xref: /linux-6.15/include/linux/blkdev.h (revision baa41469)
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 	atomic_t		shared_hctx_restart;
395 
396 	struct blk_queue_stats	*stats;
397 	struct rq_wb		*rq_wb;
398 
399 	/*
400 	 * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
401 	 * is used, root blkg allocates from @q->root_rl and all other
402 	 * blkgs from their own blkg->rl.  Which one to use should be
403 	 * determined using bio_request_list().
404 	 */
405 	struct request_list	root_rl;
406 
407 	request_fn_proc		*request_fn;
408 	make_request_fn		*make_request_fn;
409 	prep_rq_fn		*prep_rq_fn;
410 	unprep_rq_fn		*unprep_rq_fn;
411 	softirq_done_fn		*softirq_done_fn;
412 	rq_timed_out_fn		*rq_timed_out_fn;
413 	dma_drain_needed_fn	*dma_drain_needed;
414 	lld_busy_fn		*lld_busy_fn;
415 	init_rq_fn		*init_rq_fn;
416 	exit_rq_fn		*exit_rq_fn;
417 
418 	const struct blk_mq_ops	*mq_ops;
419 
420 	unsigned int		*mq_map;
421 
422 	/* sw queues */
423 	struct blk_mq_ctx __percpu	*queue_ctx;
424 	unsigned int		nr_queues;
425 
426 	unsigned int		queue_depth;
427 
428 	/* hw dispatch queues */
429 	struct blk_mq_hw_ctx	**queue_hw_ctx;
430 	unsigned int		nr_hw_queues;
431 
432 	/*
433 	 * Dispatch queue sorting
434 	 */
435 	sector_t		end_sector;
436 	struct request		*boundary_rq;
437 
438 	/*
439 	 * Delayed queue handling
440 	 */
441 	struct delayed_work	delay_work;
442 
443 	struct backing_dev_info	*backing_dev_info;
444 
445 	/*
446 	 * The queue owner gets to use this for whatever they like.
447 	 * ll_rw_blk doesn't touch it.
448 	 */
449 	void			*queuedata;
450 
451 	/*
452 	 * various queue flags, see QUEUE_* below
453 	 */
454 	unsigned long		queue_flags;
455 
456 	/*
457 	 * ida allocated id for this queue.  Used to index queues from
458 	 * ioctx.
459 	 */
460 	int			id;
461 
462 	/*
463 	 * queue needs bounce pages for pages above this limit
464 	 */
465 	gfp_t			bounce_gfp;
466 
467 	/*
468 	 * protects queue structures from reentrancy. ->__queue_lock should
469 	 * _never_ be used directly, it is queue private. always use
470 	 * ->queue_lock.
471 	 */
472 	spinlock_t		__queue_lock;
473 	spinlock_t		*queue_lock;
474 
475 	/*
476 	 * queue kobject
477 	 */
478 	struct kobject kobj;
479 
480 	/*
481 	 * mq queue kobject
482 	 */
483 	struct kobject mq_kobj;
484 
485 #ifdef  CONFIG_BLK_DEV_INTEGRITY
486 	struct blk_integrity integrity;
487 #endif	/* CONFIG_BLK_DEV_INTEGRITY */
488 
489 #ifdef CONFIG_PM
490 	struct device		*dev;
491 	int			rpm_status;
492 	unsigned int		nr_pending;
493 #endif
494 
495 	/*
496 	 * queue settings
497 	 */
498 	unsigned long		nr_requests;	/* Max # of requests */
499 	unsigned int		nr_congestion_on;
500 	unsigned int		nr_congestion_off;
501 	unsigned int		nr_batching;
502 
503 	unsigned int		dma_drain_size;
504 	void			*dma_drain_buffer;
505 	unsigned int		dma_pad_mask;
506 	unsigned int		dma_alignment;
507 
508 	struct blk_queue_tag	*queue_tags;
509 	struct list_head	tag_busy_list;
510 
511 	unsigned int		nr_sorted;
512 	unsigned int		in_flight[2];
513 
514 	/*
515 	 * Number of active block driver functions for which blk_drain_queue()
516 	 * must wait. Must be incremented around functions that unlock the
517 	 * queue_lock internally, e.g. scsi_request_fn().
