xref: /linux-6.15/include/linux/blkdev.h (revision 078073a3)
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 struct bsg_job;
34 
35 #define BLKDEV_MIN_RQ	4
36 #define BLKDEV_MAX_RQ	128	/* Default maximum */
37 
38 struct request;
39 typedef void (rq_end_io_fn)(struct request *, int);
40 
41 struct request_list {
42 	/*
43 	 * count[], starved[], and wait[] are indexed by
44 	 * BLK_RW_SYNC/BLK_RW_ASYNC
45 	 */
46 	int count[2];
47 	int starved[2];
48 	int elvpriv;
49 	mempool_t *rq_pool;
50 	wait_queue_head_t wait[2];
51 };
52 
53 /*
54  * request command types
55  */
56 enum rq_cmd_type_bits {
57 	REQ_TYPE_FS		= 1,	/* fs request */
58 	REQ_TYPE_BLOCK_PC,		/* scsi command */
59 	REQ_TYPE_SENSE,			/* sense request */
60 	REQ_TYPE_PM_SUSPEND,		/* suspend request */
61 	REQ_TYPE_PM_RESUME,		/* resume request */
62 	REQ_TYPE_PM_SHUTDOWN,		/* shutdown request */
63 	REQ_TYPE_SPECIAL,		/* driver defined type */
64 	/*
65 	 * for ATA/ATAPI devices. this really doesn't belong here, ide should
66 	 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
67 	 * private REQ_LB opcodes to differentiate what type of request this is
68 	 */
69 	REQ_TYPE_ATA_TASKFILE,
70 	REQ_TYPE_ATA_PC,
71 };
72 
73 #define BLK_MAX_CDB	16
74 
75 /*
76  * try to put the fields that are referenced together in the same cacheline.
77  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
78  * as well!
79  */
80 struct request {
81 	struct list_head queuelist;
82 	struct call_single_data csd;
83 
84 	struct request_queue *q;
85 
86 	unsigned int cmd_flags;
87 	enum rq_cmd_type_bits cmd_type;
88 	unsigned long atomic_flags;
89 
90 	int cpu;
91 
92 	/* the following two fields are internal, NEVER access directly */
93 	unsigned int __data_len;	/* total data len */
94 	sector_t __sector;		/* sector cursor */
95 
96 	struct bio *bio;
97 	struct bio *biotail;
98 
99 	struct hlist_node hash;	/* merge hash */
100 	/*
101 	 * The rb_node is only used inside the io scheduler, requests
102 	 * are pruned when moved to the dispatch queue. So let the
103 	 * completion_data share space with the rb_node.
104 	 */
105 	union {
106 		struct rb_node rb_node;	/* sort/lookup */
107 		void *completion_data;
108 	};
109 
110 	/*
111 	 * Three pointers are available for the IO schedulers, if they need
112 	 * more they have to dynamically allocate it.  Flush requests are
113 	 * never put on the IO scheduler. So let the flush fields share
114 	 * space with the three elevator_private pointers.
115 	 */
116 	union {
117 		void *elevator_private[3];
118 		struct {
119 			unsigned int		seq;
120 			struct list_head	list;
121 			rq_end_io_fn		*saved_end_io;
122 		} flush;
123 	};
124 
125 	struct gendisk *rq_disk;
126 	struct hd_struct *part;
127 	unsigned long start_time;
128 #ifdef CONFIG_BLK_CGROUP
129 	unsigned long long start_time_ns;
130 	unsigned long long io_start_time_ns;    /* when passed to hardware */
131 #endif
132 	/* Number of scatter-gather DMA addr+len pairs after
133 	 * physical address coalescing is performed.
134 	 */
135 	unsigned short nr_phys_segments;
136 #if defined(CONFIG_BLK_DEV_INTEGRITY)
137 	unsigned short nr_integrity_segments;
138 #endif
139 
140 	unsigned short ioprio;
141 
142 	int ref_count;
143 
144 	void *special;		/* opaque pointer available for LLD use */
145 	char *buffer;		/* kaddr of the current segment if available */
146 
147 	int tag;
148 	int errors;
149 
150 	/*
151 	 * when request is used as a packet command carrier
152 	 */
153 	unsigned char __cmd[BLK_MAX_CDB];
154 	unsigned char *cmd;
155 	unsigned short cmd_len;
156 
157 	unsigned int extra_len;	/* length of alignment and padding */
158 	unsigned int sense_len;
159 	unsigned int resid_len;	/* residual count */
160 	void *sense;
161 
162 	unsigned long deadline;
163 	struct list_head timeout_list;
164 	unsigned int timeout;
165 	int retries;
166 
167 	/*
168 	 * completion callback.
169 	 */
170 	rq_end_io_fn *end_io;
171 	void *end_io_data;
172 
173 	/* for bidi */
174 	struct request *next_rq;
175 };
176 
177 static inline unsigned short req_get_ioprio(struct request *req)
178 {
179 	return req->ioprio;
180 }
181 
182 /*
183  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
184  * requests. Some step values could eventually be made generic.
