsigned int max_write_same_sectors);
1119 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
1120 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
1121 extern void blk_queue_alignment_offset(struct request_queue *q,
1122 				       unsigned int alignment);
1123 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
1124 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
1125 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
1126 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
1127 extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth);
1128 extern void blk_set_default_limits(struct queue_limits *lim);
1129 extern void blk_set_stacking_limits(struct queue_limits *lim);
1130 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
1131 			    sector_t offset);
1132 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
1133 			    sector_t offset);
1134 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
1135 			      sector_t offset);
1136 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
1137 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
1138 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
1139 extern int blk_queue_dma_drain(struct request_queue *q,
1140 			       dma_drain_needed_fn *dma_drain_needed,
1141 			       void *buf, unsigned int size);
1142 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
1143 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
1144 extern void blk_queue_virt_boundary(struct request_queue *, unsigned long);
1145 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
1146 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
1147 extern void blk_queue_dma_alignment(struct request_queue *, int);
1148 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
1149 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
1150 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
1151 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
1152 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
1153 extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fua);
1154 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
1155 
1156 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
1157 extern void blk_dump_rq_flags(struct request *, char *);
1158 extern long nr_blockdev_pages(void);
1159 
1160 bool __must_check blk_get_queue(struct request_queue *);
1161 struct request_queue *blk_alloc_queue(gfp_t);
1162 struct request_queue *blk_alloc_queue_node(gfp_t, int);
1163 extern void blk_put_queue(struct request_queue *);
1164 extern void blk_set_queue_dying(struct request_queue *);
1165 
1166 /*
1167  * block layer runtime pm functions
1168  */
1169 #ifdef CONFIG_PM
1170 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
1171 extern int blk_pre_runtime_suspend(struct request_queue *q);
1172 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
1173 extern void blk_pre_runtime_resume(struct request_queue *q);
1174 extern void blk_post_runtime_resume(struct request_queue *q, int err);
1175 extern void blk_set_runtime_active(struct request_queue *q);
1176 #else
1177 static inline void blk_pm_runtime_init(struct request_queue *q,
1178 	struct device *dev) {}
1179 static inline int blk_pre_runtime_suspend(struct request_queue *q)
1180 {
1181 	return -ENOSYS;
1182 }
1183 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
1184 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
1185 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1186 static inline void blk_set_runtime_active(struct request_queue *q) {}
1187 #endif
1188 
1189 /*
1190  * blk_plug permits building a queue of related requests by holding the I/O
1191  * fragments for a short period. This allows merging of sequential requests
1192  * into single larger request. As the requests are moved from a per-task list to
1193  * the device's request_queue in a batch, this results in improved scalability
1194  * as the lock contention for request_queue lock is reduced.
1195  *
1196  * It is ok not to disable preemption when adding the request to the plug list
1197  * or when attempting a merge, because blk_schedule_flush_list() will only flush
1198  * the plug list when the task sleeps by itself. For details, please see
1199  * schedule() where blk_schedule_flush_plug() is called.
