xref: /linux-6.15/include/linux/blkdev.h (revision 1ccd4b7b)
1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
3 
4 #ifdef CONFIG_BLOCK
5 
6 #include <linux/sched.h>
7 #include <linux/major.h>
8 #include <linux/genhd.h>
9 #include <linux/list.h>
10 #include <linux/timer.h>
11 #include <linux/workqueue.h>
12 #include <linux/pagemap.h>
13 #include <linux/backing-dev.h>
14 #include <linux/wait.h>
15 #include <linux/mempool.h>
16 #include <linux/bio.h>
17 #include <linux/module.h>
18 #include <linux/stringify.h>
19 #include <linux/gfp.h>
20 #include <linux/bsg.h>
21 #include <linux/smp.h>
22 
23 #include <asm/scatterlist.h>
24 
25 struct scsi_ioctl_command;
26 
27 struct request_queue;
28 struct elevator_queue;
29 struct request_pm_state;
30 struct blk_trace;
31 struct request;
32 struct sg_io_hdr;
33 
34 #define BLKDEV_MIN_RQ	4
35 #define BLKDEV_MAX_RQ	128	/* Default maximum */
36 
37 struct request;
38 typedef void (rq_end_io_fn)(struct request *, int);
39 
40 struct request_list {
41 	/*
42 	 * count[], starved[], and wait[] are indexed by
43 	 * BLK_RW_SYNC/BLK_RW_ASYNC
44 	 */
45 	int count[2];
46 	int starved[2];
47 	int elvpriv;
48 	mempool_t *rq_pool;
49 	wait_queue_head_t wait[2];
50 };
51 
52 /*
53  * request command types
54  */
55 enum rq_cmd_type_bits {
56 	REQ_TYPE_FS		= 1,	/* fs request */
57 	REQ_TYPE_BLOCK_PC,		/* scsi command */
58 	REQ_TYPE_SENSE,			/* sense request */
59 	REQ_TYPE_PM_SUSPEND,		/* suspend request */
60 	REQ_TYPE_PM_RESUME,		/* resume request */
61 	REQ_TYPE_PM_SHUTDOWN,		/* shutdown request */
62 	REQ_TYPE_SPECIAL,		/* driver defined type */
63 	/*
64 	 * for ATA/ATAPI devices. this really doesn't belong here, ide should
65 	 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
66 	 * private REQ_LB opcodes to differentiate what type of request this is
67 	 */
68 	REQ_TYPE_ATA_TASKFILE,
69 	REQ_TYPE_ATA_PC,
70 };
71 
72 #define BLK_MAX_CDB	16
73 
74 /*
75  * try to put the fields that are referenced together in the same cacheline.
76  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
77  * as well!
78  */
79 struct request {
80 	struct list_head queuelist;
81 	struct call_single_data csd;
82 
83 	struct request_queue *q;
84 
85 	unsigned int cmd_flags;
86 	enum rq_cmd_type_bits cmd_type;
87 	unsigned long atomic_flags;
88 
89 	int cpu;
90 
91 	/* the following two fields are internal, NEVER access directly */
92 	unsigned int __data_len;	/* total data len */
93 	sector_t __sector;		/* sector cursor */
94 
95 	struct bio *bio;
96 	struct bio *biotail;
97 
98 	struct hlist_node hash;	/* merge hash */
99 	/*
100 	 * The rb_node is only used inside the io scheduler, requests
101 	 * are pruned when moved to the dispatch queue. So let the
102 	 * completion_data share space with the rb_node.
103 	 */
104 	union {
105 		struct rb_node rb_node;	/* sort/lookup */
106 		void *completion_data;
107 	};
108 
109 	/*
110 	 * Three pointers are available for the IO schedulers, if they need
111 	 * more they have to dynamically allocate it.  Flush requests are
112 	 * never put on the IO scheduler. So let the flush fields share
113 	 * space with the three elevator_private pointers.
114 	 */
115 	union {
116 		void *elevator_private[3];
117 		struct {
118 			unsigned int		seq;
119 			struct list_head	list;
120 		} flush;
121 	};
122 
123 	struct gendisk *rq_disk;
124 	struct hd_struct *part;
125 	unsigned long start_time;
126 #ifdef CONFIG_BLK_CGROUP
127 	unsigned long long start_time_ns;
128 	unsigned long long io_start_time_ns;    /* when passed to hardware */
129 #endif
130 	/* Number of scatter-gather DMA addr+len pairs after
131 	 * physical address coalescing is performed.
132 	 */
133 	unsigned short nr_phys_segments;
134 #if defined(CONFIG_BLK_DEV_INTEGRITY)
135 	unsigned short nr_integrity_segments;
136 #endif
137 
138 	unsigned short ioprio;
139 
140 	int ref_count;
141 
142 	void *special;		/* opaque pointer available for LLD use */
143 	char *buffer;		/* kaddr of the current segment if available */
144 
145 	int tag;
146 	int errors;
147 
148 	/*
149 	 * when request is used as a packet command carrier
150 	 */
151 	unsigned char __cmd[BLK_MAX_CDB];
152 	unsigned char *cmd;
153 	unsigned short cmd_len;
154 
155 	unsigned int extra_len;	/* length of alignment and padding */
156 	unsigned int sense_len;
157 	unsigned int resid_len;	/* residual count */
158 	void *sense;
159 
160 	unsigned long deadline;
161 	struct list_head timeout_list;
162 	unsigned int timeout;
163 	int retries;
164 
165 	/*
166 	 * completion callback.