185  */
186 struct request_pm_state
187 {
188 	/* PM state machine step value, currently driver specific */
189 	int	pm_step;
190 	/* requested PM state value (S1, S2, S3, S4, ...) */
191 	u32	pm_state;
192 	void*	data;		/* for driver use */
193 };
194 
195 #include <linux/elevator.h>
196 
197 typedef void (request_fn_proc) (struct request_queue *q);
198 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
199 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
200 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
201 
202 struct bio_vec;
203 struct bvec_merge_data {
204 	struct block_device *bi_bdev;
205 	sector_t bi_sector;
206 	unsigned bi_size;
207 	unsigned long bi_rw;
208 };
209 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
210 			     struct bio_vec *);
211 typedef void (softirq_done_fn)(struct request *);
212 typedef int (dma_drain_needed_fn)(struct request *);
213 typedef int (lld_busy_fn) (struct request_queue *q);
214 typedef int (bsg_job_fn) (struct bsg_job *);
215 
216 enum blk_eh_timer_return {
217 	BLK_EH_NOT_HANDLED,
218 	BLK_EH_HANDLED,
219 	BLK_EH_RESET_TIMER,
220 };
221 
222 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
223 
224 enum blk_queue_state {
225 	Queue_down,
226 	Queue_up,
227 };
228 
229 struct blk_queue_tag {
230 	struct request **tag_index;	/* map of busy tags */
231 	unsigned long *tag_map;		/* bit map of free/busy tags */
232 	int busy;			/* current depth */
233 	int max_depth;			/* what we will send to device */
234 	int real_max_depth;		/* what the array can hold */
235 	atomic_t refcnt;		/* map can be shared */
236 };
237 
238 #define BLK_SCSI_MAX_CMDS	(256)
239 #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
240 
241 struct queue_limits {
242 	unsigned long		bounce_pfn;
243 	unsigned long		seg_boundary_mask;
244 
245 	unsigned int		max_hw_sectors;
246 	unsigned int		max_sectors;
247 	unsigned int		max_segment_size;
248 	unsigned int		physical_block_size;
249 	unsigned int		alignment_offset;
250 	unsigned int		io_min;
251 	unsigned int		io_opt;
252 	unsigned int		max_discard_sectors;
253 	unsigned int		discard_granularity;
254 	unsigned int		discard_alignment;
255 
256 	unsigned short		logical_block_size;
257 	unsigned short		max_segments;
258 	unsigned short		max_integrity_segments;
259 
260 	unsigned char		misaligned;
261 	unsigned char		discard_misaligned;
262 	unsigned char		cluster;
263 	unsigned char		discard_zeroes_data;
264 };
265 
266 struct request_queue {
267 	/*
268 	 * Together with queue_head for cacheline sharing
269 	 */
270 	struct list_head	queue_head;
271 	struct request		*last_merge;
272 	struct elevator_queue	*elevator;
273 
274 	/*
275 	 * the queue request freelist, one for reads and one for writes
276 	 */
277 	struct request_list	rq;
278 
279 	request_fn_proc		*request_fn;
280 	make_request_fn		*make_request_fn;
281 	prep_rq_fn		*prep_rq_fn;
282 	unprep_rq_fn		*unprep_rq_fn;
283 	merge_bvec_fn		*merge_bvec_fn;
284 	softirq_done_fn		*softirq_done_fn;
285 	rq_timed_out_fn		*rq_timed_out_fn;
286 	dma_drain_needed_fn	*dma_drain_needed;
287 	lld_busy_fn		*lld_busy_fn;
288 
289 	/*
290 	 * Dispatch queue sorting
291 	 */
292 	sector_t		end_sector;
293 	struct request		*boundary_rq;
294 
295 	/*
296 	 * Delayed queue handling
297 	 */
298 	struct delayed_work	delay_work;
299 
300 	struct backing_dev_info	backing_dev_info;
301 
302 	/*
303 	 * The queue owner gets to use this for whatever they like.
304 	 * ll_rw_blk doesn't touch it.
305 	 */
306 	void			*queuedata;
307 
308 	/*
309 	 * various queue flags, see QUEUE_* below
310 	 */
311 	unsigned long		queue_flags;
312 
313 	/*
314 	 * queue needs bounce pages for pages above this limit
315 	 */
316 	gfp_t			bounce_gfp;
317 
318 	/*
319 	 * protects queue structures from reentrancy. ->__queue_lock should
320 	 * _never_ be used directly, it is queue private. always use
321 	 * ->queue_lock.