1200  */
1201 struct blk_plug {
1202 	struct list_head list; /* requests */
1203 	struct list_head mq_list; /* blk-mq requests */
1204 	struct list_head cb_list; /* md requires an unplug callback */
1205 };
1206 #define BLK_MAX_REQUEST_COUNT 16
1207 #define BLK_PLUG_FLUSH_SIZE (128 * 1024)
1208 
1209 struct blk_plug_cb;
1210 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1211 struct blk_plug_cb {
1212 	struct list_head list;
1213 	blk_plug_cb_fn callback;
1214 	void *data;
1215 };
1216 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1217 					     void *data, int size);
1218 extern void blk_start_plug(struct blk_plug *);
1219 extern void blk_finish_plug(struct blk_plug *);
1220 extern void blk_flush_plug_list(struct blk_plug *, bool);
1221 
1222 static inline void blk_flush_plug(struct task_struct *tsk)
1223 {
1224 	struct blk_plug *plug = tsk->plug;
1225 
1226 	if (plug)
1227 		blk_flush_plug_list(plug, false);
1228 }
1229 
1230 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1231 {
1232 	struct blk_plug *plug = tsk->plug;
1233 
1234 	if (plug)
1235 		blk_flush_plug_list(plug, true);
1236 }
1237 
1238 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1239 {
1240 	struct blk_plug *plug = tsk->plug;
1241 
1242 	return plug &&
1243 		(!list_empty(&plug->list) ||
1244 		 !list_empty(&plug->mq_list) ||
1245 		 !list_empty(&plug->cb_list));
1246 }
1247 
1248 /*
1249  * tag stuff
1250  */
1251 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1252 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1253 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1254 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
1255 extern void blk_queue_free_tags(struct request_queue *);
1256 extern int blk_queue_resize_tags(struct request_queue *, int);
1257 extern void blk_queue_invalidate_tags(struct request_queue *);
1258 extern struct blk_queue_tag *blk_init_tags(int, int);
1259 extern void blk_free_tags(struct blk_queue_tag *);
1260 
1261 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1262 						int tag)
1263 {
1264 	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1265 		return NULL;
1266 	return bqt->tag_index[tag];
1267 }
1268 
1269 
1270 #define BLKDEV_DISCARD_SECURE	(1 << 0)	/* issue a secure erase */
1271 #define BLKDEV_DISCARD_ZERO	(1 << 1)	/* must reliably zero data */
1272 
1273 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1274 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1275 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1276 extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1277 		sector_t nr_sects, gfp_t gfp_mask, int flags,
1278 		struct bio **biop);
1279 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1280 		sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1281 extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1282 		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
1283 		bool discard);
1284 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1285 		sector_t nr_sects, gfp_t gfp_mask, bool discard);
1286 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1287 		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1288 {
1289 	return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1290 				    nr_blocks << (sb->s_blocksize_bits - 9),
1291 				    gfp_mask, flags);
1292 }
1293 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1294 		sector_t nr_blocks, gfp_t gfp_mask)
1295 {
1296 	return blkdev_issue_zeroout(sb->s_bdev,
1297 				    block << (sb->s_blocksize_bits - 9),
1298 				    nr_blocks << (sb->s_blocksize_bits - 9),
1299 				    gfp_mask, true);
1300 }
1301 
1302 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1303 
1304 enum blk_default_limits {
1305 	BLK_MAX_SEGMENTS	= 128,
1306 	BLK_SAFE_MAX_SECTORS	= 255,
1307 	BLK_DEF_MAX_SECTORS	= 2560,
1308 	BLK_MAX_SEGMENT_SIZE	= 65536,
1309 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
1310 };
1311 
1312 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1313 
1314 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1315 {
1316 	return q->limits.bounce_pfn;
1317 }
1318 