167 	 */
168 	rq_end_io_fn *end_io;
169 	void *end_io_data;
170 
171 	/* for bidi */
172 	struct request *next_rq;
173 };
174 
175 static inline unsigned short req_get_ioprio(struct request *req)
176 {
177 	return req->ioprio;
178 }
179 
180 /*
181  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
182  * requests. Some step values could eventually be made generic.
183  */
184 struct request_pm_state
185 {
186 	/* PM state machine step value, currently driver specific */
187 	int	pm_step;
188 	/* requested PM state value (S1, S2, S3, S4, ...) */
189 	u32	pm_state;
190 	void*	data;		/* for driver use */
191 };
192 
193 #include <linux/elevator.h>
194 
195 typedef void (request_fn_proc) (struct request_queue *q);
196 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
197 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
198 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
199 
200 struct bio_vec;
201 struct bvec_merge_data {
202 	struct block_device *bi_bdev;
203 	sector_t bi_sector;
204 	unsigned bi_size;
205 	unsigned long bi_rw;
206 };
207 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
208 			     struct bio_vec *);
209 typedef void (softirq_done_fn)(struct request *);
210 typedef int (dma_drain_needed_fn)(struct request *);
211 typedef int (lld_busy_fn) (struct request_queue *q);
212 
213 enum blk_eh_timer_return {
214 	BLK_EH_NOT_HANDLED,
215 	BLK_EH_HANDLED,
216 	BLK_EH_RESET_TIMER,
217 };
218 
219 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
220 
221 enum blk_queue_state {
222 	Queue_down,
223 	Queue_up,
224 };
225 
226 struct blk_queue_tag {
227 	struct request **tag_index;	/* map of busy tags */
228 	unsigned long *tag_map;		/* bit map of free/busy tags */
229 	int busy;			/* current depth */
230 	int max_depth;			/* what we will send to device */
231 	int real_max_depth;		/* what the array can hold */
232 	atomic_t refcnt;		/* map can be shared */
233 };
234 
235 #define BLK_SCSI_MAX_CMDS	(256)
236 #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
237 
238 struct queue_limits {
239 	unsigned long		bounce_pfn;
240 	unsigned long		seg_boundary_mask;
241 
242 	unsigned int		max_hw_sectors;
243 	unsigned int		max_sectors;
244 	unsigned int		max_segment_size;
245 	unsigned int		physical_block_size;
246 	unsigned int		alignment_offset;
247 	unsigned int		io_min;
248 	unsigned int		io_opt;
249 	unsigned int		max_discard_sectors;
250 	unsigned int		discard_granularity;
251 	unsigned int		discard_alignment;
252 
253 	unsigned short		logical_block_size;
254 	unsigned short		max_segments;
255 	unsigned short		max_integrity_segments;
256 
257 	unsigned char		misaligned;
258 	unsigned char		discard_misaligned;
259 	unsigned char		cluster;
260 	unsigned char		discard_zeroes_data;
261 };
262 
263 struct request_queue {
264 	/*
265 	 * Together with queue_head for cacheline sharing
266 	 */
267 	struct list_head	queue_head;
268 	struct request		*last_merge;
269 	struct elevator_queue	*elevator;
270 
271 	/*
272 	 * the queue request freelist, one for reads and one for writes
273 	 */
274 	struct request_list	rq;
275 
276 	request_fn_proc		*request_fn;
277 	make_request_fn		*make_request_fn;
278 	prep_rq_fn		*prep_rq_fn;
279 	unprep_rq_fn		*unprep_rq_fn;
280 	merge_bvec_fn		*merge_bvec_fn;
281 	softirq_done_fn		*softirq_done_fn;
282 	rq_timed_out_fn		*rq_timed_out_fn;
283 	dma_drain_needed_fn	*dma_drain_needed;
284 	lld_busy_fn		*lld_busy_fn;
285 
286 	/*
287 	 * Dispatch queue sorting
288 	 */
289 	sector_t		end_sector;
290 	struct request		*boundary_rq;
291 
292 	/*
293 	 * Delayed queue handling
294 	 */
295 	struct delayed_work	delay_work;
296 
297 	struct backing_dev_info	backing_dev_info;
298 
299 	/*
300 	 * The queue owner gets to use this for whatever they like.
301 	 * ll_rw_blk doesn't touch it.
302 	 */
303 	void			*queuedata;
304 
305 	/*
306 	 * various queue flags, see QUEUE_* below
307 	 */
308 	unsigned long		queue_flags;
309 
310 	/*
311 	 * queue needs bounce pages for pages above this limit
312 	 */
313 	gfp_t			bounce_gfp;
314 
315 	/*
316 	 * protects queue structures from reentrancy. ->__queue_lock should
317 	 * _never_ be used directly, it is queue private. always use
318 	 * ->queue_lock.