322 	 */
323 	spinlock_t		__queue_lock;
324 	spinlock_t		*queue_lock;
325 
326 	/*
327 	 * queue kobject
328 	 */
329 	struct kobject kobj;
330 
331 	/*
332 	 * queue settings
333 	 */
334 	unsigned long		nr_requests;	/* Max # of requests */
335 	unsigned int		nr_congestion_on;
336 	unsigned int		nr_congestion_off;
337 	unsigned int		nr_batching;
338 
339 	unsigned int		dma_drain_size;
340 	void			*dma_drain_buffer;
341 	unsigned int		dma_pad_mask;
342 	unsigned int		dma_alignment;
343 
344 	struct blk_queue_tag	*queue_tags;
345 	struct list_head	tag_busy_list;
346 
347 	unsigned int		nr_sorted;
348 	unsigned int		in_flight[2];
349 
350 	unsigned int		rq_timeout;
351 	struct timer_list	timeout;
352 	struct list_head	timeout_list;
353 
354 	struct queue_limits	limits;
355 
356 	/*
357 	 * sg stuff
358 	 */
359 	unsigned int		sg_timeout;
360 	unsigned int		sg_reserved_size;
361 	int			node;
362 #ifdef CONFIG_BLK_DEV_IO_TRACE
363 	struct blk_trace	*blk_trace;
364 #endif
365 	/*
366 	 * for flush operations
367 	 */
368 	unsigned int		flush_flags;
369 	unsigned int		flush_not_queueable:1;
370 	unsigned int		flush_queue_delayed:1;
371 	unsigned int		flush_pending_idx:1;
372 	unsigned int		flush_running_idx:1;
373 	unsigned long		flush_pending_since;
374 	struct list_head	flush_queue[2];
375 	struct list_head	flush_data_in_flight;
376 	struct request		flush_rq;
377 
378 	struct mutex		sysfs_lock;
379 
380 #if defined(CONFIG_BLK_DEV_BSG)
381 	bsg_job_fn		*bsg_job_fn;
382 	int			bsg_job_size;
383 	struct bsg_class_device bsg_dev;
384 #endif
385 
386 #ifdef CONFIG_BLK_DEV_THROTTLING
387 	/* Throttle data */
388 	struct throtl_data *td;
389 #endif
390 };
391 
392 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
393 #define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
394 #define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
395 #define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
396 #define QUEUE_FLAG_DEAD		5	/* queue being torn down */
397 #define QUEUE_FLAG_ELVSWITCH	6	/* don't use elevator, just do FIFO */
398 #define QUEUE_FLAG_BIDI		7	/* queue supports bidi requests */
399 #define QUEUE_FLAG_NOMERGES     8	/* disable merge attempts */
400 #define QUEUE_FLAG_SAME_COMP	9	/* complete on same CPU-group */
401 #define QUEUE_FLAG_FAIL_IO     10	/* fake timeout */
402 #define QUEUE_FLAG_STACKABLE   11	/* supports request stacking */
403 #define QUEUE_FLAG_NONROT      12	/* non-rotational device (SSD) */
404 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
405 #define QUEUE_FLAG_IO_STAT     13	/* do IO stats */
406 #define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
407 #define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
408 #define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
409 #define QUEUE_FLAG_SECDISCARD  17	/* supports SECDISCARD */
410 #define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
411 
412 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
413 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
414 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
415 				 (1 << QUEUE_FLAG_ADD_RANDOM))
416 
417 static inline int queue_is_locked(struct request_queue *q)
418 {
419 #ifdef CONFIG_SMP
420 	spinlock_t *lock = q->queue_lock;
421 	return lock && spin_is_locked(lock);
422 #else
423 	return 1;
424 #endif
425 }
426 
427 static inline void queue_flag_set_unlocked(unsigned int flag,
428 					   struct request_queue *q)
429 {
430 	__set_bit(flag, &q->queue_flags);
431 }
432 
433 static inline int queue_flag_test_and_clear(unsigned int flag,
434 					    struct request_queue *q)
435 {
436 	WARN_ON_ONCE(!queue_is_locked(q));
437 
438 	if (test_bit(flag, &q->queue_flags)) {
439 		__clear_bit(flag, &q->queue_flags);
440 		return 1;
441 	}
442 
443 	return 0;
444 }
445 
446 static inline int queue_flag_test_and_set(unsigned int flag,
447 					  struct request_queue *q)
448 {
449 	WARN_ON_ONCE(!queue_is_locked(q));
450 
451 	if (!test_bit(flag, &q->queue_flags)) {
452 		__set_bit(flag, &q->queue_flags);
453 		return 0;
454 	}
455 
456 	return 1;
457 }
458 
459 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
460 {
461 	WARN_ON_ONCE(!queue_is_locked(q));
462 	__set_bit(flag, &q->queue_flags);
463 }
464 
465 static inline void queue_flag_clear_unlocked(unsigned int flag,
466 					     struct request_queue *q)
467 {
468 	__clear_bit(flag, &q->queue_flags);
469 }
470 
471 static inline int queue_in_flight(struct request_queue *q)
472 {
473 	return q->in_flight[0] + q->in_flight[1];
474 }
475 
476 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
477 {
478 	WARN_ON_ONCE(!queue_is_locked(q));
479 	__clear_bit(flag, &q->queue_flags);
480 }
481 
482 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
483 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
484 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
485 #define blk_queue_noxmerges(q)	\
486 	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
487 #define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
488 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
489 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
490 #define blk_queue_stackable(q)	\
491 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
492 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
493 #define blk_queue_secdiscard(q)	(blk_queue_discard(q) && \
494 	test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
495 
496 #define blk_noretry_request(rq) \
497 	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
498 			     REQ_FAILFAST_DRIVER))
499 
500 #define blk_account_rq(rq) \
501 	(((rq)->cmd_flags & REQ_STARTED) && \
502 	 ((rq)->cmd_type == REQ_TYPE_FS || \
503 	  ((rq)->cmd_flags & REQ_DISCARD)))
504 
505 #define blk_pm_request(rq)	\
506 	((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
507 	 (rq)->cmd_type == REQ_TYPE_PM_RESUME)
508 
509 #define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
510 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
511 /* rq->queuelist of dequeued request must be list_empty() */
512 #define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
513 
514 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
515 
516 #define rq_data_dir(rq)		((rq)->cmd_flags & 1)
517 
518 static inline unsigned int blk_queue_cluster(struct request_queue *q)
519 {
520 	return q->limits.cluster;
521 }
522 
523 /*
524  * We regard a request as sync, if either a read or a sync write
525  */
526 static inline bool rw_is_sync(unsigned int rw_flags)
527 {
528 	return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
529 }
530 
531 static inline bool rq_is_sync(struct request *rq)
532 {
533 	return rw_is_sync(rq->cmd_flags);
534 }
535 
536 static inline int blk_queue_full(struct request_queue *q, int sync)
537 {
538 	if (sync)
539 		return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
540 	return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
541 }
542 
543 static inline void blk_set_queue_full(struct request_queue *q, int sync)
544 {
545 	if (sync)
546 		queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
547 	else
548 		queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
549 }
550 
551 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
552 {
553 	if (sync)
554 		queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
555 	else
556 		queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
557 }
558 
559 
560 /*
561  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
562  * it already be started by driver.
