xref: /linux-6.15/include/linux/blkdev.h (revision 54ebbfb1)
1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
3 
4 #include <linux/sched.h>
5 #include <linux/sched/clock.h>
6 
7 #ifdef CONFIG_BLOCK
8 
9 #include <linux/major.h>
10 #include <linux/genhd.h>
11 #include <linux/list.h>
12 #include <linux/llist.h>
13 #include <linux/timer.h>
14 #include <linux/workqueue.h>
15 #include <linux/pagemap.h>
16 #include <linux/backing-dev-defs.h>
17 #include <linux/wait.h>
18 #include <linux/mempool.h>
19 #include <linux/pfn.h>
20 #include <linux/bio.h>
21 #include <linux/stringify.h>
22 #include <linux/gfp.h>
23 #include <linux/bsg.h>
24 #include <linux/smp.h>
25 #include <linux/rcupdate.h>
26 #include <linux/percpu-refcount.h>
27 #include <linux/scatterlist.h>
28 #include <linux/blkzoned.h>
29 
30 struct module;
31 struct scsi_ioctl_command;
32 
33 struct request_queue;
34 struct elevator_queue;
35 struct blk_trace;
36 struct request;
37 struct sg_io_hdr;
38 struct bsg_job;
39 struct blkcg_gq;
40 struct blk_flush_queue;
41 struct pr_ops;
42 struct rq_wb;
43 struct blk_queue_stats;
44 struct blk_stat_callback;
45 
46 #define BLKDEV_MIN_RQ	4
47 #define BLKDEV_MAX_RQ	128	/* Default maximum */
48 
49 /* Must be consisitent with blk_mq_poll_stats_bkt() */
50 #define BLK_MQ_POLL_STATS_BKTS 16
51 
52 /*
53  * Maximum number of blkcg policies allowed to be registered concurrently.
54  * Defined here to simplify include dependency.
55  */
56 #define BLKCG_MAX_POLS		3
57 
58 typedef void (rq_end_io_fn)(struct request *, int);
59 
60 #define BLK_RL_SYNCFULL		(1U << 0)
61 #define BLK_RL_ASYNCFULL	(1U << 1)
62 
63 struct request_list {
64 	struct request_queue	*q;	/* the queue this rl belongs to */
65 #ifdef CONFIG_BLK_CGROUP
66 	struct blkcg_gq		*blkg;	/* blkg this request pool belongs to */
67 #endif
68 	/*
69 	 * count[], starved[], and wait[] are indexed by
70 	 * BLK_RW_SYNC/BLK_RW_ASYNC
71 	 */
72 	int			count[2];
73 	int			starved[2];
74 	mempool_t		*rq_pool;
75 	wait_queue_head_t	wait[2];
76 	unsigned int		flags;
77 };
78 
79 /*
80  * request flags */
81 typedef __u32 __bitwise req_flags_t;
82 
83 /* elevator knows about this request */
84 #define RQF_SORTED		((__force req_flags_t)(1 << 0))
85 /* drive already may have started this one */
86 #define RQF_STARTED		((__force req_flags_t)(1 << 1))
87 /* uses tagged queueing */
88 #define RQF_QUEUED		((__force req_flags_t)(1 << 2))
89 /* may not be passed by ioscheduler */
90 #define RQF_SOFTBARRIER		((__force req_flags_t)(1 << 3))
91 /* request for flush sequence */
92 #define RQF_FLUSH_SEQ		((__force req_flags_t)(1 << 4))
93 /* merge of different types, fail separately */
94 #define RQF_MIXED_MERGE		((__force req_flags_t)(1 << 5))
95 /* track inflight for MQ */
96 #define RQF_MQ_INFLIGHT		((__force req_flags_t)(1 << 6))
97 /* don't call prep for this one */
98 #define RQF_DONTPREP		((__force req_flags_t)(1 << 7))
99 /* set for "ide_preempt" requests and also for requests for which the SCSI
100    "quiesce" state must be ignored. */
101 #define RQF_PREEMPT		((__force req_flags_t)(1 << 8))
102 /* contains copies of user pages */
103 #define RQF_COPY_USER		((__force req_flags_t)(1 << 9))
104 /* vaguely specified driver internal error.  Ignored by the block layer */
105 #define RQF_FAILED		((__force req_flags_t)(1 << 10))
106 /* don't warn about errors */
107 #define RQF_QUIET		((__force req_flags_t)(1 << 11))
108 /* elevator private data attached */
109 #define RQF_ELVPRIV		((__force req_flags_t)(1 << 12))
110 /* account I/O stat */
111 #define RQF_IO_STAT		((__force req_flags_t)(1 << 13))
112 /* request came from our alloc pool */
113 #define RQF_ALLOCED		((__force req_flags_t)(1 << 14))
114 /* runtime pm request */
115 #define RQF_PM			((__force req_flags_t)(1 << 15))
116 /* on IO scheduler merge hash */
117 #define RQF_HASHED		((__force req_flags_t)(1 << 16))
118 /* IO stats tracking on */
119 #define RQF_STATS		((__force req_flags_t)(1 << 17))
120 /* Look at ->special_vec for the actual data payload instead of the
121    bio chain. */
122 #define RQF_SPECIAL_PAYLOAD	((__force req_flags_t)(1 << 18))
123 
124 /* flags that prevent us from merging requests: */
125 #define RQF_NOMERGE_FLAGS \
126 	(RQF_STARTED | RQF_SOFTBARRIER | RQF_FLUSH_SEQ | RQF_SPECIAL_PAYLOAD)
127 
128 /*
129  * Try to put the fields that are referenced together in the same cacheline.
130  *
131  * If you modify this structure, make sure to update blk_rq_init() and
132  * especially blk_mq_rq_ctx_init() to take care of the added fields.
133  */
134 struct request {
135 	struct list_head queuelist;
136 	union {
137 		struct call_single_data csd;
138 		u64 fifo_time;
139 	};
140 
141 	struct request_queue *q;
142 	struct blk_mq_ctx *mq_ctx;
143 
144 	int cpu;
145 	unsigned int cmd_flags;		/* op and common flags */
146 	req_flags_t rq_flags;
147 
148 	int internal_tag;
149 
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 	int tag;
155 	sector_t __sector;		/* sector cursor */
156 
157 	struct bio *bio;
158 	struct bio *biotail;
159 
160 	/*
161 	 * The hash is used inside the scheduler, and killed once the
162 	 * request reaches the dispatch list. The ipi_list is only used
163 	 * to queue the request for softirq completion, which is long
164 	 * after the request has been unhashed (and even removed from
165 	 * the dispatch list).
166 	 */
167 	union {
168 		struct hlist_node hash;	/* merge hash */
169 		struct list_head ipi_list;
170 	};
171 
172 	/*
173 	 * The rb_node is only used inside the io scheduler, requests
174 	 * are pruned when moved to the dispatch queue. So let the
175 	 * completion_data share space with the rb_node.
176 	 */
177 	union {
178 		struct rb_node rb_node;	/* sort/lookup */
179 		struct bio_vec special_vec;
180 		void *completion_data;
181 		int error_count; /* for legacy drivers, don't use */
182 	};
183 
184 	/*
185 	 * Three pointers are available for the IO schedulers, if they need
186 	 * more they have to dynamically allocate it.  Flush requests are
187 	 * never put on the IO scheduler. So let the flush fields share
188 	 * space with the elevator data.
189 	 */
190 	union {
191 		struct {
192 			struct io_cq		*icq;
193 			void			*priv[2];
194 		} elv;
195 
196 		struct {
197 			unsigned int		seq;
198 			struct list_head	list;
199 			rq_end_io_fn		*saved_end_io;
200 		} flush;
201 	};
202 
203 	struct gendisk *rq_disk;
204 	struct hd_struct *part;
205 	unsigned long start_time;
206 	struct blk_issue_stat issue_stat;
207 #ifdef CONFIG_BLK_CGROUP
208 	struct request_list *rl;		/* rl this rq is alloced from */
209 	unsigned long long start_time_ns;
210 	unsigned long long io_start_time_ns;    /* when passed to hardware */
211 #endif
212 	/* Number of scatter-gather DMA addr+len pairs after
213 	 * physical address coalescing is performed.