518 	 */
519 	unsigned int		request_fn_active;
520 
521 	unsigned int		rq_timeout;
522 	int			poll_nsec;
523 
524 	struct blk_stat_callback	*poll_cb;
525 	struct blk_rq_stat	poll_stat[BLK_MQ_POLL_STATS_BKTS];
526 
527 	struct timer_list	timeout;
528 	struct work_struct	timeout_work;
529 	struct list_head	timeout_list;
530 
531 	struct list_head	icq_list;
532 #ifdef CONFIG_BLK_CGROUP
533 	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
534 	struct blkcg_gq		*root_blkg;
535 	struct list_head	blkg_list;
536 #endif
537 
538 	struct queue_limits	limits;
539 
540 	/*
541 	 * sg stuff
542 	 */
543 	unsigned int		sg_timeout;
544 	unsigned int		sg_reserved_size;
545 	int			node;
546 #ifdef CONFIG_BLK_DEV_IO_TRACE
547 	struct blk_trace	*blk_trace;
548 #endif
549 	/*
550 	 * for flush operations
551 	 */
552 	struct blk_flush_queue	*fq;
553 
554 	struct list_head	requeue_list;
555 	spinlock_t		requeue_lock;
556 	struct delayed_work	requeue_work;
557 
558 	struct mutex		sysfs_lock;
559 
560 	int			bypass_depth;
561 	atomic_t		mq_freeze_depth;
562 
563 #if defined(CONFIG_BLK_DEV_BSG)
564 	bsg_job_fn		*bsg_job_fn;
565 	int			bsg_job_size;
566 	struct bsg_class_device bsg_dev;
567 #endif
568 
569 #ifdef CONFIG_BLK_DEV_THROTTLING
570 	/* Throttle data */
571 	struct throtl_data *td;
572 #endif
573 	struct rcu_head		rcu_head;
574 	wait_queue_head_t	mq_freeze_wq;
575 	struct percpu_ref	q_usage_counter;
576 	struct list_head	all_q_node;
577 
578 	struct blk_mq_tag_set	*tag_set;
579 	struct list_head	tag_set_list;
580 	struct bio_set		*bio_split;
581 
582 #ifdef CONFIG_BLK_DEBUG_FS
583 	struct dentry		*debugfs_dir;
584 	struct dentry		*sched_debugfs_dir;
585 #endif
586 
587 	bool			mq_sysfs_init_done;
588 
589 	size_t			cmd_size;
590 	void			*rq_alloc_data;
591 
592 	struct work_struct	release_work;
593 };
594 
595 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
596 #define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
597 #define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
598 #define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
599 #define QUEUE_FLAG_DYING	5	/* queue being torn down */
600 #define QUEUE_FLAG_BYPASS	6	/* act as dumb FIFO queue */
601 #define QUEUE_FLAG_BIDI		7	/* queue supports bidi requests */
602 #define QUEUE_FLAG_NOMERGES     8	/* disable merge attempts */
603 #define QUEUE_FLAG_SAME_COMP	9	/* complete on same CPU-group */
604 #define QUEUE_FLAG_FAIL_IO     10	/* fake timeout */
605 #define QUEUE_FLAG_STACKABLE   11	/* supports request stacking */
606 #define QUEUE_FLAG_NONROT      12	/* non-rotational device (SSD) */
607 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
608 #define QUEUE_FLAG_IO_STAT     13	/* do IO stats */
609 #define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
610 #define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
611 #define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
612 #define QUEUE_FLAG_SECERASE    17	/* supports secure erase */
613 #define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
614 #define QUEUE_FLAG_DEAD        19	/* queue tear-down finished */
615 #define QUEUE_FLAG_INIT_DONE   20	/* queue is initialized */
616 #define QUEUE_FLAG_NO_SG_MERGE 21	/* don't attempt to merge SG segments*/
617 #define QUEUE_FLAG_POLL	       22	/* IO polling enabled if set */
618 #define QUEUE_FLAG_WC	       23	/* Write back caching */
619 #define QUEUE_FLAG_FUA	       24	/* device supports FUA writes */
620 #define QUEUE_FLAG_FLUSH_NQ    25	/* flush not queueuable */
621 #define QUEUE_FLAG_DAX         26	/* device supports DAX */
622 #define QUEUE_FLAG_STATS       27	/* track rq completion times */
623 #define QUEUE_FLAG_POLL_STATS  28	/* collecting stats for hybrid polling */
624 #define QUEUE_FLAG_REGISTERED  29	/* queue has been registered to a disk */
625 
626 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