563  */
564 #define RQ_NOMERGE_FLAGS	\
565 	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
566 #define rq_mergeable(rq)	\
567 	(!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
568 	 (((rq)->cmd_flags & REQ_DISCARD) || \
569 	  (rq)->cmd_type == REQ_TYPE_FS))
570 
571 /*
572  * q->prep_rq_fn return values
573  */
574 #define BLKPREP_OK		0	/* serve it */
575 #define BLKPREP_KILL		1	/* fatal error, kill */
576 #define BLKPREP_DEFER		2	/* leave on queue */
577 
578 extern unsigned long blk_max_low_pfn, blk_max_pfn;
579 
580 /*
581  * standard bounce addresses:
582  *
583  * BLK_BOUNCE_HIGH	: bounce all highmem pages
584  * BLK_BOUNCE_ANY	: don't bounce anything
585  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
586  */
587 
588 #if BITS_PER_LONG == 32
589 #define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
590 #else
591 #define BLK_BOUNCE_HIGH		-1ULL
592 #endif
593 #define BLK_BOUNCE_ANY		(-1ULL)
594 #define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
595 
596 /*
597  * default timeout for SG_IO if none specified
598  */
599 #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
600 #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
601 
602 #ifdef CONFIG_BOUNCE
603 extern int init_emergency_isa_pool(void);
604 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
605 #else
606 static inline int init_emergency_isa_pool(void)
607 {
608 	return 0;
609 }
610 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
611 {
612 }
613 #endif /* CONFIG_MMU */
614 
615 struct rq_map_data {
616 	struct page **pages;
617 	int page_order;
618 	int nr_entries;
619 	unsigned long offset;
620 	int null_mapped;
621 	int from_user;
622 };
623 
624 struct req_iterator {
625 	int i;
626 	struct bio *bio;
627 };
628 
629 /* This should not be used directly - use rq_for_each_segment */
630 #define for_each_bio(_bio)		\
631 	for (; _bio; _bio = _bio->bi_next)
632 #define __rq_for_each_bio(_bio, rq)	\
633 	if ((rq->bio))			\
634 		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
635 
636 #define rq_for_each_segment(bvl, _rq, _iter)			\
637 	__rq_for_each_bio(_iter.bio, _rq)			\
638 		bio_for_each_segment(bvl, _iter.bio, _iter.i)
639 
640 #define rq_iter_last(rq, _iter)					\
641 		(_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
642 
643 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
644 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
645 #endif
646 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
647 extern void rq_flush_dcache_pages(struct request *rq);
648 #else
649 static inline void rq_flush_dcache_pages(struct request *rq)
650 {
651 }
652 #endif
653 
654 extern int blk_register_queue(struct gendisk *disk);
655 extern void blk_unregister_queue(struct gendisk *disk);
656 extern void generic_make_request(struct bio *bio);
657 extern void blk_rq_init(struct request_queue *q, struct request *rq);
658 extern void blk_put_request(struct request *);
659 extern void __blk_put_request(struct request_queue *, struct request *);
660 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
661 extern struct request *blk_make_request(struct request_queue *, struct bio *,
662 					gfp_t);
663 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
664 extern void blk_requeue_request(struct request_queue *, struct request *);
665 extern void blk_add_request_payload(struct request *rq, struct page *page,
666 		unsigned int len);
667 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
668 extern int blk_lld_busy(struct request_queue *q);
669 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
670 			     struct bio_set *bs, gfp_t gfp_mask,
671 			     int (*bio_ctr)(struct bio *, struct bio *, void *),
672 			     void *data);
673 extern void blk_rq_unprep_clone(struct request *rq);
674 extern int blk_insert_cloned_request(struct request_queue *q,
675 				     struct request *rq);
676 extern void blk_delay_queue(struct request_queue *, unsigned long);
677 extern void blk_recount_segments(struct request_queue *, struct bio *);
678 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
679 			  unsigned int, void __user *);
680 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
681 			 struct scsi_ioctl_command __user *);
682 
683 /*
684  * A queue has just exitted congestion.  Note this in the global counter of
685  * congested queues, and wake up anyone who was waiting for requests to be
686  * put back.