319 	 */
320 	spinlock_t		__queue_lock;
321 	spinlock_t		*queue_lock;
322 
323 	/*
324 	 * queue kobject
325 	 */
326 	struct kobject kobj;
327 
328 	/*
329 	 * queue settings
330 	 */
331 	unsigned long		nr_requests;	/* Max # of requests */
332 	unsigned int		nr_congestion_on;
333 	unsigned int		nr_congestion_off;
334 	unsigned int		nr_batching;
335 
336 	unsigned int		dma_drain_size;
337 	void			*dma_drain_buffer;
338 	unsigned int		dma_pad_mask;
339 	unsigned int		dma_alignment;
340 
341 	struct blk_queue_tag	*queue_tags;
342 	struct list_head	tag_busy_list;
343 
344 	unsigned int		nr_sorted;
345 	unsigned int		in_flight[2];
346 
347 	unsigned int		rq_timeout;
348 	struct timer_list	timeout;
349 	struct list_head	timeout_list;
350 
351 	struct queue_limits	limits;
352 
353 	/*
354 	 * sg stuff
355 	 */
356 	unsigned int		sg_timeout;
357 	unsigned int		sg_reserved_size;
358 	int			node;
359 #ifdef CONFIG_BLK_DEV_IO_TRACE
360 	struct blk_trace	*blk_trace;
361 #endif
362 	/*
363 	 * for flush operations
364 	 */
365 	unsigned int		flush_flags;
366 	unsigned int		flush_not_queueable:1;
367 	unsigned int		flush_queue_delayed:1;
368 	unsigned int		flush_pending_idx:1;
369 	unsigned int		flush_running_idx:1;
370 	unsigned long		flush_pending_since;
371 	struct list_head	flush_queue[2];
372 	struct list_head	flush_data_in_flight;
373 	struct request		flush_rq;
374 
375 	struct mutex		sysfs_lock;
376 
377 #if defined(CONFIG_BLK_DEV_BSG)
378 	struct bsg_class_device bsg_dev;
379 #endif
380 
381 #ifdef CONFIG_BLK_DEV_THROTTLING
382 	/* Throttle data */
383 	struct throtl_data *td;
384 #endif
385 };
386 
387 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
388 #define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
389 #define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
390 #define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
391 #define QUEUE_FLAG_DEAD		5	/* queue being torn down */
392 #define QUEUE_FLAG_ELVSWITCH	6	/* don't use elevator, just do FIFO */
393 #define QUEUE_FLAG_BIDI		7	/* queue supports bidi requests */
394 #define QUEUE_FLAG_NOMERGES     8	/* disable merge attempts */
395 #define QUEUE_FLAG_SAME_COMP	9	/* complete on same CPU-group */
396 #define QUEUE_FLAG_FAIL_IO     10	/* fake timeout */
397 #define QUEUE_FLAG_STACKABLE   11	/* supports request stacking */
398 #define QUEUE_FLAG_NONROT      12	/* non-rotational device (SSD) */
399 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
400 #define QUEUE_FLAG_IO_STAT     13	/* do IO stats */
401 #define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
402 #define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
403 #define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
404 #define QUEUE_FLAG_SECDISCARD  17	/* supports SECDISCARD */
405 #define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
406 
407 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
408 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
409 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
410 				 (1 << QUEUE_FLAG_ADD_RANDOM))
411 
412 static inline int queue_is_locked(struct request_queue *q)
413 {
414 #ifdef CONFIG_SMP
415 	spinlock_t *lock = q->queue_lock;
416 	return lock && spin_is_locked(lock);
417 #else
418 	return 1;
419 #endif
420 }
421 
422 static inline void queue_flag_set_unlocked(unsigned int flag,
423 					   struct request_queue *q)
424 {
425 	__set_bit(flag, &q->queue_flags);
426 }
427 
428 static inline int queue_flag_test_and_clear(unsigned int flag,
429 					    struct request_queue *q)
430 {
431 	WARN_ON_ONCE(!queue_is_locked(q));
432 
433 	if (test_bit(flag, &q->queue_flags)) {
434 		__clear_bit(flag, &q->queue_flags);
435 		return 1;
436 	}
437 
438 	return 0;
439 }
440 
441 static inline int queue_flag_test_and_set(unsigned int flag,
442 					  struct request_queue *q)
443 {
444 	WARN_ON_ONCE(!queue_is_locked(q));
445 
446 	if (!test_bit(flag, &q->queue_flags)) {
447 		__set_bit(flag, &q->queue_flags);
448 		return 0;
449 	}
450 
451 	return 1;
452 }
453 
454 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
455 {
456 	WARN_ON_ONCE(!queue_is_locked(q));
457 	__set_bit(flag, &q->queue_flags);
458 }
459 
460 static inline void queue_flag_clear_unlocked(unsigned int flag,
461 					     struct request_queue *q)
462 {
463 	__clear_bit(flag, &q->queue_flags);
464 }
465 
466 static inline int queue_in_flight(struct request_queue *q)
467 {
468 	return q->in_flight[0] + q->in_flight[1];
469 }
470 
471 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
472 {
473 	WARN_ON_ONCE(!queue_is_locked(q));
474 	__clear_bit(flag, &q->queue_flags);
475 }
476 
477 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
478 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
479 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
480 #define blk_queue_noxmerges(q)	\
481 	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
482 #define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
483 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
484 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
485 #define blk_queue_stackable(q)	\
486 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
487 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
488 #define blk_queue_secdiscard(q)	(blk_queue_discard(q) && \
489 	test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
490 
491 #define blk_noretry_request(rq) \
492 	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
493 			     REQ_FAILFAST_DRIVER))
494 
495 #define blk_account_rq(rq) \
496 	(((rq)->cmd_flags & REQ_STARTED) && \
497 	 ((rq)->cmd_type == REQ_TYPE_FS || \
498 	  ((rq)->cmd_flags & REQ_DISCARD)))
499 
500 #define blk_pm_request(rq)	\
501 	((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
502 	 (rq)->cmd_type == REQ_TYPE_PM_RESUME)
503 
504 #define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
505 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