1319 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1320 {
1321 	return q->limits.seg_boundary_mask;
1322 }
1323 
1324 static inline unsigned long queue_virt_boundary(struct request_queue *q)
1325 {
1326 	return q->limits.virt_boundary_mask;
1327 }
1328 
1329 static inline unsigned int queue_max_sectors(struct request_queue *q)
1330 {
1331 	return q->limits.max_sectors;
1332 }
1333 
1334 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1335 {
1336 	return q->limits.max_hw_sectors;
1337 }
1338 
1339 static inline unsigned short queue_max_segments(struct request_queue *q)
1340 {
1341 	return q->limits.max_segments;
1342 }
1343 
1344 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1345 {
1346 	return q->limits.max_segment_size;
1347 }
1348 
1349 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1350 {
1351 	int retval = 512;
1352 
1353 	if (q && q->limits.logical_block_size)
1354 		retval = q->limits.logical_block_size;
1355 
1356 	return retval;
1357 }
1358 
1359 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1360 {
1361 	return queue_logical_block_size(bdev_get_queue(bdev));
1362 }
1363 
1364 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1365 {
1366 	return q->limits.physical_block_size;
1367 }
1368 
1369 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1370 {
1371 	return queue_physical_block_size(bdev_get_queue(bdev));
1372 }
1373 
1374 static inline unsigned int queue_io_min(struct request_queue *q)
1375 {
1376 	return q->limits.io_min;
1377 }
1378 
1379 static inline int bdev_io_min(struct block_device *bdev)
1380 {
1381 	return queue_io_min(bdev_get_queue(bdev));
1382 }
1383 
1384 static inline unsigned int queue_io_opt(struct request_queue *q)
1385 {
1386 	return q->limits.io_opt;
1387 }
1388 
1389 static inline int bdev_io_opt(struct block_device *bdev)
1390 {
1391 	return queue_io_opt(bdev_get_queue(bdev));
1392 }
1393 
1394 static inline int queue_alignment_offset(struct request_queue *q)
1395 {
1396 	if (q->limits.misaligned)
1397 		return -1;
1398 
1399 	return q->limits.alignment_offset;
1400 }
1401 
1402 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1403 {
1404 	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1405 	unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
1406 
1407 	return (granularity + lim->alignment_offset - alignment) % granularity;
1408 }
1409 
1410 static inline int bdev_alignment_offset(struct block_device *bdev)
1411 {
1412 	struct request_queue *q = bdev_get_queue(bdev);
1413 
1414 	if (q->limits.misaligned)
1415 		return -1;
1416 
1417 	if (bdev != bdev->bd_contains)
1418 		return bdev->bd_part->alignment_offset;
1419 
1420 	return q->limits.alignment_offset;
1421 }
1422 
1423 static inline int queue_discard_alignment(struct request_queue *q)
1424 {
1425 	if (q->limits.discard_misaligned)
1426 		return -1;
1427 
1428 	return q->limits.discard_alignment;
1429 }
1430 
1431 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1432 {
1433 	unsigned int alignment, granularity, offset;
1434 
1435 	if (!lim->max_discard_sectors)
1436 		return 0;
1437 
1438 	/* Why are these in bytes, not sectors? */
1439 	alignment = lim->discard_alignment >> 9;
1440 	granularity = lim->discard_granularity >> 9;
1441 	if (!granularity)
1442 		return 0;
1443 
1444 	/* Offset of the partition start in 'granularity' sectors */
1445 	offset = sector_div(sector, granularity);
1446 
1447 	/* And why do we do this modulus *again* in blkdev_issue_discard()? */
1448 	offset = (granularity + alignment - offset) % granularity;
1449 
1450 	/* Turn it back into bytes, gaah */
1451 	return offset << 9;
1452 }
1453 
1454 static inline int bdev_discard_alignment(struct block_device *bdev)
1455 {
1456 	struct request_queue *q = bdev_get_queue(bdev);
1457 
1458 	if (bdev != bdev->bd_contains)
1459 		return bdev->bd_part->discard_alignment;
1460 
1461 	return q->limits.discard_alignment;
1462 }
1463 
1464 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1465 {
1466 	if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1467 		return 1;
1468 
1469 	return 0;
1470 }
1471 
1472 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1473 {