214 	 */
215 	unsigned short nr_phys_segments;
216 #if defined(CONFIG_BLK_DEV_INTEGRITY)
217 	unsigned short nr_integrity_segments;
218 #endif
219 
220 	unsigned short ioprio;
221 
222 	unsigned int timeout;
223 
224 	void *special;		/* opaque pointer available for LLD use */
225 
226 	unsigned int extra_len;	/* length of alignment and padding */
227 
228 	unsigned long deadline;
229 	struct list_head timeout_list;
230 
231 	/*
232 	 * completion callback.
233 	 */
234 	rq_end_io_fn *end_io;
235 	void *end_io_data;
236 
237 	/* for bidi */
238 	struct request *next_rq;
239 };
240 
241 static inline bool blk_rq_is_scsi(struct request *rq)
242 {
243 	return req_op(rq) == REQ_OP_SCSI_IN || req_op(rq) == REQ_OP_SCSI_OUT;
244 }
245 
246 static inline bool blk_rq_is_private(struct request *rq)
247 {
248 	return req_op(rq) == REQ_OP_DRV_IN || req_op(rq) == REQ_OP_DRV_OUT;
249 }
250 
251 static inline bool blk_rq_is_passthrough(struct request *rq)
252 {
253 	return blk_rq_is_scsi(rq) || blk_rq_is_private(rq);
254 }
255 
256 static inline unsigned short req_get_ioprio(struct request *req)
257 {
258 	return req->ioprio;
259 }
260 
261 #include <linux/elevator.h>
262 
263 struct blk_queue_ctx;
264 
265 typedef void (request_fn_proc) (struct request_queue *q);
266 typedef blk_qc_t (make_request_fn) (struct request_queue *q, struct bio *bio);
267 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
268 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
269 
270 struct bio_vec;
271 typedef void (softirq_done_fn)(struct request *);
272 typedef int (dma_drain_needed_fn)(struct request *);
273 typedef int (lld_busy_fn) (struct request_queue *q);
274 typedef int (bsg_job_fn) (struct bsg_job *);
275 typedef int (init_rq_fn)(struct request_queue *, struct request *, gfp_t);
276 typedef void (exit_rq_fn)(struct request_queue *, struct request *);
277 
278 enum blk_eh_timer_return {
279 	BLK_EH_NOT_HANDLED,
280 	BLK_EH_HANDLED,
281 	BLK_EH_RESET_TIMER,
282 };
283 
284 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
285 
286 enum blk_queue_state {
287 	Queue_down,
288 	Queue_up,
289 };
290 
291 struct blk_queue_tag {
292 	struct request **tag_index;	/* map of busy tags */
293 	unsigned long *tag_map;		/* bit map of free/busy tags */
294 	int max_depth;			/* what we will send to device */
295 	int real_max_depth;		/* what the array can hold */
296 	atomic_t refcnt;		/* map can be shared */
297 	int alloc_policy;		/* tag allocation policy */
298 	int next_tag;			/* next tag */
299 };
300 #define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */
301 #define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */
302 
303 #define BLK_SCSI_MAX_CMDS	(256)
304 #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
305 
306 /*
307  * Zoned block device models (zoned limit).
308  */
309 enum blk_zoned_model {
310 	BLK_ZONED_NONE,	/* Regular block device */
311 	BLK_ZONED_HA,	/* Host-aware zoned block device */
312 	BLK_ZONED_HM,	/* Host-managed zoned block device */
313 };
314 
315 struct queue_limits {
316 	unsigned long		bounce_pfn;
317 	unsigned long		seg_boundary_mask;
318 	unsigned long		virt_boundary_mask;
319 
320 	unsigned int		max_hw_sectors;
321 	unsigned int		max_dev_sectors;
322 	unsigned int		chunk_sectors;
323 	unsigned int		max_sectors;
324 	unsigned int		max_segment_size;
325 	unsigned int		physical_block_size;
326 	unsigned int		alignment_offset;
327 	unsigned int		io_min;
328 	unsigned int		io_opt;
329 	unsigned int		max_discard_sectors;
330 	unsigned int		max_hw_discard_sectors;
331 	unsigned int		max_write_same_sectors;
332 	unsigned int		max_write_zeroes_sectors;
333 	unsigned int		discard_granularity;
334 	unsigned int		discard_alignment;
335 
336 	unsigned short		logical_block_size;
337 	unsigned short		max_segments;
338 	unsigned short		max_integrity_segments;
339 	unsigned short		max_discard_segments;
340 
341 	unsigned char		misaligned;
342 	unsigned char		discard_misaligned;
343 	unsigned char		cluster;
344 	unsigned char		raid_partial_stripes_expensive;
345 	enum blk_zoned_model	zoned;
346 };
347 
348 #ifdef CONFIG_BLK_DEV_ZONED
349 
350 struct blk_zone_report_hdr {
351 	unsigned int	nr_zones;
352 	u8		padding[60];
353 };
354 
355 extern int blkdev_report_zones(struct block_device *bdev,
356 			       sector_t sector, struct blk_zone *zones,
357 			       unsigned int *nr_zones, gfp_t gfp_mask);
358 extern int blkdev_reset_zones(struct block_device *bdev, sector_t sectors,
359 			      sector_t nr_sectors, gfp_t gfp_mask);
360 
361 extern int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
362 				     unsigned int cmd, unsigned long arg);
363 extern int blkdev_reset_zones_ioctl(struct block_device *bdev, fmode_t mode,
364 				    unsigned int cmd, unsigned long arg);
365 
366 #else /* CONFIG_BLK_DEV_ZONED */
367 
368 static inline int blkdev_report_zones_ioctl(struct block_device *bdev,
369 					    fmode_t mode, unsigned int cmd,
370 					    unsigned long arg)
371 {
372 	return -ENOTTY;
373 }
374 
375 static inline int blkdev_reset_zones_ioctl(struct block_device *bdev,
376 					   fmode_t mode, unsigned int cmd,
377 					   unsigned long arg)
378 {
379 	return -ENOTTY;
380 }
381 
382 #endif /* CONFIG_BLK_DEV_ZONED */
383 
384 struct request_queue {
385 	/*
386 	 * Together with queue_head for cacheline sharing
387 	 */
388 	struct list_head	queue_head;
389 	struct request		*last_merge;
390 	struct elevator_queue	*elevator;
391 	int			nr_rqs[2];	/* # allocated [a]sync rqs */
392 	int			nr_rqs_elvpriv;	/* # allocated rqs w/ elvpriv */
393 
394 	struct blk_queue_stats	*stats;
395 	struct rq_wb		*rq_wb;
396 
397 	/*
398 	 * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
399 	 * is used, root blkg allocates from @q->root_rl and all other
400 	 * blkgs from their own blkg->rl.  Which one to use should be
401 	 * determined using bio_request_list().
402 	 */
403 	struct request_list	root_rl;
404 
405 	request_fn_proc		*request_fn;
406 	make_request_fn		*make_request_fn;
407 	prep_rq_fn		*prep_rq_fn;
408 	unprep_rq_fn		*unprep_rq_fn;
409 	softirq_done_fn		*softirq_done_fn;
410 	rq_timed_out_fn		*rq_timed_out_fn;
411 	dma_drain_needed_fn	*dma_drain_needed;
412 	lld_busy_fn		*lld_busy_fn;
413 	init_rq_fn		*init_rq_fn;
414 	exit_rq_fn		*exit_rq_fn;
415 
416 	const struct blk_mq_ops	*mq_ops;
417 
418 	unsigned int		*mq_map;
419 
420 	/* sw queues */
421 	struct blk_mq_ctx __percpu	*queue_ctx;
422 	unsigned int		nr_queues;
423 
424 	unsigned int		queue_depth;
425 
426 	/* hw dispatch queues */
427 	struct blk_mq_hw_ctx	**queue_hw_ctx;
428 	unsigned int		nr_hw_queues;
429 
430 	/*
431 	 * Dispatch queue sorting
432 	 */
433 	sector_t		end_sector;
434 	struct request		*boundary_rq;
435 
436 	/*
437 	 * Delayed queue handling
438 	 */
439 	struct delayed_work	delay_work;
440 
441 	struct backing_dev_info	*backing_dev_info;
442 
443 	/*
444 	 * The queue owner gets to use this for whatever they like.
445 	 * ll_rw_blk doesn't touch it.