506 /* rq->queuelist of dequeued request must be list_empty() */
507 #define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
508 
509 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
510 
511 #define rq_data_dir(rq)		((rq)->cmd_flags & 1)
512 
513 static inline unsigned int blk_queue_cluster(struct request_queue *q)
514 {
515 	return q->limits.cluster;
516 }
517 
518 /*
519  * We regard a request as sync, if either a read or a sync write
520  */
521 static inline bool rw_is_sync(unsigned int rw_flags)
522 {
523 	return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
524 }
525 
526 static inline bool rq_is_sync(struct request *rq)
527 {
528 	return rw_is_sync(rq->cmd_flags);
529 }
530 
531 static inline int blk_queue_full(struct request_queue *q, int sync)
532 {
533 	if (sync)
534 		return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
535 	return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
536 }
537 
538 static inline void blk_set_queue_full(struct request_queue *q, int sync)
539 {
540 	if (sync)
541 		queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
542 	else
543 		queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
544 }
545 
546 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
547 {
548 	if (sync)
549 		queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
550 	else
551 		queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
552 }
553 
554 
555 /*
556  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
557  * it already be started by driver.
558  */
559 #define RQ_NOMERGE_FLAGS	\
560 	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
561 #define rq_mergeable(rq)	\
562 	(!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
563 	 (((rq)->cmd_flags & REQ_DISCARD) || \
564 	  (rq)->cmd_type == REQ_TYPE_FS))
565 
566 /*
567  * q->prep_rq_fn return values
568  */
569 #define BLKPREP_OK		0	/* serve it */
570 #define BLKPREP_KILL		1	/* fatal error, kill */
571 #define BLKPREP_DEFER		2	/* leave on queue */
572 
573 extern unsigned long blk_max_low_pfn, blk_max_pfn;
574 
575 /*
576  * standard bounce addresses:
577  *
578  * BLK_BOUNCE_HIGH	: bounce all highmem pages
579  * BLK_BOUNCE_ANY	: don't bounce anything
580  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
581  */
582 
583 #if BITS_PER_LONG == 32
584 #define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
585 #else
586 #define BLK_BOUNCE_HIGH		-1ULL
587 #endif
588 #define BLK_BOUNCE_ANY		(-1ULL)
589 #define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
590 
591 /*
592  * default timeout for SG_IO if none specified
593  */
594 #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
595 #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
596 
597 #ifdef CONFIG_BOUNCE
598 extern int init_emergency_isa_pool(void);
599 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
600 #else
601 static inline int init_emergency_isa_pool(void)
602 {
603 	return 0;
604 }
605 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
606 {
607 }
608 #endif /* CONFIG_MMU */
609 
610 struct rq_map_data {
611 	struct page **pages;
612 	int page_order;
613 	int nr_entries;
614 	unsigned long offset;
615 	int null_mapped;
616 	int from_user;
617 };
618 
619 struct req_iterator {
620 	int i;
621 	struct bio *bio;
622 };
623 
624 /* This should not be used directly - use rq_for_each_segment */
625 #define for_each_bio(_bio)		\
626 	for (; _bio; _bio = _bio->bi_next)
627 #define __rq_for_each_bio(_bio, rq)	\
628 	if ((rq->bio))			\
629 		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
630 
631 #define rq_for_each_segment(bvl, _rq, _iter)			\
632 	__rq_for_each_bio(_iter.bio, _rq)			\
633 		bio_for_each_segment(bvl, _iter.bio, _iter.i)
634 
635 #define rq_iter_last(rq, _iter)					\
636 		(_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
637 
638 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
639 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
640 #endif
641 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
642 extern void rq_flush_dcache_pages(struct request *rq);
643 #else
644 static inline void rq_flush_dcache_pages(struct request *rq)
645 {
646 }
647 #endif
648 
649 extern int blk_register_queue(struct gendisk *disk);
650 extern void blk_unregister_queue(struct gendisk *disk);
651 extern void generic_make_request(struct bio *bio);
652 extern void blk_rq_init(struct request_queue *q, struct request *rq);
653 extern void blk_put_request(struct request *);
654 extern void __blk_put_request(struct request_queue *, struct request *);
655 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
656 extern struct request *blk_make_request(struct request_queue *, struct bio *,
657 					gfp_t);
658 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
659 extern void blk_requeue_request(struct request_queue *, struct request *);
660 extern void blk_add_request_payload(struct request *rq, struct page *page,
661 		unsigned int len);
662 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
663 extern int blk_lld_busy(struct request_queue *q);
664 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
665 			     struct bio_set *bs, gfp_t gfp_mask,
666 			     int (*bio_ctr)(struct bio *, struct bio *, void *),
667 			     void *data);
668 extern void blk_rq_unprep_clone(struct request *rq);
669 extern int blk_insert_cloned_request(struct request_queue *q,
670 				     struct request *rq);
671 extern void blk_delay_queue(struct request_queue *, unsigned long);
672 extern void blk_recount_segments(struct request_queue *, struct bio *);
673 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
674 			  unsigned int, void __user *);
675 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
676 			 struct scsi_ioctl_command __user *);
677 
678 /*
679  * A queue has just exitted congestion.  Note this in the global counter of
680  * congested queues, and wake up anyone who was waiting for requests to be
681  * put back.