687  */
688 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
689 {
690 	clear_bdi_congested(&q->backing_dev_info, sync);
691 }
692 
693 /*
694  * A queue has just entered congestion.  Flag that in the queue's VM-visible
695  * state flags and increment the global gounter of congested queues.
696  */
697 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
698 {
699 	set_bdi_congested(&q->backing_dev_info, sync);
700 }
701 
702 extern void blk_start_queue(struct request_queue *q);
703 extern void blk_stop_queue(struct request_queue *q);
704 extern void blk_sync_queue(struct request_queue *q);
705 extern void __blk_stop_queue(struct request_queue *q);
706 extern void __blk_run_queue(struct request_queue *q);
707 extern void blk_run_queue(struct request_queue *);
708 extern void blk_run_queue_async(struct request_queue *q);
709 extern int blk_rq_map_user(struct request_queue *, struct request *,
710 			   struct rq_map_data *, void __user *, unsigned long,
711 			   gfp_t);
712 extern int blk_rq_unmap_user(struct bio *);
713 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
714 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
715 			       struct rq_map_data *, struct sg_iovec *, int,
716 			       unsigned int, gfp_t);
717 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
718 			  struct request *, int);
719 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
720 				  struct request *, int, rq_end_io_fn *);
721 
722 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
723 {
724 	return bdev->bd_disk->queue;
725 }
726 
727 /*
728  * blk_rq_pos()			: the current sector
729  * blk_rq_bytes()		: bytes left in the entire request
730  * blk_rq_cur_bytes()		: bytes left in the current segment
731  * blk_rq_err_bytes()		: bytes left till the next error boundary
732  * blk_rq_sectors()		: sectors left in the entire request
733  * blk_rq_cur_sectors()		: sectors left in the current segment
734  */
735 static inline sector_t blk_rq_pos(const struct request *rq)
736 {
737 	return rq->__sector;
738 }
739 
740 static inline unsigned int blk_rq_bytes(const struct request *rq)
741 {
742 	return rq->__data_len;
743 }
744 
745 static inline int blk_rq_cur_bytes(const struct request *rq)
746 {
747 	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
748 }
749 
750 extern unsigned int blk_rq_err_bytes(const struct request *rq);
751 
752 static inline unsigned int blk_rq_sectors(const struct request *rq)
753 {
754 	return blk_rq_bytes(rq) >> 9;
755 }
756 
757 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
758 {
759 	return blk_rq_cur_bytes(rq) >> 9;
760 }
761 
762 /*
763  * Request issue related functions.
764  */
765 extern struct request *blk_peek_request(struct request_queue *q);
766 extern void blk_start_request(struct request *rq);
767 extern struct request *blk_fetch_request(struct request_queue *q);
768 
769 /*
770  * Request completion related functions.
771  *
772  * blk_update_request() completes given number of bytes and updates
773  * the request without completing it.
774  *
775  * blk_end_request() and friends.  __blk_end_request() must be called
776  * with the request queue spinlock acquired.
777  *
778  * Several drivers define their own end_request and call
779  * blk_end_request() for parts of the original function.
780  * This prevents code duplication in drivers.
781  */
782 extern bool blk_update_request(struct request *rq, int error,
783 			       unsigned int nr_bytes);
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 extern bool __blk_end_request(struct request *rq, int error,
790 			      unsigned int nr_bytes);
791 extern void __blk_end_request_all(struct request *rq, int error);
792 extern bool __blk_end_request_cur(struct request *rq, int error);
793 extern bool __blk_end_request_err(struct request *rq, int error);
794 
795 extern void blk_complete_request(struct request *);
796 extern void __blk_complete_request(struct request *);
797 extern void blk_abort_request(struct request *);
798 extern void blk_abort_queue(struct request_queue *);
799 extern void blk_unprep_request(struct request *);
800 
801 /*
802  * Access functions for manipulating queue properties
803  */
804 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
805 					spinlock_t *lock, int node_id);
806 extern struct request_queue *blk_init_allocated_queue_node(struct request_queue *,
807 							   request_fn_proc *,
808 							   spinlock_t *, int node_id);
809 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
810 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
811 						      request_fn_proc *, spinlock_t *);
812 extern void blk_cleanup_queue(struct request_queue *);
813 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
814 extern void blk_queue_bounce_limit(struct request_queue *, u64);
815 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
816 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
817 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
818 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
819 extern void blk_queue_max_discard_sectors(struct request_queue *q,
820 		unsigned int max_discard_sectors);
821 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
822 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
823 extern void blk_queue_alignment_offset(struct request_queue *q,
824 				       unsigned int alignment);
825 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
826 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
827 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
828 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
829 extern void blk_set_default_limits(struct queue_limits *lim);
830 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
831 			    sector_t offset);
832 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
833 			    sector_t offset);
834 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
835 			      sector_t offset);
836 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
837 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
838 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
839 extern int blk_queue_dma_drain(struct request_queue *q,
840 			       dma_drain_needed_fn *dma_drain_needed,
841 			       void *buf, unsigned int size);
842 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
843 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
844 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
845 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
846 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
847 extern void blk_queue_dma_alignment(struct request_queue *, int);
848 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
849 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
850 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
851 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
852 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
853 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
854 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
855 
856 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
857 extern void blk_dump_rq_flags(struct request *, char *);
858 extern long nr_blockdev_pages(void);
859 
860 int blk_get_queue(struct request_queue *);
861 struct request_queue *blk_alloc_queue(gfp_t);
862 struct request_queue *blk_alloc_queue_node(gfp_t, int);
863 extern void blk_put_queue(struct request_queue *);
864 
865 /*
866  * Note: Code in between changing the blk_plug list/cb_list or element of such
867  * lists is preemptable, but such code can't do sleep (or be very careful),
868  * otherwise data is corrupted. For details, please check schedule() where
869  * blk_schedule_flush_plug() is called.