446 	 */
447 	void			*queuedata;
448 
449 	/*
450 	 * various queue flags, see QUEUE_* below
451 	 */
452 	unsigned long		queue_flags;
453 
454 	/*
455 	 * ida allocated id for this queue.  Used to index queues from
456 	 * ioctx.
457 	 */
458 	int			id;
459 
460 	/*
461 	 * queue needs bounce pages for pages above this limit
462 	 */
463 	gfp_t			bounce_gfp;
464 
465 	/*
466 	 * protects queue structures from reentrancy. ->__queue_lock should
467 	 * _never_ be used directly, it is queue private. always use
468 	 * ->queue_lock.
469 	 */
470 	spinlock_t		__queue_lock;
471 	spinlock_t		*queue_lock;
472 
473 	/*
474 	 * queue kobject
475 	 */
476 	struct kobject kobj;
477 
478 	/*
479 	 * mq queue kobject
480 	 */
481 	struct kobject mq_kobj;
482 
483 #ifdef  CONFIG_BLK_DEV_INTEGRITY
484 	struct blk_integrity integrity;
485 #endif	/* CONFIG_BLK_DEV_INTEGRITY */
486 
487 #ifdef CONFIG_PM
488 	struct device		*dev;
489 	int			rpm_status;
490 	unsigned int		nr_pending;
491 #endif
492 
493 	/*
494 	 * queue settings
495 	 */
496 	unsigned long		nr_requests;	/* Max # of requests */
497 	unsigned int		nr_congestion_on;
498 	unsigned int		nr_congestion_off;
499 	unsigned int		nr_batching;
500 
501 	unsigned int		dma_drain_size;
502 	void			*dma_drain_buffer;
503 	unsigned int		dma_pad_mask;
504 	unsigned int		dma_alignment;
505 
506 	struct blk_queue_tag	*queue_tags;
507 	struct list_head	tag_busy_list;
508 
509 	unsigned int		nr_sorted;
510 	unsigned int		in_flight[2];
511 
512 	/*
513 	 * Number of active block driver functions for which blk_drain_queue()
514 	 * must wait. Must be incremented around functions that unlock the
515 	 * queue_lock internally, e.g. scsi_request_fn().
516 	 */
517 	unsigned int		request_fn_active;
518 
519 	unsigned int		rq_timeout;
520 	int			poll_nsec;
521 
522 	struct blk_stat_callback	*poll_cb;
523 	struct blk_rq_stat	poll_stat[BLK_MQ_POLL_STATS_BKTS];
524 
525 	struct timer_list	timeout;
526 	struct work_struct	timeout_work;
527 	struct list_head	timeout_list;
528 
529 	struct list_head	icq_list;
530 #ifdef CONFIG_BLK_CGROUP
531 	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
532 	struct blkcg_gq		*root_blkg;
533 	struct list_head	blkg_list;
534 #endif
535 
536 	struct queue_limits	limits;
537 
538 	/*
539 	 * sg stuff
540 	 */
541 	unsigned int		sg_timeout;
542 	unsigned int		sg_reserved_size;
543 	int			node;
544 #ifdef CONFIG_BLK_DEV_IO_TRACE
545 	struct blk_trace	*blk_trace;
546 #endif
547 	/*
548 	 * for flush operations
549 	 */
550 	struct blk_flush_queue	*fq;
551 
552 	struct list_head	requeue_list;
553 	spinlock_t		requeue_lock;
554 	struct delayed_work	requeue_work;
555 
556 	struct mutex		sysfs_lock;
557 
558 	int			bypass_depth;
559 	atomic_t		mq_freeze_depth;
560 
561 #if defined(CONFIG_BLK_DEV_BSG)
562 	bsg_job_fn		*bsg_job_fn;
563 	int			bsg_job_size;
564 	struct bsg_class_device bsg_dev;
565 #endif
566 
567 #ifdef CONFIG_BLK_DEV_THROTTLING
568 	/* Throttle data */
569 	struct throtl_data *td;
570 #endif
571 	struct rcu_head		rcu_head;
572 	wait_queue_head_t	mq_freeze_wq;
573 	struct percpu_ref	q_usage_counter;
574 	struct list_head	all_q_node;
575 
576 	struct blk_mq_tag_set	*tag_set;
577 	struct list_head	tag_set_list;
578 	struct bio_set		*bio_split;
579 
580 #ifdef CONFIG_BLK_DEBUG_FS
581 	struct dentry		*debugfs_dir;
582 	struct dentry		*sched_debugfs_dir;
583 #endif
584 
585 	bool			mq_sysfs_init_done;
586 
587 	size_t			cmd_size;
588 	void			*rq_alloc_data;
589 };
590 
591 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
592 #define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
593 #define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
594 #define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
595 #define QUEUE_FLAG_DYING	5	/* queue being torn down */
596 #define QUEUE_FLAG_BYPASS	6	/* act as dumb FIFO queue */
597 #define QUEUE_FLAG_BIDI		7	/* queue supports bidi requests */
598 #define QUEUE_FLAG_NOMERGES     8	/* disable merge attempts */
599 #define QUEUE_FLAG_SAME_COMP	9	/* complete on same CPU-group */
600 #define QUEUE_FLAG_FAIL_IO     10	/* fake timeout */
601 #define QUEUE_FLAG_STACKABLE   11	/* supports request stacking */
602 #define QUEUE_FLAG_NONROT      12	/* non-rotational device (SSD) */
603 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
604 #define QUEUE_FLAG_IO_STAT     13	/* do IO stats */
605 #define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
606 #define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
607 #define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
608 #define QUEUE_FLAG_SECERASE    17	/* supports secure erase */
609 #define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
610 #define QUEUE_FLAG_DEAD        19	/* queue tear-down finished */
611 #define QUEUE_FLAG_INIT_DONE   20	/* queue is initialized */
612 #define QUEUE_FLAG_NO_SG_MERGE 21	/* don't attempt to merge SG segments*/
613 #define QUEUE_FLAG_POLL	       22	/* IO polling enabled if set */
614 #define QUEUE_FLAG_WC	       23	/* Write back caching */
615 #define QUEUE_FLAG_FUA	       24	/* device supports FUA writes */
616 #define QUEUE_FLAG_FLUSH_NQ    25	/* flush not queueuable */
617 #define QUEUE_FLAG_DAX         26	/* device supports DAX */
618 #define QUEUE_FLAG_STATS       27	/* track rq completion times */
619 #define QUEUE_FLAG_POLL_STATS  28	/* collecting stats for hybrid polling */
620 #define QUEUE_FLAG_REGISTERED  29	/* queue has been registered to a disk */
621 
622 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
623 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
624 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
625 				 (1 << QUEUE_FLAG_ADD_RANDOM))
626 
627 #define QUEUE_FLAG_MQ_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
628 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
629 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
630 				 (1 << QUEUE_FLAG_POLL))
631 
632 static inline void queue_lockdep_assert_held(struct request_queue *q)
633 {
634 	if (q->queue_lock)
635 		lockdep_assert_held(q->queue_lock);
636 }
637 
638 static inline void queue_flag_set_unlocked(unsigned int flag,
639 					   struct request_queue *q)
640 {
641 	__set_bit(flag, &q->queue_flags);
642 }
643 
644 static inline int queue_flag_test_and_clear(unsigned int flag,
645 					    struct request_queue *q)
646 {
647 	queue_lockdep_assert_held(q);
648 
649 	if (test_bit(flag, &q->queue_flags)) {
650 		__clear_bit(flag, &q->queue_flags);
651 		return 1;
652 	}
653 
654 	return 0;
655 }
656 
657 static inline int queue_flag_test_and_set(unsigned int flag,
658 					  struct request_queue *q)
659 {
660 	queue_lockdep_assert_held(q);
661 
662 	if (!test_bit(flag, &q->queue_flags)) {
663 		__set_bit(flag, &q->queue_flags);
664 		return 0;
665 	}
666 
667 	return 1;
668 }
669 
670 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
671 {
672 	queue_lockdep_assert_held(q);
673 	__set_bit(flag, &q->queue_flags);
674 }
675 
676 static inline void queue_flag_clear_unlocked(unsigned int flag,
677 					     struct request_queue *q)
678 {
679 	__clear_bit(flag, &q->queue_flags);
680 }
681 
682 static inline int queue_in_flight(struct request_queue *q)
683 {
684 	return q->in_flight[0] + q->in_flight[1];
685 }
686 
687 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
688 {
689 	queue_lockdep_assert_held(q);
690 	__clear_bit(flag, &q->queue_flags);
691 }
692 
693 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
694 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
695 #define blk_queue_dying(q)	test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
696 #define blk_queue_dead(q)	test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
697 #define blk_queue_bypass(q)	test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
698 #define blk_queue_init_done(q)	test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
699 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
700 #define blk_queue_noxmerges(q)	\
701 	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
702 #define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
703 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
704 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
705 #define blk_queue_stackable(q)	\
706 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
707 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
708 #define blk_queue_secure_erase(q) \
709 	(test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags))
710 #define blk_queue_dax(q)	test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
711 
712 #define blk_noretry_request(rq) \
713 	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
714 			     REQ_FAILFAST_DRIVER))
715 
716 static inline bool blk_account_rq(struct request *rq)
717 {
718 	return (rq->rq_flags & RQF_STARTED) && !blk_rq_is_passthrough(rq);
719 }
720 
721 #define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
722 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
723 /* rq->queuelist of dequeued request must be list_empty() */
724 #define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
725 
726 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
727 
728 #define rq_data_dir(rq)		(op_is_write(req_op(rq)) ? WRITE : READ)
729 
730 /*
731  * Driver can handle struct request, if it either has an old style
732  * request_fn defined, or is blk-mq based.