682  */
683 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
684 {
685 	clear_bdi_congested(&q->backing_dev_info, sync);
686 }
687 
688 /*
689  * A queue has just entered congestion.  Flag that in the queue's VM-visible
690  * state flags and increment the global gounter of congested queues.
691  */
692 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
693 {
694 	set_bdi_congested(&q->backing_dev_info, sync);
695 }
696 
697 extern void blk_start_queue(struct request_queue *q);
698 extern void blk_stop_queue(struct request_queue *q);
699 extern void blk_sync_queue(struct request_queue *q);
700 extern void __blk_stop_queue(struct request_queue *q);
701 extern void __blk_run_queue(struct request_queue *q);
702 extern void blk_run_queue(struct request_queue *);
703 extern void blk_run_queue_async(struct request_queue *q);
704 extern int blk_rq_map_user(struct request_queue *, struct request *,
705 			   struct rq_map_data *, void __user *, unsigned long,
706 			   gfp_t);
707 extern int blk_rq_unmap_user(struct bio *);
708 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
709 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
710 			       struct rq_map_data *, struct sg_iovec *, int,
711 			       unsigned int, gfp_t);
712 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
713 			  struct request *, int);
714 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
715 				  struct request *, int, rq_end_io_fn *);
716 
717 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
718 {
719 	return bdev->bd_disk->queue;
720 }
721 
722 /*
723  * blk_rq_pos()			: the current sector
724  * blk_rq_bytes()		: bytes left in the entire request
725  * blk_rq_cur_bytes()		: bytes left in the current segment
726  * blk_rq_err_bytes()		: bytes left till the next error boundary
727  * blk_rq_sectors()		: sectors left in the entire request
728  * blk_rq_cur_sectors()		: sectors left in the current segment
729  */
730 static inline sector_t blk_rq_pos(const struct request *rq)
731 {
732 	return rq->__sector;
733 }
734 
735 static inline unsigned int blk_rq_bytes(const struct request *rq)
736 {
737 	return rq->__data_len;
738 }
739 
740 static inline int blk_rq_cur_bytes(const struct request *rq)
741 {
742 	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
743 }
744 
745 extern unsigned int blk_rq_err_bytes(const struct request *rq);
746 
747 static inline unsigned int blk_rq_sectors(const struct request *rq)
748 {
749 	return blk_rq_bytes(rq) >> 9;
750 }
751 
752 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
753 {
754 	return blk_rq_cur_bytes(rq) >> 9;
755 }
756 
757 /*
758  * Request issue related functions.
759  */
760 extern struct request *blk_peek_request(struct request_queue *q);
761 extern void blk_start_request(struct request *rq);
762 extern struct request *blk_fetch_request(struct request_queue *q);
763 
764 /*
765  * Request completion related functions.
766  *
767  * blk_update_request() completes given number of bytes and updates
768  * the request without completing it.
769  *
770  * blk_end_request() and friends.  __blk_end_request() must be called
771  * with the request queue spinlock acquired.
772  *
773  * Several drivers define their own end_request and call
774  * blk_end_request() for parts of the original function.
775  * This prevents code duplication in drivers.
776  */
777 extern bool blk_update_request(struct request *rq, int error,
778 			       unsigned int nr_bytes);
779 extern bool blk_end_request(struct request *rq, int error,
780 			    unsigned int nr_bytes);
781 extern void blk_end_request_all(struct request *rq, int error);
782 extern bool blk_end_request_cur(struct request *rq, int error);
783 extern bool blk_end_request_err(struct request *rq, int error);
784 extern bool __blk_end_request(struct request *rq, int error,
785 			      unsigned int nr_bytes);
786 extern void __blk_end_request_all(struct request *rq, int error);
787 extern bool __blk_end_request_cur(struct request *rq, int error);
788 extern bool __blk_end_request_err(struct request *rq, int error);
789 
790 extern void blk_complete_request(struct request *);
791 extern void __blk_complete_request(struct request *);
792 extern void blk_abort_request(struct request *);
793 extern void blk_abort_queue(struct request_queue *);
794 extern void blk_unprep_request(struct request *);
795 
796 /*
797  * Access functions for manipulating queue properties
798  */
799 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
800 					spinlock_t *lock, int node_id);
801 extern struct request_queue *blk_init_allocated_queue_node(struct request_queue *,
802 							   request_fn_proc *,
803 							   spinlock_t *, int node_id);
804 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
805 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
806 						      request_fn_proc *, spinlock_t *);
807 extern void blk_cleanup_queue(struct request_queue *);
808 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
809 extern void blk_queue_bounce_limit(struct request_queue *, u64);
810 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
811 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
812 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
813 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
814 extern void blk_queue_max_discard_sectors(struct request_queue *q,
815 		unsigned int max_discard_sectors);
816 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
817 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
818 extern void blk_queue_alignment_offset(struct request_queue *q,
819 				       unsigned int alignment);
820 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
821 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
822 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
823 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
824 extern void blk_set_default_limits(struct queue_limits *lim);
825 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
826 			    sector_t offset);
827 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
828 			    sector_t offset);
829 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
830 			      sector_t offset);
831 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
832 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
833 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
834 extern int blk_queue_dma_drain(struct request_queue *q,
835 			       dma_drain_needed_fn *dma_drain_needed,
836 			       void *buf, unsigned int size);
837 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
838 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
839 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
840 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
841 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
842 extern void blk_queue_dma_alignment(struct request_queue *, int);
843 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
844 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
845 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
846 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
847 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
848 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
849 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
850 
851 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
852 extern void blk_dump_rq_flags(struct request *, char *);
853 extern long nr_blockdev_pages(void);
854 
855 int blk_get_queue(struct request_queue *);
856 struct request_queue *blk_alloc_queue(gfp_t);
857 struct request_queue *blk_alloc_queue_node(gfp_t, int);
858 extern void blk_put_queue(struct request_queue *);
859 
860 /*
861  * Note: Code in between changing the blk_plug list/cb_list or element of such
862  * lists is preemptable, but such code can't do sleep (or be very careful),
863  * otherwise data is corrupted. For details, please check schedule() where
864  * blk_schedule_flush_plug() is called.