627 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
628 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
629 				 (1 << QUEUE_FLAG_ADD_RANDOM))
630 
631 #define QUEUE_FLAG_MQ_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
632 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
633 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
634 				 (1 << QUEUE_FLAG_POLL))
635 
636 static inline void queue_lockdep_assert_held(struct request_queue *q)
637 {
638 	if (q->queue_lock)
639 		lockdep_assert_held(q->queue_lock);
640 }
641 
642 static inline void queue_flag_set_unlocked(unsigned int flag,
643 					   struct request_queue *q)
644 {
645 	__set_bit(flag, &q->queue_flags);
646 }
647 
648 static inline int queue_flag_test_and_clear(unsigned int flag,
649 					    struct request_queue *q)
650 {
651 	queue_lockdep_assert_held(q);
652 
653 	if (test_bit(flag, &q->queue_flags)) {
654 		__clear_bit(flag, &q->queue_flags);
655 		return 1;
656 	}
657 
658 	return 0;
659 }
660 
661 static inline int queue_flag_test_and_set(unsigned int flag,
662 					  struct request_queue *q)
663 {
664 	queue_lockdep_assert_held(q);
665 
666 	if (!test_bit(flag, &q->queue_flags)) {
667 		__set_bit(flag, &q->queue_flags);
668 		return 0;
669 	}
670 
671 	return 1;
672 }
673 
674 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
675 {
676 	queue_lockdep_assert_held(q);
677 	__set_bit(flag, &q->queue_flags);
678 }
679 
680 static inline void queue_flag_clear_unlocked(unsigned int flag,
681 					     struct request_queue *q)
682 {
683 	__clear_bit(flag, &q->queue_flags);
684 }
685 
686 static inline int queue_in_flight(struct request_queue *q)
687 {
688 	return q->in_flight[0] + q->in_flight[1];
689 }
690 
691 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
692 {
693 	queue_lockdep_assert_held(q);
694 	__clear_bit(flag, &q->queue_flags);
695 }
696 
697 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
698 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
699 #define blk_queue_dying(q)	test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
700 #define blk_queue_dead(q)	test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
701 #define blk_queue_bypass(q)	test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
702 #define blk_queue_init_done(q)	test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
703 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
704 #define blk_queue_noxmerges(q)	\
705 	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
706 #define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
707 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
708 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
709 #define blk_queue_stackable(q)	\
710 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
711 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
712 #define blk_queue_secure_erase(q) \
713 	(test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags))
714 #define blk_queue_dax(q)	test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
715 
716 #define blk_noretry_request(rq) \
717 	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
718 			     REQ_FAILFAST_DRIVER))
719 
720 static inline bool blk_account_rq(struct request *rq)
721 {
722 	return (rq->rq_flags & RQF_STARTED) && !blk_rq_is_passthrough(rq);
723 }
724 
725 #define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
726 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
727 /* rq->queuelist of dequeued request must be list_empty() */
728 #define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
729 
730 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
731 
732 #define rq_data_dir(rq)		(op_is_write(req_op(rq)) ? WRITE : READ)
733 
734 /*
735  * Driver can handle struct request, if it either has an old style
736  * request_fn defined, or is blk-mq based.