733  */
734 static inline bool queue_is_rq_based(struct request_queue *q)
735 {
736 	return q->request_fn || q->mq_ops;
737 }
738 
739 static inline unsigned int blk_queue_cluster(struct request_queue *q)
740 {
741 	return q->limits.cluster;
742 }
743 
744 static inline enum blk_zoned_model
745 blk_queue_zoned_model(struct request_queue *q)
746 {
747 	return q->limits.zoned;
748 }
749 
750 static inline bool blk_queue_is_zoned(struct request_queue *q)
751 {
752 	switch (blk_queue_zoned_model(q)) {
753 	case BLK_ZONED_HA:
754 	case BLK_ZONED_HM:
755 		return true;
756 	default:
757 		return false;
758 	}
759 }
760 
761 static inline unsigned int blk_queue_zone_sectors(struct request_queue *q)
762 {
763 	return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0;
764 }
765 
766 static inline bool rq_is_sync(struct request *rq)
767 {
768 	return op_is_sync(rq->cmd_flags);
769 }
770 
771 static inline bool blk_rl_full(struct request_list *rl, bool sync)
772 {
773 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
774 
775 	return rl->flags & flag;
776 }
777 
778 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
779 {
780 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
781 
782 	rl->flags |= flag;
783 }
784 
785 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
786 {
787 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
788 
789 	rl->flags &= ~flag;
790 }
791 
792 static inline bool rq_mergeable(struct request *rq)
793 {
794 	if (blk_rq_is_passthrough(rq))
795 		return false;
796 
797 	if (req_op(rq) == REQ_OP_FLUSH)
798 		return false;
799 
800 	if (req_op(rq) == REQ_OP_WRITE_ZEROES)
801 		return false;
802 
803 	if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
804 		return false;
805 	if (rq->rq_flags & RQF_NOMERGE_FLAGS)
806 		return false;
807 
808 	return true;
809 }
810 
811 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
812 {
813 	if (bio_data(a) == bio_data(b))
814 		return true;
815 
816 	return false;
817 }
818 
819 static inline unsigned int blk_queue_depth(struct request_queue *q)
820 {
821 	if (q->queue_depth)
822 		return q->queue_depth;
823 
824 	return q->nr_requests;
825 }
826 
827 /*
828  * q->prep_rq_fn return values
829  */
830 enum {
831 	BLKPREP_OK,		/* serve it */
832 	BLKPREP_KILL,		/* fatal error, kill, return -EIO */
833 	BLKPREP_DEFER,		/* leave on queue */
834 	BLKPREP_INVALID,	/* invalid command, kill, return -EREMOTEIO */
835 };
836 
837 extern unsigned long blk_max_low_pfn, blk_max_pfn;
838 
839 /*
840  * standard bounce addresses:
841  *
842  * BLK_BOUNCE_HIGH	: bounce all highmem pages
843  * BLK_BOUNCE_ANY	: don't bounce anything
844  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
845  */
846 
847 #if BITS_PER_LONG == 32
848 #define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
849 #else
850 #define BLK_BOUNCE_HIGH		-1ULL
851 #endif
852 #define BLK_BOUNCE_ANY		(-1ULL)
853 #define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
854 
855 /*
856  * default timeout for SG_IO if none specified
857  */
858 #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
859 #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
860 
861 #ifdef CONFIG_BOUNCE
862 extern int init_emergency_isa_pool(void);
863 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
864 #else
865 static inline int init_emergency_isa_pool(void)
866 {
867 	return 0;
868 }
869 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
870 {
871 }
872 #endif /* CONFIG_MMU */
873 
874 struct rq_map_data {
875 	struct page **pages;
876 	int page_order;
877 	int nr_entries;
878 	unsigned long offset;
879 	int null_mapped;
880 	int from_user;
881 };
882 
883 struct req_iterator {
884 	struct bvec_iter iter;
885 	struct bio *bio;
886 };
887 
888 /* This should not be used directly - use rq_for_each_segment */
889 #define for_each_bio(_bio)		\
890 	for (; _bio; _bio = _bio->bi_next)
891 #define __rq_for_each_bio(_bio, rq)	\
892 	if ((rq->bio))			\
893 		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
894 
895 #define rq_for_each_segment(bvl, _rq, _iter)			\
896 	__rq_for_each_bio(_iter.bio, _rq)			\
897 		bio_for_each_segment(bvl, _iter.bio, _iter.iter)
898 
899 #define rq_iter_last(bvec, _iter)				\
900 		(_iter.bio->bi_next == NULL &&			\
901 		 bio_iter_last(bvec, _iter.iter))
902 
903 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
904 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
905 #endif
906 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
907 extern void rq_flush_dcache_pages(struct request *rq);
908 #else
909 static inline void rq_flush_dcache_pages(struct request *rq)
910 {
911 }
912 #endif
913 
914 #ifdef CONFIG_PRINTK
915 #define vfs_msg(sb, level, fmt, ...)				\
916 	__vfs_msg(sb, level, fmt, ##__VA_ARGS__)
917 #else
918 #define vfs_msg(sb, level, fmt, ...)				\
919 do {								\
920 	no_printk(fmt, ##__VA_ARGS__);				\
921 	__vfs_msg(sb, "", " ");					\
922 } while (0)
923 #endif
924 
925 extern int blk_register_queue(struct gendisk *disk);
926 extern void blk_unregister_queue(struct gendisk *disk);
927 extern blk_qc_t generic_make_request(struct bio *bio);
928 extern void blk_rq_init(struct request_queue *q, struct request *rq);
929 extern void blk_init_request_from_bio(struct request *req, struct bio *bio);
930 extern void blk_put_request(struct request *);
931 extern void __blk_put_request(struct request_queue *, struct request *);
932 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
933 extern void blk_requeue_request(struct request_queue *, struct request *);
934 extern int blk_lld_busy(struct request_queue *q);
935 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
936 			     struct bio_set *bs, gfp_t gfp_mask,
937 			     int (*bio_ctr)(struct bio *, struct bio *, void *),
938 			     void *data);
939 extern void blk_rq_unprep_clone(struct request *rq);
940 extern int blk_insert_cloned_request(struct request_queue *q,
941 				     struct request *rq);
942 extern int blk_rq_append_bio(struct request *rq, struct bio *bio);
943 extern void blk_delay_queue(struct request_queue *, unsigned long);
944 extern void blk_queue_split(struct request_queue *, struct bio **,
945 			    struct bio_set *);
946 extern void blk_recount_segments(struct request_queue *, struct bio *);
947 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
948 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
949 			      unsigned int, void __user *);
950 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
951 			  unsigned int, void __user *);
952 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
953 			 struct scsi_ioctl_command __user *);
954 
955 extern int blk_queue_enter(struct request_queue *q, bool nowait);
956 extern void blk_queue_exit(struct request_queue *q);
957 extern void blk_start_queue(struct request_queue *q);
958 extern void blk_start_queue_async(struct request_queue *q);
959 extern void blk_stop_queue(struct request_queue *q);
960 extern void blk_sync_queue(struct request_queue *q);
961 extern void __blk_stop_queue(struct request_queue *q);
962 extern void __blk_run_queue(struct request_queue *q);
963 extern void __blk_run_queue_uncond(struct request_queue *q);
964 extern void blk_run_queue(struct request_queue *);
965 extern void blk_run_queue_async(struct request_queue *q);
966 extern void blk_mq_quiesce_queue(struct request_queue *q);
967 extern int blk_rq_map_user(struct request_queue *, struct request *,
968 			   struct rq_map_data *, void __user *, unsigned long,
969 			   gfp_t);
970 extern int blk_rq_unmap_user(struct bio *);
971 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
972 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
973 			       struct rq_map_data *, const struct iov_iter *,
974 			       gfp_t);
975 extern void blk_execute_rq(struct request_queue *, struct gendisk *,
976 			  struct request *, int);
977 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
978 				  struct request *, int, rq_end_io_fn *);
979 
980 bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
981 
982 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
983 {
984 	return bdev->bd_disk->queue;	/* this is never NULL */