865  */
866 struct blk_plug {
867 	unsigned long magic;
868 	struct list_head list;
869 	struct list_head cb_list;
870 	unsigned int should_sort;
871 	unsigned int count;
872 };
873 #define BLK_MAX_REQUEST_COUNT 16
874 
875 struct blk_plug_cb {
876 	struct list_head list;
877 	void (*callback)(struct blk_plug_cb *);
878 };
879 
880 extern void blk_start_plug(struct blk_plug *);
881 extern void blk_finish_plug(struct blk_plug *);
882 extern void blk_flush_plug_list(struct blk_plug *, bool);
883 
884 static inline void blk_flush_plug(struct task_struct *tsk)
885 {
886 	struct blk_plug *plug = tsk->plug;
887 
888 	if (plug)
889 		blk_flush_plug_list(plug, false);
890 }
891 
892 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
893 {
894 	struct blk_plug *plug = tsk->plug;
895 
896 	if (plug)
897 		blk_flush_plug_list(plug, true);
898 }
899 
900 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
901 {
902 	struct blk_plug *plug = tsk->plug;
903 
904 	return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
905 }
906 
907 /*
908  * tag stuff
909  */
910 #define blk_rq_tagged(rq)		((rq)->cmd_flags & REQ_QUEUED)
911 extern int blk_queue_start_tag(struct request_queue *, struct request *);
912 extern struct request *blk_queue_find_tag(struct request_queue *, int);
913 extern void blk_queue_end_tag(struct request_queue *, struct request *);
914 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
915 extern void blk_queue_free_tags(struct request_queue *);
916 extern int blk_queue_resize_tags(struct request_queue *, int);
917 extern void blk_queue_invalidate_tags(struct request_queue *);
918 extern struct blk_queue_tag *blk_init_tags(int);
919 extern void blk_free_tags(struct blk_queue_tag *);
920 
921 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
922 						int tag)
923 {
924 	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
925 		return NULL;
926 	return bqt->tag_index[tag];
927 }
928 
929 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
930 
931 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
932 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
933 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
934 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
935 			sector_t nr_sects, gfp_t gfp_mask);
936 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
937 		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
938 {
939 	return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
940 				    nr_blocks << (sb->s_blocksize_bits - 9),
941 				    gfp_mask, flags);
942 }
943 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
944 		sector_t nr_blocks, gfp_t gfp_mask)
945 {
946 	return blkdev_issue_zeroout(sb->s_bdev,
947 				    block << (sb->s_blocksize_bits - 9),
948 				    nr_blocks << (sb->s_blocksize_bits - 9),
949 				    gfp_mask);
950 }
951 
952 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
953 
954 enum blk_default_limits {
955 	BLK_MAX_SEGMENTS	= 128,
956 	BLK_SAFE_MAX_SECTORS	= 255,
957 	BLK_DEF_MAX_SECTORS	= 1024,
958 	BLK_MAX_SEGMENT_SIZE	= 65536,
959 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
960 };
961 
962 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
963 
964 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
965 {
966 	return q->limits.bounce_pfn;
967 }
968 
969 static inline unsigned long queue_segment_boundary(struct request_queue *q)
970 {
971 	return q->limits.seg_boundary_mask;
972 }
973 
974 static inline unsigned int queue_max_sectors(struct request_queue *q)
975 {
976 	return q->limits.max_sectors;
977 }
978 
979 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
980 {
981 	return q->limits.max_hw_sectors;
982 }
983 
984 static inline unsigned short queue_max_segments(struct request_queue *q)
985 {
986 	return q->limits.max_segments;
987 }
988 
989 static inline unsigned int queue_max_segment_size(struct request_queue *q)
990 {
991 	return q->limits.max_segment_size;
992 }
993 
994 static inline unsigned short queue_logical_block_size(struct request_queue *q)
995 {
996 	int retval = 512;
997 