870  */
871 struct blk_plug {
872 	unsigned long magic;
873 	struct list_head list;
874 	struct list_head cb_list;
875 	unsigned int should_sort;
876 };
877 #define BLK_MAX_REQUEST_COUNT 16
878 
879 struct blk_plug_cb {
880 	struct list_head list;
881 	void (*callback)(struct blk_plug_cb *);
882 };
883 
884 extern void blk_start_plug(struct blk_plug *);
885 extern void blk_finish_plug(struct blk_plug *);
886 extern void blk_flush_plug_list(struct blk_plug *, bool);
887 
888 static inline void blk_flush_plug(struct task_struct *tsk)
889 {
890 	struct blk_plug *plug = tsk->plug;
891 
892 	if (plug)
893 		blk_flush_plug_list(plug, false);
894 }
895 
896 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
897 {
898 	struct blk_plug *plug = tsk->plug;
899 
900 	if (plug)
901 		blk_flush_plug_list(plug, true);
902 }
903 
904 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
905 {
906 	struct blk_plug *plug = tsk->plug;
907 
908 	return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
909 }
910 
911 /*
912  * tag stuff
913  */
914 #define blk_rq_tagged(rq)		((rq)->cmd_flags & REQ_QUEUED)
915 extern int blk_queue_start_tag(struct request_queue *, struct request *);
916 extern struct request *blk_queue_find_tag(struct request_queue *, int);
917 extern void blk_queue_end_tag(struct request_queue *, struct request *);
918 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
919 extern void blk_queue_free_tags(struct request_queue *);
920 extern int blk_queue_resize_tags(struct request_queue *, int);
921 extern void blk_queue_invalidate_tags(struct request_queue *);
922 extern struct blk_queue_tag *blk_init_tags(int);
923 extern void blk_free_tags(struct blk_queue_tag *);
924 
925 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
926 						int tag)
927 {
928 	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
929 		return NULL;
930 	return bqt->tag_index[tag];
931 }
932 
933 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
934 
935 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
936 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
937 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
938 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
939 			sector_t nr_sects, gfp_t gfp_mask);
940 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
941 		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
942 {
943 	return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
944 				    nr_blocks << (sb->s_blocksize_bits - 9),
945 				    gfp_mask, flags);
946 }
947 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
948 		sector_t nr_blocks, gfp_t gfp_mask)
949 {
950 	return blkdev_issue_zeroout(sb->s_bdev,
951 				    block << (sb->s_blocksize_bits - 9),
952 				    nr_blocks << (sb->s_blocksize_bits - 9),
953 				    gfp_mask);
954 }
955 
956 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
957 
958 enum blk_default_limits {
959 	BLK_MAX_SEGMENTS	= 128,
960 	BLK_SAFE_MAX_SECTORS	= 255,
961 	BLK_DEF_MAX_SECTORS	= 1024,
962 	BLK_MAX_SEGMENT_SIZE	= 65536,
963 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
964 };
965 
966 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
967 
968 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
969 {
970 	return q->limits.bounce_pfn;
971 }
972 
973 static inline unsigned long queue_segment_boundary(struct request_queue *q)
974 {
975 	return q->limits.seg_boundary_mask;
976 }
977 
978 static inline unsigned int queue_max_sectors(struct request_queue *q)
979 {
980 	return q->limits.max_sectors;
981 }
982 
983 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
984 {
985 	return q->limits.max_hw_sectors;
986 }
987 
988 static inline unsigned short queue_max_segments(struct request_queue *q)
989 {
990 	return q->limits.max_segments;
991 }
992 
993 static inline unsigned int queue_max_segment_size(struct request_queue *q)
994 {
995 	return q->limits.max_segment_size;
996 }
997 
998 static inline unsigned short queue_logical_block_size(struct request_queue *q)
999 {
1000 	int retval = 512;
1001 
1002 	if (q && q->limits.logical_block_size)