737  */
738 static inline bool queue_is_rq_based(struct request_queue *q)
739 {
740 	return q->request_fn || q->mq_ops;
741 }
742 
743 static inline unsigned int blk_queue_cluster(struct request_queue *q)
744 {
745 	return q->limits.cluster;
746 }
747 
748 static inline enum blk_zoned_model
749 blk_queue_zoned_model(struct request_queue *q)
750 {
751 	return q->limits.zoned;
752 }
753 
754 static inline bool blk_queue_is_zoned(struct request_queue *q)
755 {
756 	switch (blk_queue_zoned_model(q)) {
757 	case BLK_ZONED_HA:
758 	case BLK_ZONED_HM:
759 		return true;
760 	default:
761 		return false;
762 	}
763 }
764 
765 static inline unsigned int blk_queue_zone_sectors(struct request_queue *q)
766 {
767 	return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0;
768 }
769 
770 static inline bool rq_is_sync(struct request *rq)
771 {
772 	return op_is_sync(rq->cmd_flags);
773 }
774 
775 static inline bool blk_rl_full(struct request_list *rl, bool sync)
776 {
777 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
778 
779 	return rl->flags & flag;
780 }
781 
782 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
783 {
784 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
785 
786 	rl->flags |= flag;
787 }
788 
789 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
790 {
791 	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
792 
793 	rl->flags &= ~flag;
794 }
795 
796 static inline bool rq_mergeable(struct request *rq)
797 {
798 	if (blk_rq_is_passthrough(rq))
799 		return false;
800 
801 	if (req_op(rq) == REQ_OP_FLUSH)
802 		return false;
803 
804 	if (req_op(rq) == REQ_OP_WRITE_ZEROES)
805 		return false;
806 
807 	if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
808 		return false;
809 	if (rq->rq_flags & RQF_NOMERGE_FLAGS)
810 		return false;
811 
812 	return true;
813 }
814 
815 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
816 {
817 	if (bio_data(a) == bio_data(b))
818 		return true;
819 
820 	return false;
821 }
822 
823 static inline unsigned int blk_queue_depth(struct request_queue *q)
824 {
825 	if (q->queue_depth)
826 		return q->queue_depth;
827 
828 	return q->nr_requests;
829 }
830 
831 /*
832  * q->prep_rq_fn return values
833  */
834 enum {
835 	BLKPREP_OK,		/* serve it */
836 	BLKPREP_KILL,		/* fatal error, kill, return -EIO */
837 	BLKPREP_DEFER,		/* leave on queue */
838 	BLKPREP_INVALID,	/* invalid command, kill, return -EREMOTEIO */
839 };
840 
841 extern unsigned long blk_max_low_pfn, blk_max_pfn;
842 
843 /*
844  * standard bounce addresses:
845  *
846  * BLK_BOUNCE_HIGH	: bounce all highmem pages
847  * BLK_BOUNCE_ANY	: don't bounce anything
848  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
849  */
850 
851 #if BITS_PER_LONG == 32
852 #define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
853 #else
854 #define BLK_BOUNCE_HIGH		-1ULL
855 #endif
856 #define BLK_BOUNCE_ANY		(-1ULL)
857 #define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
858 
859 /*
860  * default timeout for SG_IO if none specified
861  */
862 #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
863 #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
864 
865 #ifdef CONFIG_BOUNCE
866 extern int init_emergency_isa_pool(void);
867 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
868 #else
869 static inline int init_emergency_isa_pool(void)
870 {
871 	return 0;
872 }
873 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
874 {
875 }
876 #endif /* CONFIG_MMU */
877 
878 struct rq_map_data {
879 	struct page **pages;
880 	int page_order;
881 	int nr_entries;
882 	unsigned long offset;
883 	int null_mapped;
884 	int from_user;
885 };
886 
887 struct req_iterator {
888 	struct bvec_iter iter;
889 	struct bio *bio;
890 };
891 
892 /* This should not be used directly - use rq_for_each_segment */
893 #define for_each_bio(_bio)		\
894 	for (; _bio; _bio = _bio->bi_next)