985 }
986 
987 /*
988  * blk_rq_pos()			: the current sector
989  * blk_rq_bytes()		: bytes left in the entire request
990  * blk_rq_cur_bytes()		: bytes left in the current segment
991  * blk_rq_err_bytes()		: bytes left till the next error boundary
992  * blk_rq_sectors()		: sectors left in the entire request
993  * blk_rq_cur_sectors()		: sectors left in the current segment
994  */
995 static inline sector_t blk_rq_pos(const struct request *rq)
996 {
997 	return rq->__sector;
998 }
999 
1000 static inline unsigned int blk_rq_bytes(const struct request *rq)
1001 {
1002 	return rq->__data_len;
1003 }
1004 
1005 static inline int blk_rq_cur_bytes(const struct request *rq)
1006 {
1007 	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
1008 }
1009 
1010 extern unsigned int blk_rq_err_bytes(const struct request *rq);
1011 
1012 static inline unsigned int blk_rq_sectors(const struct request *rq)
1013 {
1014 	return blk_rq_bytes(rq) >> 9;
1015 }
1016 
1017 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
1018 {
1019 	return blk_rq_cur_bytes(rq) >> 9;
1020 }
1021 
1022 /*
1023  * Some commands like WRITE SAME have a payload or data transfer size which
1024  * is different from the size of the request.  Any driver that supports such
1025  * commands using the RQF_SPECIAL_PAYLOAD flag needs to use this helper to
1026  * calculate the data transfer size.
1027  */
1028 static inline unsigned int blk_rq_payload_bytes(struct request *rq)
1029 {
1030 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
1031 		return rq->special_vec.bv_len;
1032 	return blk_rq_bytes(rq);
1033 }
1034 
1035 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
1036 						     int op)
1037 {
1038 	if (unlikely(op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE))
1039 		return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
1040 
1041 	if (unlikely(op == REQ_OP_WRITE_SAME))
1042 		return q->limits.max_write_same_sectors;
1043 
1044 	if (unlikely(op == REQ_OP_WRITE_ZEROES))
1045 		return q->limits.max_write_zeroes_sectors;
1046 
1047 	return q->limits.max_sectors;
1048 }
1049 
1050 /*
1051  * Return maximum size of a request at given offset. Only valid for
1052  * file system requests.
1053  */
1054 static inline unsigned int blk_max_size_offset(struct request_queue *q,
1055 					       sector_t offset)
1056 {
1057 	if (!q->limits.chunk_sectors)
1058 		return q->limits.max_sectors;
1059 
1060 	return q->limits.chunk_sectors -
1061 			(offset & (q->limits.chunk_sectors - 1));
1062 }
1063 
1064 static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
1065 						  sector_t offset)
1066 {
1067 	struct request_queue *q = rq->q;
1068 
1069 	if (blk_rq_is_passthrough(rq))
1070 		return q->limits.max_hw_sectors;
1071 
1072 	if (!q->limits.chunk_sectors ||
1073 	    req_op(rq) == REQ_OP_DISCARD ||
1074 	    req_op(rq) == REQ_OP_SECURE_ERASE)
1075 		return blk_queue_get_max_sectors(q, req_op(rq));
1076 
1077 	return min(blk_max_size_offset(q, offset),
1078 			blk_queue_get_max_sectors(q, req_op(rq)));
1079 }
1080 
1081 static inline unsigned int blk_rq_count_bios(struct request *rq)
1082 {
1083 	unsigned int nr_bios = 0;
1084 	struct bio *bio;
1085 
1086 	__rq_for_each_bio(bio, rq)
1087 		nr_bios++;
1088 
1089 	return nr_bios;
1090 }
1091 
1092 /*
1093  * Request issue related functions.
1094  */
1095 extern struct request *blk_peek_request(struct request_queue *q);
1096 extern void blk_start_request(struct request *rq);
1097 extern struct request *blk_fetch_request(struct request_queue *q);
1098 
1099 /*
1100  * Request completion related functions.
1101  *
1102  * blk_update_request() completes given number of bytes and updates
1103  * the request without completing it.
1104  *
1105  * blk_end_request() and friends.  __blk_end_request() must be called
1106  * with the request queue spinlock acquired.
1107  *
1108  * Several drivers define their own end_request and call
1109  * blk_end_request() for parts of the original function.
1110  * This prevents code duplication in drivers.
1111  */
1112 extern bool blk_update_request(struct request *rq, int error,
1113 			       unsigned int nr_bytes);
1114 extern void blk_finish_request(struct request *rq, int error);
1115 extern bool blk_end_request(struct request *rq, int error,
1116 			    unsigned int nr_bytes);
1117 extern void blk_end_request_all(struct request *rq, int error);
1118 extern bool __blk_end_request(struct request *rq, int error,
1119 			      unsigned int nr_bytes);
1120 extern void __blk_end_request_all(struct request *rq, int error);
1121 extern bool __blk_end_request_cur(struct request *rq, int error);
1122 
1123 extern void blk_complete_request(struct request *);
1124 extern void __blk_complete_request(struct request *);
1125 extern void blk_abort_request(struct request *);
1126 extern void blk_unprep_request(struct request *);
1127 
1128 /*
1129  * Access functions for manipulating queue properties
1130  */
1131 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
1132 					spinlock_t *lock, int node_id);
1133 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
1134 extern int blk_init_allocated_queue(struct request_queue *);
1135 extern void blk_cleanup_queue(struct request_queue *);
1136 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
1137 extern void blk_queue_bounce_limit(struct request_queue *, u64);
1138 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
1139 extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
1140 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
1141 extern void blk_queue_max_discard_segments(struct request_queue *,
1142 		unsigned short);
1143 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
1144 extern void blk_queue_max_discard_sectors(struct request_queue *q,
1145 		unsigned int max_discard_sectors);
1146 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
1147 		unsigned int max_write_same_sectors);
1148 extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
1149 		unsigned int max_write_same_sectors);
1150 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
1151 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
1152 extern void blk_queue_alignment_offset(struct request_queue *q,
1153 				       unsigned int alignment);
1154 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
1155 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
1156 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
1157 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
1158 extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth);
1159 extern void blk_set_default_limits(struct queue_limits *lim);
1160 extern void blk_set_stacking_limits(struct queue_limits *lim);
1161 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
1162 			    sector_t offset);
1163 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
1164 			    sector_t offset);
1165 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
1166 			      sector_t offset);
1167 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
1168 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
1169 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
1170 extern int blk_queue_dma_drain(struct request_queue *q,
1171 			       dma_drain_needed_fn *dma_drain_needed,
1172 			       void *buf, unsigned int size);
1173 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
1174 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
1175 extern void blk_queue_virt_boundary(struct request_queue *, unsigned long);
1176 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
1177 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
1178 extern void blk_queue_dma_alignment(struct request_queue *, int);
1179 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
1180 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
1181 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
1182 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
1183 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
1184 extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fua);
1185 
1186 /*
1187  * Number of physical segments as sent to the device.