1003 		retval = q->limits.logical_block_size;
1004 
1005 	return retval;
1006 }
1007 
1008 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1009 {
1010 	return queue_logical_block_size(bdev_get_queue(bdev));
1011 }
1012 
1013 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1014 {
1015 	return q->limits.physical_block_size;
1016 }
1017 
1018 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1019 {
1020 	return queue_physical_block_size(bdev_get_queue(bdev));
1021 }
1022 
1023 static inline unsigned int queue_io_min(struct request_queue *q)
1024 {
1025 	return q->limits.io_min;
1026 }
1027 
1028 static inline int bdev_io_min(struct block_device *bdev)
1029 {
1030 	return queue_io_min(bdev_get_queue(bdev));
1031 }
1032 
1033 static inline unsigned int queue_io_opt(struct request_queue *q)
1034 {
1035 	return q->limits.io_opt;
1036 }
1037 
1038 static inline int bdev_io_opt(struct block_device *bdev)
1039 {
1040 	return queue_io_opt(bdev_get_queue(bdev));
1041 }
1042 
1043 static inline int queue_alignment_offset(struct request_queue *q)
1044 {
1045 	if (q->limits.misaligned)
1046 		return -1;
1047 
1048 	return q->limits.alignment_offset;
1049 }
1050 
1051 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1052 {
1053 	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1054 	unsigned int alignment = (sector << 9) & (granularity - 1);
1055 
1056 	return (granularity + lim->alignment_offset - alignment)
1057 		& (granularity - 1);
1058 }
1059 
1060 static inline int bdev_alignment_offset(struct block_device *bdev)
1061 {
1062 	struct request_queue *q = bdev_get_queue(bdev);
1063 
1064 	if (q->limits.misaligned)
1065 		return -1;
1066 
1067 	if (bdev != bdev->bd_contains)
1068 		return bdev->bd_part->alignment_offset;
1069 
1070 	return q->limits.alignment_offset;
1071 }
1072 
1073 static inline int queue_discard_alignment(struct request_queue *q)
1074 {
1075 	if (q->limits.discard_misaligned)
1076 		return -1;
1077 
1078 	return q->limits.discard_alignment;
1079 }
1080 
1081 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1082 {
1083 	unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1084 
1085 	if (!lim->max_discard_sectors)
1086 		return 0;
1087 
1088 	return (lim->discard_granularity + lim->discard_alignment - alignment)
1089 		& (lim->discard_granularity - 1);
1090 }
1091 
1092 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1093 {
1094 	if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1095 		return 1;
1096 
1097 	return 0;
1098 }
1099 
1100 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1101 {
1102 	return queue_discard_zeroes_data(bdev_get_queue(bdev));
1103 }
1104 
1105 static inline int queue_dma_alignment(struct request_queue *q)
1106 {
1107 	return q ? q->dma_alignment : 511;
1108 }
1109 
1110 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1111 				 unsigned int len)
1112 {
1113 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1114 	return !(addr & alignment) && !(len & alignment);
1115 }
1116 
1117 /* assumes size > 256 */
1118 static inline unsigned int blksize_bits(unsigned int size)
1119 {
1120 	unsigned int bits = 8;
1121 	do {
1122 		bits++;
1123 		size >>= 1;
1124 	} while (size > 256);
1125 	return bits;
1126 }
1127 
1128 static inline unsigned int block_size(struct block_device *bdev)
1129 {
1130 	return bdev->bd_block_size;
1131 }
1132 
1133 static inline bool queue_flush_queueable(struct request_queue *q)
1134 {
1135 	return !q->flush_not_queueable;
1136 }
1137 
1138 typedef struct {struct page *v;} Sector;
1139 
1140 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1141 
1142 static inline void put_dev_sector(Sector p)
1143 {
1144 	page_cache_release(p.v);
1145 }
1146 
1147 struct work_struct;
1148 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1149 
1150 #ifdef CONFIG_BLK_CGROUP
1151 /*
1152  * This should not be using sched_clock(). A real patch is in progress
1153  * to fix this up, until that is in place we need to disable preemption
1154  * around sched_clock() in this function and set_io_start_time_ns().