895 #define __rq_for_each_bio(_bio, rq)	\
896 	if ((rq->bio))			\
897 		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
898 
899 #define rq_for_each_segment(bvl, _rq, _iter)			\
900 	__rq_for_each_bio(_iter.bio, _rq)			\
901 		bio_for_each_segment(bvl, _iter.bio, _iter.iter)
902 
903 #define rq_iter_last(bvec, _iter)				\
904 		(_iter.bio->bi_next == NULL &&			\
905 		 bio_iter_last(bvec, _iter.iter))
906 
907 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
908 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
909 #endif
910 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
911 extern void rq_flush_dcache_pages(struct request *rq);
912 #else
913 static inline void rq_flush_dcache_pages(struct request *rq)
914 {
915 }
916 #endif
917 
918 #ifdef CONFIG_PRINTK
919 #define vfs_msg(sb, level, fmt, ...)				\
920 	__vfs_msg(sb, level, fmt, ##__VA_ARGS__)
921 #else
922 #define vfs_msg(sb, level, fmt, ...)				\
923 do {								\
924 	no_printk(fmt, ##__VA_ARGS__);				\
925 	__vfs_msg(sb, "", " ");					\
926 } while (0)
927 #endif
928 
929 extern int blk_register_queue(struct gendisk *disk);
930 extern void blk_unregister_queue(struct gendisk *disk);
931 extern blk_qc_t generic_make_request(struct bio *bio);
932 extern void blk_rq_init(struct request_queue *q, struct request *rq);
933 extern void blk_init_request_from_bio(struct request *req, struct bio *bio);
934 extern void blk_put_request(struct request *);
935 extern void __blk_put_request(struct request_queue *, struct request *);
936 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
937 extern void blk_requeue_request(struct request_queue *, struct request *);
938 extern int blk_lld_busy(struct request_queue *q);
939 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
940 			     struct bio_set *bs, gfp_t gfp_mask,
941 			     int (*bio_ctr)(struct bio *, struct bio *, void *),
942 			     void *data);
943 extern void blk_rq_unprep_clone(struct request *rq);
944 extern int blk_insert_cloned_request(struct request_queue *q,
945 				     struct request *rq);
946 extern int blk_rq_append_bio(struct request *rq, struct bio *bio);
947 extern void blk_delay_queue(struct request_queue *, unsigned long);
948 extern void blk_queue_split(struct request_queue *, struct bio **,
949 			    struct bio_set *);
950 extern void blk_recount_segments(struct request_queue *, struct bio *);
951 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
952 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
953 			      unsigned int, void __user *);
954 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
955 			  unsigned int, void __user *);
956 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
957 			 struct scsi_ioctl_command __user *);
958 
959 extern int blk_queue_enter(struct request_queue *q, bool nowait);
960 extern void blk_queue_exit(struct request_queue *q);
961 extern void blk_start_queue(struct request_queue *q);
962 extern void blk_start_queue_async(struct request_queue *q);
963 extern void blk_stop_queue(struct request_queue *q);
964 extern void blk_sync_queue(struct request_queue *q);
965 extern void __blk_stop_queue(struct request_queue *q);
966 extern void __blk_run_queue(struct request_queue *q);
967 extern void __blk_run_queue_uncond(struct request_queue *q);
968 extern void blk_run_queue(struct request_queue *);
969 extern void blk_run_queue_async(struct request_queue *q);
970 extern void blk_mq_quiesce_queue(struct request_queue *q);
971 extern int blk_rq_map_user(struct request_queue *, struct request *,
972 			   struct rq_map_data *, void __user *, unsigned long,
973 			   gfp_t);
974 extern int blk_rq_unmap_user(struct bio *);
975 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
976 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
977 			       struct rq_map_data *, const struct iov_iter *,
978 			       gfp_t);