1474 	return queue_discard_zeroes_data(bdev_get_queue(bdev));
1475 }
1476 
1477 static inline unsigned int bdev_write_same(struct block_device *bdev)
1478 {
1479 	struct request_queue *q = bdev_get_queue(bdev);
1480 
1481 	if (q)
1482 		return q->limits.max_write_same_sectors;
1483 
1484 	return 0;
1485 }
1486 
1487 static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev)
1488 {
1489 	struct request_queue *q = bdev_get_queue(bdev);
1490 
1491 	if (q)
1492 		return q->limits.max_write_zeroes_sectors;
1493 
1494 	return 0;
1495 }
1496 
1497 static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev)
1498 {
1499 	struct request_queue *q = bdev_get_queue(bdev);
1500 
1501 	if (q)
1502 		return blk_queue_zoned_model(q);
1503 
1504 	return BLK_ZONED_NONE;
1505 }
1506 
1507 static inline bool bdev_is_zoned(struct block_device *bdev)
1508 {
1509 	struct request_queue *q = bdev_get_queue(bdev);
1510 
1511 	if (q)
1512 		return blk_queue_is_zoned(q);
1513 
1514 	return false;
1515 }
1516 
1517 static inline unsigned int bdev_zone_size(struct block_device *bdev)
1518 {
1519 	struct request_queue *q = bdev_get_queue(bdev);
1520 
1521 	if (q)
1522 		return blk_queue_zone_size(q);
1523 
1524 	return 0;
1525 }
1526 
1527 static inline int queue_dma_alignment(struct request_queue *q)
1528 {
1529 	return q ? q->dma_alignment : 511;
1530 }
1531 
1532 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1533 				 unsigned int len)
1534 {
1535 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1536 	return !(addr & alignment) && !(len & alignment);
1537 }
1538 
1539 /* assumes size > 256 */
1540 static inline unsigned int blksize_bits(unsigned int size)
1541 {
1542 	unsigned int bits = 8;
1543 	do {
1544 		bits++;
1545 		size >>= 1;
1546 	} while (size > 256);
1547 	return bits;
1548 }
1549 
1550 static inline unsigned int block_size(struct block_device *bdev)
1551 {
1552 	return bdev->bd_block_size;
1553 }
1554 
1555 static inline bool queue_flush_queueable(struct request_queue *q)
1556 {
1557 	return !test_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
1558 }
1559 
1560 typedef struct {struct page *v;} Sector;
1561 
1562 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1563 
1564 static inline void put_dev_sector(Sector p)
1565 {
1566 	put_page(p.v);
1567 }
1568 
1569 static inline bool __bvec_gap_to_prev(struct request_queue *q,
1570 				struct bio_vec *bprv, unsigned int offset)
1571 {
1572 	return offset ||
1573 		((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
1574 }
1575 
1576 /*
1577  * Check if adding a bio_vec after bprv with offset would create a gap in
1578  * the SG list. Most drivers don't care about this, but some do.
1579  */
1580 static inline bool bvec_gap_to_prev(struct request_queue *q,
1581 				struct bio_vec *bprv, unsigned int offset)
1582 {
1583 	if (!queue_virt_boundary(q))
1584 		return false;
1585 	return __bvec_gap_to_prev(q, bprv, offset);
1586 }
1587 
1588 static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
1589 			 struct bio *next)
1590 {
1591 	if (bio_has_data(prev) && queue_virt_boundary(q)) {
1592 		struct bio_vec pb, nb;
1593 
1594 		bio_get_last_bvec(prev, &pb);
1595 		bio_get_first_bvec(next, &nb);
1596 
1597 		return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
1598 	}
1599 
1600 	return false;
1601 }
1602 
1603 static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
1604 {
1605 	return bio_will_gap(req->q, req->biotail, bio);
1606 }
1607 
1608 static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
1609 {
1610 	return bio_will_gap(req->q, bio, req->bio);
1611 }
1612 
1613 int kblockd_schedule_work(struct work_struct *work);
1614 int kblockd_schedule_work_on(int cpu, struct work_struct *work);
1615 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
1616 int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1617 
1618 #ifdef CONFIG_BLK_CGROUP
1619 /*
1620  * This should not be using sched_clock(). A real patch is in progress
1621  * to fix this up, until that is in place we need to disable preemption
1622  * around sched_clock() in this function and set_io_start_time_ns().