1188  *
1189  * Normally this is the number of discontiguous data segments sent by the
1190  * submitter.  But for data-less command like discard we might have no
1191  * actual data segments submitted, but the driver might have to add it's
1192  * own special payload.  In that case we still return 1 here so that this
1193  * special payload will be mapped.
1194  */
1195 static inline unsigned short blk_rq_nr_phys_segments(struct request *rq)
1196 {
1197 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
1198 		return 1;
1199 	return rq->nr_phys_segments;
1200 }
1201 
1202 /*
1203  * Number of discard segments (or ranges) the driver needs to fill in.
1204  * Each discard bio merged into a request is counted as one segment.
1205  */
1206 static inline unsigned short blk_rq_nr_discard_segments(struct request *rq)
1207 {
1208 	return max_t(unsigned short, rq->nr_phys_segments, 1);
1209 }
1210 
1211 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
1212 extern void blk_dump_rq_flags(struct request *, char *);
1213 extern long nr_blockdev_pages(void);
1214 
1215 bool __must_check blk_get_queue(struct request_queue *);
1216 struct request_queue *blk_alloc_queue(gfp_t);
1217 struct request_queue *blk_alloc_queue_node(gfp_t, int);
1218 extern void blk_put_queue(struct request_queue *);
1219 extern void blk_set_queue_dying(struct request_queue *);
1220 
1221 /*
1222  * block layer runtime pm functions
1223  */
1224 #ifdef CONFIG_PM
1225 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
1226 extern int blk_pre_runtime_suspend(struct request_queue *q);
1227 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
1228 extern void blk_pre_runtime_resume(struct request_queue *q);
1229 extern void blk_post_runtime_resume(struct request_queue *q, int err);
1230 extern void blk_set_runtime_active(struct request_queue *q);
1231 #else
1232 static inline void blk_pm_runtime_init(struct request_queue *q,
1233 	struct device *dev) {}
1234 static inline int blk_pre_runtime_suspend(struct request_queue *q)
1235 {
1236 	return -ENOSYS;
1237 }
1238 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
1239 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
1240 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1241 static inline void blk_set_runtime_active(struct request_queue *q) {}
1242 #endif
1243 
1244 /*
1245  * blk_plug permits building a queue of related requests by holding the I/O
1246  * fragments for a short period. This allows merging of sequential requests
1247  * into single larger request. As the requests are moved from a per-task list to
1248  * the device's request_queue in a batch, this results in improved scalability
1249  * as the lock contention for request_queue lock is reduced.
1250  *
1251  * It is ok not to disable preemption when adding the request to the plug list
1252  * or when attempting a merge, because blk_schedule_flush_list() will only flush
1253  * the plug list when the task sleeps by itself. For details, please see
1254  * schedule() where blk_schedule_flush_plug() is called.
1255  */
1256 struct blk_plug {
1257 	struct list_head list; /* requests */
1258 	struct list_head mq_list; /* blk-mq requests */
1259 	struct list_head cb_list; /* md requires an unplug callback */
1260 };
1261 #define BLK_MAX_REQUEST_COUNT 16
1262 #define BLK_PLUG_FLUSH_SIZE (128 * 1024)
1263 
1264 struct blk_plug_cb;
1265 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1266 struct blk_plug_cb {
1267 	struct list_head list;
1268 	blk_plug_cb_fn callback;
1269 	void *data;
1270 };
1271 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1272 					     void *data, int size);
1273 extern void blk_start_plug(struct blk_plug *);
1274 extern void blk_finish_plug(struct blk_plug *);
1275 extern void blk_flush_plug_list(struct blk_plug *, bool);
1276 
1277 static inline void blk_flush_plug(struct task_struct *tsk)
1278 {
1279 	struct blk_plug *plug = tsk->plug;
1280 
1281 	if (plug)
1282 		blk_flush_plug_list(plug, false);
1283 }
1284 
1285 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1286 {
1287 	struct blk_plug *plug = tsk->plug;
1288 
1289 	if (plug)
1290 		blk_flush_plug_list(plug, true);
1291 }
1292 
1293 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1294 {
1295 	struct blk_plug *plug = tsk->plug;
1296 
1297 	return plug &&
1298 		(!list_empty(&plug->list) ||
1299 		 !list_empty(&plug->mq_list) ||
1300 		 !list_empty(&plug->cb_list));
1301 }
1302 
1303 /*
1304  * tag stuff
1305  */
1306 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1307 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1308 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1309 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
1310 extern void blk_queue_free_tags(struct request_queue *);
1311 extern int blk_queue_resize_tags(struct request_queue *, int);
1312 extern void blk_queue_invalidate_tags(struct request_queue *);
1313 extern struct blk_queue_tag *blk_init_tags(int, int);
1314 extern void blk_free_tags(struct blk_queue_tag *);
1315 
1316 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1317 						int tag)
1318 {
1319 	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1320 		return NULL;
1321 	return bqt->tag_index[tag];
1322 }
1323 
1324 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1325 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1326 		sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1327 
1328 #define BLKDEV_DISCARD_SECURE	(1 << 0)	/* issue a secure erase */
1329 
1330 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1331 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1332 extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1333 		sector_t nr_sects, gfp_t gfp_mask, int flags,
1334 		struct bio **biop);
1335 
1336 #define BLKDEV_ZERO_NOUNMAP	(1 << 0)  /* do not free blocks */
1337 #define BLKDEV_ZERO_NOFALLBACK	(1 << 1)  /* don't write explicit zeroes */
1338 
1339 extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1340 		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
1341 		unsigned flags);
1342 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1343 		sector_t nr_sects, gfp_t gfp_mask, unsigned flags);
1344 
1345 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1346 		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1347 {
1348 	return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1349 				    nr_blocks << (sb->s_blocksize_bits - 9),
1350 				    gfp_mask, flags);
1351 }
1352 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1353 		sector_t nr_blocks, gfp_t gfp_mask)
1354 {
1355 	return blkdev_issue_zeroout(sb->s_bdev,
1356 				    block << (sb->s_blocksize_bits - 9),
1357 				    nr_blocks << (sb->s_blocksize_bits - 9),
1358 				    gfp_mask, 0);
1359 }
1360 
1361 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1362 
1363 enum blk_default_limits {
1364 	BLK_MAX_SEGMENTS	= 128,
1365 	BLK_SAFE_MAX_SECTORS	= 255,
1366 	BLK_DEF_MAX_SECTORS	= 2560,
1367 	BLK_MAX_SEGMENT_SIZE	= 65536,
1368 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
1369 };
1370 
1371 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1372 
1373 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1374 {
1375 	return q->limits.bounce_pfn;
1376 }
1377 
1378 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1379 {
1380 	return q->limits.seg_boundary_mask;
1381 }
1382 
1383 static inline unsigned long queue_virt_boundary(struct request_queue *q)
1384 {
1385 	return q->limits.virt_boundary_mask;
1386 }
1387 
1388 static inline unsigned int queue_max_sectors(struct request_queue *q)
1389 {
1390 	return q->limits.max_sectors;
1391 }
1392 
1393 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1394 {
1395 	return q->limits.max_hw_sectors;
1396 }
1397 
1398 static inline unsigned short queue_max_segments(struct request_queue *q)
1399 {
1400 	return q->limits.max_segments;
1401 }
1402 
1403 static inline unsigned short queue_max_discard_segments(struct request_queue *q)
1404 {
1405 	return q->limits.max_discard_segments;
1406 }
1407 
1408 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1409 {
1410 	return q->limits.max_segment_size;
1411 }
1412 
1413 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1414 {
1415 	int retval = 512;
1416 
1417 	if (q && q->limits.logical_block_size)
1418 		retval = q->limits.logical_block_size;
1419 
1420 	return retval;
1421 }
1422 
1423 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1424 {
1425 	return queue_logical_block_size(bdev_get_queue(bdev));
1426 }
1427 