1155  */
1156 static inline void set_start_time_ns(struct request *req)
1157 {
1158 	preempt_disable();
1159 	req->start_time_ns = sched_clock();
1160 	preempt_enable();
1161 }
1162 
1163 static inline void set_io_start_time_ns(struct request *req)
1164 {
1165 	preempt_disable();
1166 	req->io_start_time_ns = sched_clock();
1167 	preempt_enable();
1168 }
1169 
1170 static inline uint64_t rq_start_time_ns(struct request *req)
1171 {
1172         return req->start_time_ns;
1173 }
1174 
1175 static inline uint64_t rq_io_start_time_ns(struct request *req)
1176 {
1177         return req->io_start_time_ns;
1178 }
1179 #else
1180 static inline void set_start_time_ns(struct request *req) {}
1181 static inline void set_io_start_time_ns(struct request *req) {}
1182 static inline uint64_t rq_start_time_ns(struct request *req)
1183 {
1184 	return 0;
1185 }
1186 static inline uint64_t rq_io_start_time_ns(struct request *req)
1187 {
1188 	return 0;
1189 }
1190 #endif
1191 
1192 #ifdef CONFIG_BLK_DEV_THROTTLING
1193 extern int blk_throtl_init(struct request_queue *q);
1194 extern void blk_throtl_exit(struct request_queue *q);
1195 extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
1196 #else /* CONFIG_BLK_DEV_THROTTLING */
1197 static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
1198 {
1199 	return 0;
1200 }
1201 
1202 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
1203 static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
1204 #endif /* CONFIG_BLK_DEV_THROTTLING */
1205 
1206 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1207 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1208 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1209 	MODULE_ALIAS("block-major-" __stringify(major) "-*")
1210 
1211 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1212 
1213 #define INTEGRITY_FLAG_READ	2	/* verify data integrity on read */
1214 #define INTEGRITY_FLAG_WRITE	4	/* generate data integrity on write */
1215 
1216 struct blk_integrity_exchg {
1217 	void			*prot_buf;
1218 	void			*data_buf;
1219 	sector_t		sector;
1220 	unsigned int		data_size;
1221 	unsigned short		sector_size;
1222 	const char		*disk_name;
1223 };
1224 
1225 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1226 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1227 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1228 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1229 
1230 struct blk_integrity {
1231 	integrity_gen_fn	*generate_fn;
1232 	integrity_vrfy_fn	*verify_fn;
1233 	integrity_set_tag_fn	*set_tag_fn;
1234 	integrity_get_tag_fn	*get_tag_fn;
1235 
1236 	unsigned short		flags;
1237 	unsigned short		tuple_size;
1238 	unsigned short		sector_size;
1239 	unsigned short		tag_size;
1240 
1241 	const char		*name;
1242 
1243 	struct kobject		kobj;
1244 };
1245 
1246 extern bool blk_integrity_is_initialized(struct gendisk *);
1247 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1248 extern void blk_integrity_unregister(struct gendisk *);
1249 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1250 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1251 				   struct scatterlist *);
1252 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1253 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1254 				  struct request *);
1255 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1256 				   struct bio *);
1257 
1258 static inline
1259 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1260 {
1261 	return bdev->bd_disk->integrity;
1262 }
1263 
1264 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1265 {
1266 	return disk->integrity;
1267 }
1268 
1269 static inline int blk_integrity_rq(struct request *rq)
1270 {
1271 	if (rq->bio == NULL)
1272 		return 0;
1273 
1274 	return bio_integrity(rq->bio);
1275 }
1276 
1277 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1278 						    unsigned int segs)
1279 {
1280 	q->limits.max_integrity_segments = segs;
1281 }
1282 
1283 static inline unsigned short
1284 queue_max_integrity_segments(struct request_queue *q)
1285 {
1286 	return q->limits.max_integrity_segments;
1287 }
1288 
1289 #else /* CONFIG_BLK_DEV_INTEGRITY */
1290 
1291 #define blk_integrity_rq(rq)			(0)
1292 #define blk_rq_count_integrity_sg(a, b)		(0)
1293 #define blk_rq_map_integrity_sg(a, b, c)	(0)
1294 #define bdev_get_integrity(a)			(0)
1295 #define blk_get_integrity(a)			(0)
1296 #define blk_integrity_compare(a, b)		(0)
1297 #define blk_integrity_register(a, b)		(0)
1298 #define blk_integrity_unregister(a)		do { } while (0)
1299 #define blk_queue_max_integrity_segments(a, b)	do { } while (0)
1300 #define queue_max_integrity_segments(a)		(0)
1301 #define blk_integrity_merge_rq(a, b, c)		(0)
1302 #define blk_integrity_merge_bio(a, b, c)	(0)
1303 #define blk_integrity_is_initialized(a)		(0)
1304 
1305 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1306 
1307 struct block_device_operations {
1308 	int (*open) (struct block_device *, fmode_t);
1309 	int (*release) (struct gendisk *, fmode_t);
1310 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1311 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1312 	int (*direct_access) (struct block_device *, sector_t,
1313 						void **, unsigned long *);
1314 	unsigned int (*check_events) (struct gendisk *disk,
1315 				      unsigned int clearing);
1316 	/* ->media_changed() is DEPRECATED, use ->check_events() instead */
1317 	int (*media_changed) (struct gendisk *);
1318 	void (*unlock_native_capacity) (struct gendisk *);
1319 	int (*revalidate_disk) (struct gendisk *);
1320 	int (*getgeo)(struct block_device *, struct hd_geometry *);
1321 	/* this callback is with swap_lock and sometimes page table lock held */
1322 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1323 	struct module *owner;
1324 };
1325 
1326 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1327 				 unsigned long);
1328 #else /* CONFIG_BLOCK */
1329 /*
1330  * stubs for when the block layer is configured out
1331  */
1332 #define buffer_heads_over_limit 0
1333 
1334 static inline long nr_blockdev_pages(void)
1335 {
1336 	return 0;
1337 }
1338 
1339 struct blk_plug {
1340 };
1341 
1342 static inline void blk_start_plug(struct blk_plug *plug)
1343 {
1344 }
1345 
1346 static inline void blk_finish_plug(struct blk_plug *plug)
1347 {
1348 }
1349 
1350 static inline void blk_flush_plug(struct task_struct *task)
1351 {
1352 }
1353 
1354 static inline void blk_schedule_flush_plug(struct task_struct *task)
1355 {
1356 }
1357 
1358 
1359 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1360 {
1361 	return false;
1362 }
1363 
1364 #endif /* CONFIG_BLOCK */
1365 
1366 #endif
1367