998 	if (q && q->limits.logical_block_size)
999 		retval = q->limits.logical_block_size;
1000 
1001 	return retval;
1002 }
1003 
1004 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1005 {
1006 	return queue_logical_block_size(bdev_get_queue(bdev));
1007 }
1008 
1009 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1010 {
1011 	return q->limits.physical_block_size;
1012 }
1013 
1014 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1015 {
1016 	return queue_physical_block_size(bdev_get_queue(bdev));
1017 }
1018 
1019 static inline unsigned int queue_io_min(struct request_queue *q)
1020 {
1021 	return q->limits.io_min;
1022 }
1023 
1024 static inline int bdev_io_min(struct block_device *bdev)
1025 {
1026 	return queue_io_min(bdev_get_queue(bdev));
1027 }
1028 
1029 static inline unsigned int queue_io_opt(struct request_queue *q)
1030 {
1031 	return q->limits.io_opt;
1032 }
1033 
1034 static inline int bdev_io_opt(struct block_device *bdev)
1035 {
1036 	return queue_io_opt(bdev_get_queue(bdev));
1037 }
1038 
1039 static inline int queue_alignment_offset(struct request_queue *q)
1040 {
1041 	if (q->limits.misaligned)
1042 		return -1;
1043 
1044 	return q->limits.alignment_offset;
1045 }
1046 
1047 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1048 {
1049 	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1050 	unsigned int alignment = (sector << 9) & (granularity - 1);
1051 
1052 	return (granularity + lim->alignment_offset - alignment)
1053 		& (granularity - 1);
1054 }
1055 
1056 static inline int bdev_alignment_offset(struct block_device *bdev)
1057 {
1058 	struct request_queue *q = bdev_get_queue(bdev);
1059 
1060 	if (q->limits.misaligned)
1061 		return -1;
1062 
1063 	if (bdev != bdev->bd_contains)
1064 		return bdev->bd_part->alignment_offset;
1065 
1066 	return q->limits.alignment_offset;
1067 }
1068 
1069 static inline int queue_discard_alignment(struct request_queue *q)
1070 {
1071 	if (q->limits.discard_misaligned)
1072 		return -1;
1073 
1074 	return q->limits.discard_alignment;
1075 }
1076 
1077 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1078 {
1079 	unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1080 
1081 	if (!lim->max_discard_sectors)
1082 		return 0;
1083 
1084 	return (lim->discard_granularity + lim->discard_alignment - alignment)
1085 		& (lim->discard_granularity - 1);
1086 }
1087 
1088 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1089 {
1090 	if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1091 		return 1;
1092 
1093 	return 0;
1094 }
1095 
1096 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1097 {
1098 	return queue_discard_zeroes_data(bdev_get_queue(bdev));
1099 }
1100 
1101 static inline int queue_dma_alignment(struct request_queue *q)
1102 {
1103 	return q ? q->dma_alignment : 511;
1104 }
1105 
1106 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1107 				 unsigned int len)
1108 {
1109 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1110 	return !(addr & alignment) && !(len & alignment);
1111 }
1112 
1113 /* assumes size > 256 */
1114 static inline unsigned int blksize_bits(unsigned int size)
1115 {
1116 	unsigned int bits = 8;
1117 	do {
1118 		bits++;
1119 		size >>= 1;
1120 	} while (size > 256);
1121 	return bits;
1122 }
1123 
1124 static inline unsigned int block_size(struct block_device *bdev)
1125 {
1126 	return bdev->bd_block_size;
1127 }
1128 
1129 static inline bool queue_flush_queueable(struct request_queue *q)
1130 {
1131 	return !q->flush_not_queueable;
1132 }
1133 
1134 typedef struct {struct page *v;} Sector;
1135 
1136 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1137 
1138 static inline void put_dev_sector(Sector p)
1139 {
1140 	page_cache_release(p.v);
1141 }
1142 
1143 struct work_struct;
1144 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1145 
1146 #ifdef CONFIG_BLK_CGROUP
1147 /*
1148  * This should not be using sched_clock(). A real patch is in progress
1149  * to fix this up, until that is in place we need to disable preemption
1150  * around sched_clock() in this function and set_io_start_time_ns().