1428 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1429 {
1430 	return q->limits.physical_block_size;
1431 }
1432 
1433 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1434 {
1435 	return queue_physical_block_size(bdev_get_queue(bdev));
1436 }
1437 
1438 static inline unsigned int queue_io_min(struct request_queue *q)
1439 {
1440 	return q->limits.io_min;
1441 }
1442 
1443 static inline int bdev_io_min(struct block_device *bdev)
1444 {
1445 	return queue_io_min(bdev_get_queue(bdev));
1446 }
1447 
1448 static inline unsigned int queue_io_opt(struct request_queue *q)
1449 {
1450 	return q->limits.io_opt;
1451 }
1452 
1453 static inline int bdev_io_opt(struct block_device *bdev)
1454 {
1455 	return queue_io_opt(bdev_get_queue(bdev));
1456 }
1457 
1458 static inline int queue_alignment_offset(struct request_queue *q)
1459 {
1460 	if (q->limits.misaligned)
1461 		return -1;
1462 
1463 	return q->limits.alignment_offset;
1464 }
1465 
1466 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1467 {
1468 	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1469 	unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
1470 
1471 	return (granularity + lim->alignment_offset - alignment) % granularity;
1472 }
1473 
1474 static inline int bdev_alignment_offset(struct block_device *bdev)
1475 {
1476 	struct request_queue *q = bdev_get_queue(bdev);
1477 
1478 	if (q->limits.misaligned)
1479 		return -1;
1480 
1481 	if (bdev != bdev->bd_contains)
1482 		return bdev->bd_part->alignment_offset;
1483 
1484 	return q->limits.alignment_offset;
1485 }
1486 
1487 static inline int queue_discard_alignment(struct request_queue *q)
1488 {
1489 	if (q->limits.discard_misaligned)
1490 		return -1;
1491 
1492 	return q->limits.discard_alignment;
1493 }
1494 
1495 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1496 {
1497 	unsigned int alignment, granularity, offset;
1498 
1499 	if (!lim->max_discard_sectors)
1500 		return 0;
1501 
1502 	/* Why are these in bytes, not sectors? */
1503 	alignment = lim->discard_alignment >> 9;
1504 	granularity = lim->discard_granularity >> 9;
1505 	if (!granularity)
1506 		return 0;
1507 
1508 	/* Offset of the partition start in 'granularity' sectors */
1509 	offset = sector_div(sector, granularity);
1510 
1511 	/* And why do we do this modulus *again* in blkdev_issue_discard()? */
1512 	offset = (granularity + alignment - offset) % granularity;
1513 
1514 	/* Turn it back into bytes, gaah */
1515 	return offset << 9;
1516 }
1517 
1518 static inline int bdev_discard_alignment(struct block_device *bdev)
1519 {
1520 	struct request_queue *q = bdev_get_queue(bdev);
1521 
1522 	if (bdev != bdev->bd_contains)
1523 		return bdev->bd_part->discard_alignment;
1524 
1525 	return q->limits.discard_alignment;
1526 }
1527 
1528 static inline unsigned int bdev_write_same(struct block_device *bdev)
1529 {
1530 	struct request_queue *q = bdev_get_queue(bdev);
1531 
1532 	if (q)
1533 		return q->limits.max_write_same_sectors;
1534 
1535 	return 0;
1536 }
1537 
1538 static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev)
1539 {
1540 	struct request_queue *q = bdev_get_queue(bdev);
1541 
1542 	if (q)
1543 		return q->limits.max_write_zeroes_sectors;
1544 
1545 	return 0;
1546 }
1547 
1548 static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev)
1549 {
1550 	struct request_queue *q = bdev_get_queue(bdev);
1551 
1552 	if (q)
1553 		return blk_queue_zoned_model(q);
1554 
1555 	return BLK_ZONED_NONE;
1556 }
1557 
1558 static inline bool bdev_is_zoned(struct block_device *bdev)
1559 {
1560 	struct request_queue *q = bdev_get_queue(bdev);
1561 
1562 	if (q)
1563 		return blk_queue_is_zoned(q);
1564 
1565 	return false;
1566 }
1567 
1568 static inline unsigned int bdev_zone_sectors(struct block_device *bdev)
1569 {
1570 	struct request_queue *q = bdev_get_queue(bdev);
1571 
1572 	if (q)
1573 		return blk_queue_zone_sectors(q);
1574 
1575 	return 0;
1576 }
1577 
1578 static inline int queue_dma_alignment(struct request_queue *q)
1579 {
1580 	return q ? q->dma_alignment : 511;
1581 }
1582 
1583 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1584 				 unsigned int len)
1585 {
1586 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1587 	return !(addr & alignment) && !(len & alignment);
1588 }
1589 
1590 /* assumes size > 256 */
1591 static inline unsigned int blksize_bits(unsigned int size)
1592 {
1593 	unsigned int bits = 8;
1594 	do {
1595 		bits++;
1596 		size >>= 1;
1597 	} while (size > 256);
1598 	return bits;
1599 }
1600 
1601 static inline unsigned int block_size(struct block_device *bdev)
1602 {
1603 	return bdev->bd_block_size;
1604 }
1605 
1606 static inline bool queue_flush_queueable(struct request_queue *q)
1607 {
1608 	return !test_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
1609 }
1610 
1611 typedef struct {struct page *v;} Sector;
1612 
1613 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1614 
1615 static inline void put_dev_sector(Sector p)
1616 {
1617 	put_page(p.v);
1618 }
1619 
1620 static inline bool __bvec_gap_to_prev(struct request_queue *q,
1621 				struct bio_vec *bprv, unsigned int offset)
1622 {
1623 	return offset ||
1624 		((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
1625 }
1626 
1627 /*
1628  * Check if adding a bio_vec after bprv with offset would create a gap in
1629  * the SG list. Most drivers don't care about this, but some do.
1630  */
1631 static inline bool bvec_gap_to_prev(struct request_queue *q,
1632 				struct bio_vec *bprv, unsigned int offset)
1633 {
1634 	if (!queue_virt_boundary(q))
1635 		return false;
1636 	return __bvec_gap_to_prev(q, bprv, offset);
1637 }
1638 
1639 /*
1640  * Check if the two bvecs from two bios can be merged to one segment.
1641  * If yes, no need to check gap between the two bios since the 1st bio
1642  * and the 1st bvec in the 2nd bio can be handled in one segment.
1643  */
1644 static inline bool bios_segs_mergeable(struct request_queue *q,
1645 		struct bio *prev, struct bio_vec *prev_last_bv,
1646 		struct bio_vec *next_first_bv)
1647 {
1648 	if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv))
1649 		return false;
1650 	if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv))
1651 		return false;
1652 	if (prev->bi_seg_back_size + next_first_bv->bv_len >
1653 			queue_max_segment_size(q))
1654 		return false;
1655 	return true;
1656 }
1657 
1658 static inline bool bio_will_gap(struct request_queue *q,
1659 				struct request *prev_rq,
1660 				struct bio *prev,
1661 				struct bio *next)
1662 {
1663 	if (bio_has_data(prev) && queue_virt_boundary(q)) {
1664 		struct bio_vec pb, nb;
1665 
1666 		/*
1667 		 * don't merge if the 1st bio starts with non-zero
1668 		 * offset, otherwise it is quite difficult to respect
1669 		 * sg gap limit. We work hard to merge a huge number of small
1670 		 * single bios in case of mkfs.
1671 		 */
1672 		if (prev_rq)
1673 			bio_get_first_bvec(prev_rq->bio, &pb);
1674 		else
1675 			bio_get_first_bvec(prev, &pb);
1676 		if (pb.bv_offset)
1677 			return true;
1678 
1679 		/*
1680 		 * We don't need to worry about the situation that the
1681 		 * merged segment ends in unaligned virt boundary:
1682 		 *
1683 		 * - if 'pb' ends aligned, the merged segment ends aligned
1684 		 * - if 'pb' ends unaligned, the next bio must include
1685 		 *   one single bvec of 'nb', otherwise the 'nb' can't
1686 		 *   merge with 'pb'
1687 		 */
1688 		bio_get_last_bvec(prev, &pb);
1689 		bio_get_first_bvec(next, &nb);
1690 
1691 		if (!bios_segs_mergeable(q, prev, &pb, &nb))
1692 			return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
1693 	}
1694 
1695 	return false;
1696 }
1697 
1698 static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
1699 {
1700 	return bio_will_gap(req->q, req, req->biotail, bio);
1701 }
1702 
1703 static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
1704 {
1705 	return bio_will_gap(req->q, NULL, bio, req->bio);
1706 }
1707 
1708 int kblockd_schedule_work(struct work_struct *work);
1709 int kblockd_schedule_work_on(int cpu, struct work_struct *work);
1710 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
1711 int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1712 int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1713 
1714 #ifdef CONFIG_BLK_CGROUP
1715 /*
1716  * This should not be using sched_clock(). A real patch is in progress
1717  * to fix this up, until that is in place we need to disable preemption
1718  * around sched_clock() in this function and set_io_start_time_ns().