1623  */
1624 static inline void set_start_time_ns(struct request *req)
1625 {
1626 	preempt_disable();
1627 	req->start_time_ns = sched_clock();
1628 	preempt_enable();
1629 }
1630 
1631 static inline void set_io_start_time_ns(struct request *req)
1632 {
1633 	preempt_disable();
1634 	req->io_start_time_ns = sched_clock();
1635 	preempt_enable();
1636 }
1637 
1638 static inline uint64_t rq_start_time_ns(struct request *req)
1639 {
1640         return req->start_time_ns;
1641 }
1642 
1643 static inline uint64_t rq_io_start_time_ns(struct request *req)
1644 {
1645         return req->io_start_time_ns;
1646 }
1647 #else
1648 static inline void set_start_time_ns(struct request *req) {}
1649 static inline void set_io_start_time_ns(struct request *req) {}
1650 static inline uint64_t rq_start_time_ns(struct request *req)
1651 {
1652 	return 0;
1653 }
1654 static inline uint64_t rq_io_start_time_ns(struct request *req)
1655 {
1656 	return 0;
1657 }
1658 #endif
1659 
1660 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1661 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1662 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1663 	MODULE_ALIAS("block-major-" __stringify(major) "-*")
1664 
1665 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1666 
1667 enum blk_integrity_flags {
1668 	BLK_INTEGRITY_VERIFY		= 1 << 0,
1669 	BLK_INTEGRITY_GENERATE		= 1 << 1,
1670 	BLK_INTEGRITY_DEVICE_CAPABLE	= 1 << 2,
1671 	BLK_INTEGRITY_IP_CHECKSUM	= 1 << 3,
1672 };
1673 
1674 struct blk_integrity_iter {
1675 	void			*prot_buf;
1676 	void			*data_buf;
1677 	sector_t		seed;
1678 	unsigned int		data_size;
1679 	unsigned short		interval;
1680 	const char		*disk_name;
1681 };
1682 
1683 typedef int (integrity_processing_fn) (struct blk_integrity_iter *);
1684 
1685 struct blk_integrity_profile {
1686 	integrity_processing_fn		*generate_fn;
1687 	integrity_processing_fn		*verify_fn;
1688 	const char			*name;
1689 };
1690 
1691 extern void blk_integrity_register(struct gendisk *, struct blk_integrity *);
1692 extern void blk_integrity_unregister(struct gendisk *);
1693 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1694 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1695 				   struct scatterlist *);
1696 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1697 extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
1698 				   struct request *);
1699 extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
1700 				    struct bio *);
1701 
1702 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1703 {
1704 	struct blk_integrity *bi = &disk->queue->integrity;
1705 
1706 	if (!bi->profile)
1707 		return NULL;
1708 
1709 	return bi;
1710 }
1711 
1712 static inline
1713 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1714 {
1715 	return blk_get_integrity(bdev->bd_disk);
1716 }
1717 
1718 static inline bool blk_integrity_rq(struct request *rq)
1719 {
1720 	return rq->cmd_flags & REQ_INTEGRITY;
1721 }
1722 
1723 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1724 						    unsigned int segs)
1725 {
1726 	q->limits.max_integrity_segments = segs;
1727 }
1728 
1729 static inline unsigned short
1730 queue_max_integrity_segments(struct request_queue *q)
1731 {
1732 	return q->limits.max_integrity_segments;
1733 }
1734 
1735 static inline bool integrity_req_gap_back_merge(struct request *req,
1736 						struct bio *next)
1737 {
1738 	struct bio_integrity_payload *bip = bio_integrity(req->bio);
1739 	struct bio_integrity_payload *bip_next = bio_integrity(next);
1740 
1741 	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1742 				bip_next->bip_vec[0].bv_offset);
1743 }
1744 
1745 static inline bool integrity_req_gap_front_merge(struct request *req,
1746 						 struct bio *bio)
1747 {
1748 	struct bio_integrity_payload *bip = bio_integrity(bio);
1749 	struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
1750 
1751 	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1752 				bip_next->bip_vec[0].bv_offset);
1753 }
1754 
1755 #else /* CONFIG_BLK_DEV_INTEGRITY */
1756 
1757 struct bio;
1758 struct block_device;
1759 struct gendisk;
1760 struct blk_integrity;
1761 
1762 static inline int blk_integrity_rq(struct request *rq)
1763 {
1764 	return 0;
1765 }
1766 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1767 					    struct bio *b)
1768 {
1769 	return 0;
1770 }