1151  */
1152 static inline void set_start_time_ns(struct request *req)
1153 {
1154 	preempt_disable();
1155 	req->start_time_ns = sched_clock();
1156 	preempt_enable();
1157 }
1158 
1159 static inline void set_io_start_time_ns(struct request *req)
1160 {
1161 	preempt_disable();
1162 	req->io_start_time_ns = sched_clock();
1163 	preempt_enable();
1164 }
1165 
1166 static inline uint64_t rq_start_time_ns(struct request *req)
1167 {
1168         return req->start_time_ns;
1169 }
1170 
1171 static inline uint64_t rq_io_start_time_ns(struct request *req)
1172 {
1173         return req->io_start_time_ns;
1174 }
1175 #else
1176 static inline void set_start_time_ns(struct request *req) {}
1177 static inline void set_io_start_time_ns(struct request *req) {}
1178 static inline uint64_t rq_start_time_ns(struct request *req)
1179 {
1180 	return 0;
1181 }
1182 static inline uint64_t rq_io_start_time_ns(struct request *req)
1183 {
1184 	return 0;
1185 }
1186 #endif
1187 
1188 #ifdef CONFIG_BLK_DEV_THROTTLING
1189 extern int blk_throtl_init(struct request_queue *q);
1190 extern void blk_throtl_exit(struct request_queue *q);
1191 extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
1192 #else /* CONFIG_BLK_DEV_THROTTLING */
1193 static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
1194 {
1195 	return 0;
1196 }
1197 
1198 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
1199 static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
1200 #endif /* CONFIG_BLK_DEV_THROTTLING */
1201 
1202 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1203 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1204 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1205 	MODULE_ALIAS("block-major-" __stringify(major) "-*")
1206 
1207 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1208 
1209 #define INTEGRITY_FLAG_READ	2	/* verify data integrity on read */
1210 #define INTEGRITY_FLAG_WRITE	4	/* generate data integrity on write */
1211 
1212 struct blk_integrity_exchg {
1213 	void			*prot_buf;
1214 	void			*data_buf;
1215 	sector_t		sector;
1216 	unsigned int		data_size;
1217 	unsigned short		sector_size;
1218 	const char		*disk_name;
1219 };
1220 
1221 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1222 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1223 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1224 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1225 
1226 struct blk_integrity {
1227 	integrity_gen_fn	*generate_fn;
1228 	integrity_vrfy_fn	*verify_fn;
1229 	integrity_set_tag_fn	*set_tag_fn;
1230 	integrity_get_tag_fn	*get_tag_fn;
1231 
1232 	unsigned short		flags;
1233 	unsigned short		tuple_size;
1234 	unsigned short		sector_size;
1235 	unsigned short		tag_size;
1236 
1237 	const char		*name;
1238 
1239 	struct kobject		kobj;
1240 };
1241 
1242 extern bool blk_integrity_is_initialized(struct gendisk *);
1243 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1244 extern void blk_integrity_unregister(struct gendisk *);
1245 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1246 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1247 				   struct scatterlist *);
1248 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1249 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1250 				  struct request *);
1251 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1252 				   struct bio *);
1253 
1254 static inline
1255 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1256 {
1257 	return bdev->bd_disk->integrity;
1258 }
1259 
1260 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1261 {
1262 	return disk->integrity;
1263 }
1264 
1265 static inline int blk_integrity_rq(struct request *rq)
1266 {
1267 	if (rq->bio == NULL)
1268 		return 0;
1269 
1270 	return bio_integrity(rq->bio);
1271 }
1272 
1273 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1274 						    unsigned int segs)
1275 {
1276 	q->limits.max_integrity_segments = segs;
1277 }
1278 
1279 static inline unsigned short
1280 queue_max_integrity_segments(struct request_queue *q)
1281 {
1282 	return q->limits.max_integrity_segments;
1283 }
1284 
1285 #else /* CONFIG_BLK_DEV_INTEGRITY */
1286 
1287 #define blk_integrity_rq(rq)			(0)
1288 #define blk_rq_count_integrity_sg(a, b)		(0)
1289 #define blk_rq_map_integrity_sg(a, b, c)	(0)
1290 #define bdev_get_integrity(a)			(0)
1291 #define blk_get_integrity(a)			(0)
1292 #define blk_integrity_compare(a, b)		(0)
1293 #define blk_integrity_register(a, b)		(0)
1294 #define blk_integrity_unregister(a)		do { } while (0)
1295 #define blk_queue_max_integrity_segments(a, b)	do { } while (0)
1296 #define queue_max_integrity_segments(a)		(0)
1297 #define blk_integrity_merge_rq(a, b, c)		(0)
1298 #define blk_integrity_merge_bio(a, b, c)	(0)
1299 #define blk_integrity_is_initialized(a)		(0)
1300 
1301 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1302 
1303 struct block_device_operations {
1304 	int (*open) (struct block_device *, fmode_t);
1305 	int (*release) (struct gendisk *, fmode_t);
1306 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1307 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1308 	int (*direct_access) (struct block_device *, sector_t,
1309 						void **, unsigned long *);
1310 	unsigned int (*check_events) (struct gendisk *disk,
1311 				      unsigned int clearing);
1312 	/* ->media_changed() is DEPRECATED, use ->check_events() instead */
1313 	int (*media_changed) (struct gendisk *);
1314 	void (*unlock_native_capacity) (struct gendisk *);
1315 	int (*revalidate_disk) (struct gendisk *);
1316 	int (*getgeo)(struct block_device *, struct hd_geometry *);
1317 	/* this callback is with swap_lock and sometimes page table lock held */
1318 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1319 	struct module *owner;
1320 };
1321 
1322 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1323 				 unsigned long);
1324 #else /* CONFIG_BLOCK */
1325 /*
1326  * stubs for when the block layer is configured out
1327  */
1328 #define buffer_heads_over_limit 0
1329 
1330 static inline long nr_blockdev_pages(void)
1331 {
1332 	return 0;
1333 }
1334 
1335 struct blk_plug {
1336 };
1337 
1338 static inline void blk_start_plug(struct blk_plug *plug)
1339 {
1340 }
1341 
1342 static inline void blk_finish_plug(struct blk_plug *plug)
1343 {
1344 }
1345 
1346 static inline void blk_flush_plug(struct task_struct *task)
1347 {
1348 }
1349 
1350 static inline void blk_schedule_flush_plug(struct task_struct *task)
1351 {
1352 }
1353 
1354 
1355 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1356 {
1357 	return false;
1358 }
1359 
1360 #endif /* CONFIG_BLOCK */
1361 
1362 #endif
1363