1719  */
1720 static inline void set_start_time_ns(struct request *req)
1721 {
1722 	preempt_disable();
1723 	req->start_time_ns = sched_clock();
1724 	preempt_enable();
1725 }
1726 
1727 static inline void set_io_start_time_ns(struct request *req)
1728 {
1729 	preempt_disable();
1730 	req->io_start_time_ns = sched_clock();
1731 	preempt_enable();
1732 }
1733 
1734 static inline uint64_t rq_start_time_ns(struct request *req)
1735 {
1736         return req->start_time_ns;
1737 }
1738 
1739 static inline uint64_t rq_io_start_time_ns(struct request *req)
1740 {
1741         return req->io_start_time_ns;
1742 }
1743 #else
1744 static inline void set_start_time_ns(struct request *req) {}
1745 static inline void set_io_start_time_ns(struct request *req) {}
1746 static inline uint64_t rq_start_time_ns(struct request *req)
1747 {
1748 	return 0;
1749 }
1750 static inline uint64_t rq_io_start_time_ns(struct request *req)
1751 {
1752 	return 0;
1753 }
1754 #endif
1755 
1756 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1757 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1758 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1759 	MODULE_ALIAS("block-major-" __stringify(major) "-*")
1760 
1761 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1762 
1763 enum blk_integrity_flags {
1764 	BLK_INTEGRITY_VERIFY		= 1 << 0,
1765 	BLK_INTEGRITY_GENERATE		= 1 << 1,
1766 	BLK_INTEGRITY_DEVICE_CAPABLE	= 1 << 2,
1767 	BLK_INTEGRITY_IP_CHECKSUM	= 1 << 3,
1768 };
1769 
1770 struct blk_integrity_iter {
1771 	void			*prot_buf;
1772 	void			*data_buf;
1773 	sector_t		seed;
1774 	unsigned int		data_size;
1775 	unsigned short		interval;
1776 	const char		*disk_name;
1777 };
1778 
1779 typedef int (integrity_processing_fn) (struct blk_integrity_iter *);
1780 
1781 struct blk_integrity_profile {
1782 	integrity_processing_fn		*generate_fn;
1783 	integrity_processing_fn		*verify_fn;
1784 	const char			*name;
1785 };
1786 
1787 extern void blk_integrity_register(struct gendisk *, struct blk_integrity *);
1788 extern void blk_integrity_unregister(struct gendisk *);
1789 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1790 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1791 				   struct scatterlist *);
1792 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1793 extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
1794 				   struct request *);
1795 extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
1796 				    struct bio *);
1797 
1798 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1799 {
1800 	struct blk_integrity *bi = &disk->queue->integrity;
1801 
1802 	if (!bi->profile)
1803 		return NULL;
1804 
1805 	return bi;
1806 }
1807 
1808 static inline
1809 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1810 {
1811 	return blk_get_integrity(bdev->bd_disk);
1812 }
1813 
1814 static inline bool blk_integrity_rq(struct request *rq)
1815 {
1816 	return rq->cmd_flags & REQ_INTEGRITY;
1817 }
1818 
1819 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1820 						    unsigned int segs)
1821 {
1822 	q->limits.max_integrity_segments = segs;
1823 }
1824 
1825 static inline unsigned short
1826 queue_max_integrity_segments(struct request_queue *q)
1827 {
1828 	return q->limits.max_integrity_segments;
1829 }
1830 
1831 static inline bool integrity_req_gap_back_merge(struct request *req,
1832 						struct bio *next)
1833 {
1834 	struct bio_integrity_payload *bip = bio_integrity(req->bio);
1835 	struct bio_integrity_payload *bip_next = bio_integrity(next);
1836 
1837 	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1838 				bip_next->bip_vec[0].bv_offset);
1839 }
1840 
1841 static inline bool integrity_req_gap_front_merge(struct request *req,
1842 						 struct bio *bio)
1843 {
1844 	struct bio_integrity_payload *bip = bio_integrity(bio);
1845 	struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
1846 
1847 	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1848 				bip_next->bip_vec[0].bv_offset);
1849 }
1850 
1851 #else /* CONFIG_BLK_DEV_INTEGRITY */
1852 
1853 struct bio;
1854 struct block_device;
1855 struct gendisk;
1856 struct blk_integrity;
1857 
1858 static inline int blk_integrity_rq(struct request *rq)
1859 {
1860 	return 0;
1861 }
1862 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1863 					    struct bio *b)
1864 {
1865 	return 0;
1866 }
1867 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1868 					  struct bio *b,
1869 					  struct scatterlist *s)
1870 {
1871 	return 0;
1872 }
1873 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1874 {
1875 	return NULL;
1876 }
1877 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1878 {
1879 	return NULL;
1880 }
1881 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1882 {
1883 	return 0;
1884 }
1885 static inline void blk_integrity_register(struct gendisk *d,
1886 					 struct blk_integrity *b)
1887 {
1888 }
1889 static inline void blk_integrity_unregister(struct gendisk *d)
1890 {
1891 }
1892 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1893 						    unsigned int segs)
1894 {
1895 }
1896 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1897 {
1898 	return 0;
1899 }
1900 static inline bool blk_integrity_merge_rq(struct request_queue *rq,
1901 					  struct request *r1,
1902 					  struct request *r2)
1903 {
1904 	return true;
1905 }
1906 static inline bool blk_integrity_merge_bio(struct request_queue *rq,
1907 					   struct request *r,
1908 					   struct bio *b)
1909 {
1910 	return true;
1911 }
1912 
1913 static inline bool integrity_req_gap_back_merge(struct request *req,
1914 						struct bio *next)
1915 {
1916 	return false;
1917 }
1918 static inline bool integrity_req_gap_front_merge(struct request *req,
1919 						 struct bio *bio)
1920 {
1921 	return false;
1922 }
1923 
1924 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1925 
1926 struct block_device_operations {
1927 	int (*open) (struct block_device *, fmode_t);
1928 	void (*release) (struct gendisk *, fmode_t);
1929 	int (*rw_page)(struct block_device *, sector_t, struct page *, bool);
1930 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1931 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1932 	unsigned int (*check_events) (struct gendisk *disk,
1933 				      unsigned int clearing);
1934 	/* ->media_changed() is DEPRECATED, use ->check_events() instead */
1935 	int (*media_changed) (struct gendisk *);
1936 	void (*unlock_native_capacity) (struct gendisk *);
1937 	int (*revalidate_disk) (struct gendisk *);
1938 	int (*getgeo)(struct block_device *, struct hd_geometry *);
1939 	/* this callback is with swap_lock and sometimes page table lock held */
1940 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1941 	struct module *owner;
1942 	const struct pr_ops *pr_ops;
1943 };
1944 
1945 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1946 				 unsigned long);
1947 extern int bdev_read_page(struct block_device *, sector_t, struct page *);
1948 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
1949 						struct writeback_control *);
1950 #else /* CONFIG_BLOCK */
1951 
1952 struct block_device;
1953 
1954 /*
1955  * stubs for when the block layer is configured out
1956  */
1957 #define buffer_heads_over_limit 0
1958 
1959 static inline long nr_blockdev_pages(void)
1960 {
1961 	return 0;
1962 }
1963 
1964 struct blk_plug {
1965 };
1966 
1967 static inline void blk_start_plug(struct blk_plug *plug)
1968 {
1969 }
1970 
1971 static inline void blk_finish_plug(struct blk_plug *plug)
1972 {
1973 }
1974 
1975 static inline void blk_flush_plug(struct task_struct *task)
1976 {
1977 }
1978 
1979 static inline void blk_schedule_flush_plug(struct task_struct *task)
1980 {
1981 }
1982 
1983 
1984 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1985 {
1986 	return false;
1987 }
1988 
1989 static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
1990 				     sector_t *error_sector)
1991 {
1992 	return 0;
1993 }
1994 
1995 #endif /* CONFIG_BLOCK */
1996 
1997 #endif
1998