1771 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1772 					  struct bio *b,
1773 					  struct scatterlist *s)
1774 {
1775 	return 0;
1776 }
1777 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1778 {
1779 	return NULL;
1780 }
1781 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1782 {
1783 	return NULL;
1784 }
1785 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1786 {
1787 	return 0;
1788 }
1789 static inline void blk_integrity_register(struct gendisk *d,
1790 					 struct blk_integrity *b)
1791 {
1792 }
1793 static inline void blk_integrity_unregister(struct gendisk *d)
1794 {
1795 }
1796 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1797 						    unsigned int segs)
1798 {
1799 }
1800 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1801 {
1802 	return 0;
1803 }
1804 static inline bool blk_integrity_merge_rq(struct request_queue *rq,
1805 					  struct request *r1,
1806 					  struct request *r2)
1807 {
1808 	return true;
1809 }
1810 static inline bool blk_integrity_merge_bio(struct request_queue *rq,
1811 					   struct request *r,
1812 					   struct bio *b)
1813 {
1814 	return true;
1815 }
1816 
1817 static inline bool integrity_req_gap_back_merge(struct request *req,
1818 						struct bio *next)
1819 {
1820 	return false;
1821 }
1822 static inline bool integrity_req_gap_front_merge(struct request *req,
1823 						 struct bio *bio)
1824 {
1825 	return false;
1826 }
1827 
1828 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1829 
1830 /**
1831  * struct blk_dax_ctl - control and output parameters for ->direct_access
1832  * @sector: (input) offset relative to a block_device
1833  * @addr: (output) kernel virtual address for @sector populated by driver
1834  * @pfn: (output) page frame number for @addr populated by driver
1835  * @size: (input) number of bytes requested
1836  */
1837 struct blk_dax_ctl {
1838 	sector_t sector;
1839 	void *addr;
1840 	long size;
1841 	pfn_t pfn;
1842 };
1843 
1844 struct block_device_operations {
1845 	int (*open) (struct block_device *, fmode_t);
1846 	void (*release) (struct gendisk *, fmode_t);
1847 	int (*rw_page)(struct block_device *, sector_t, struct page *, bool);
1848 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1849 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1850 	long (*direct_access)(struct block_device *, sector_t, void **, pfn_t *,
1851 			long);
1852 	unsigned int (*check_events) (struct gendisk *disk,
1853 				      unsigned int clearing);
1854 	/* ->media_changed() is DEPRECATED, use ->check_events() instead */
1855 	int (*media_changed) (struct gendisk *);
1856 	void (*unlock_native_capacity) (struct gendisk *);
1857 	int (*revalidate_disk) (struct gendisk *);
1858 	int (*getgeo)(struct block_device *, struct hd_geometry *);
1859 	/* this callback is with swap_lock and sometimes page table lock held */
1860 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1861 	struct module *owner;
1862 	const struct pr_ops *pr_ops;
1863 };
1864 
1865 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1866 				 unsigned long);
1867 extern int bdev_read_page(struct block_device *, sector_t, struct page *);
1868 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
1869 						struct writeback_control *);
1870 extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *);
1871 extern int bdev_dax_supported(struct super_block *, int);
1872 extern bool bdev_dax_capable(struct block_device *);
1873 #else /* CONFIG_BLOCK */
1874 
1875 struct block_device;
1876 
1877 /*
1878  * stubs for when the block layer is configured out
1879  */
1880 #define buffer_heads_over_limit 0
1881 
1882 static inline long nr_blockdev_pages(void)
1883 {
1884 	return 0;
1885 }
1886 
1887 struct blk_plug {
1888 };
1889 
1890 static inline void blk_start_plug(struct blk_plug *plug)
1891 {
1892 }
1893 
1894 static inline void blk_finish_plug(struct blk_plug *plug)
1895 {
1896 }
1897 
1898 static inline void blk_flush_plug(struct task_struct *task)
1899 {
1900 }
1901 
1902 static inline void blk_schedule_flush_plug(struct task_struct *task)
1903 {
1904 }
1905 
1906 
1907 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1908 {
1909 	return false;
1910 }
1911 
1912 static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
1913 				     sector_t *error_sector)
1914 {
1915 	return 0;
1916 }
1917 
1918 #endif /* CONFIG_BLOCK */
1919 
1920 #endif
1921