979 extern void blk_execute_rq(struct request_queue *, struct gendisk *,
980 			  struct request *, int);
981 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
982 				  struct request *, int, rq_end_io_fn *);
983 
984 bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
985 
986 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
987 {
988 	return bdev->bd_disk->queue;	/* this is never NULL */
989 }
990 
991 /*
992  * blk_rq_pos()			: the current sector
993  * blk_rq_bytes()		: bytes left in the entire request
994  * blk_rq_cur_bytes()		: bytes left in the current segment
995  * blk_rq_err_bytes()		: bytes left till the next error boundary
996  * blk_rq_sectors()		: sectors left in the entire request
997  * blk_rq_cur_sectors()		: sectors left in the current segment
998  */
999 static inline sector_t blk_rq_pos(const struct request *rq)
1000 {
1001 	return rq->__sector;
1002 }
1003 
1004 static inline unsigned int blk_rq_bytes(const struct request *rq)
1005 {
1006 	return rq->__data_len;
1007 }
1008 
1009 static inline int blk_rq_cur_bytes(const struct request *rq)
1010 {
1011 	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
1012 }
1013 
1014 extern unsigned int blk_rq_err_bytes(const struct request *rq);
1015 
1016 static inline unsigned int blk_rq_sectors(const struct request *rq)
1017 {
1018 	return blk_rq_bytes(rq) >> 9;
1019 }
1020 
1021 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
1022 {
1023 	return blk_rq_cur_bytes(rq) >> 9;
1024 }
1025 
1026 /*
1027  * Some commands like WRITE SAME have a payload or data transfer size which
1028  * is different from the size of the request.  Any driver that supports such
1029  * commands using the RQF_SPECIAL_PAYLOAD flag needs to use this helper to
1030  * calculate the data transfer size.
1031  */
1032 static inline unsigned int blk_rq_payload_bytes(struct request *rq)
1033 {
1034 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
1035 		return rq->special_vec.bv_len;
1036 	return blk_rq_bytes(rq);
1037 }
1038 
1039 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
1040 						     int op)
1041 {
1042 	if (unlikely(op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE))
1043 		return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
1044 
1045 	if (unlikely(op == REQ_OP_WRITE_SAME))
1046 		return q->limits.max_write_same_sectors;
1047 
1048 	if (unlikely(op == REQ_OP_WRITE_ZEROES))
1049 		return q->limits.max_write_zeroes_sectors;
1050 
1051 	return q->limits.max_sectors;
1052 }
1053 
1054 /*
1055  * Return maximum size of a request at given offset. Only valid for
1056  * file system requests.
1057  */
1058 static inline unsigned int blk_max_size_offset(struct request_queue *q,
1059 					       sector_t offset)
1060 {
1061 	if (!q->limits.chunk_sectors)
1062 		return q->limits.max_sectors;
1063 
1064 	return q->limits.chunk_sectors -
1065 			(offset & (q->limits.chunk_sectors - 1));
1066 }
1067 
1068 static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
1069 						  sector_t offset)
1070 {
1071 	struct request_queue *q = rq->q;
1072 
1073 	if (blk_rq_is_passthrough(rq))
1074 		return q->limits.max_hw_sectors;
1075 
1076 	if (!q->limits.chunk_sectors ||
1077 	    req_op(rq) == REQ_OP_DISCARD ||
1078 	    req_op(rq) == REQ_OP_SECURE_ERASE)
1079 		return blk_queue_get_max_sectors(q, req_op(rq));
1080 
1081 	return min(blk_max_size_offset(q, offset),
1082 			blk_queue_get_max_sectors(q, req_op(rq)));
1083 }
1084 
1085 static inline unsigned int blk_rq_count_bios(struct request *rq)
1086 {
1087 	unsigned int nr_bios = 0;
1088 	struct bio *bio;
1089 
1090 	__rq_for_each_bio(bio, rq)
1091 		nr_bios++;
1092 
1093 	return nr_bios;
1094 }
1095 
1096 /*
1097  * Request issue related functions.
1098  */
1099 extern struct request *blk_peek_request(struct request_queue *q);
1100 extern void blk_start_request(struct request *rq);
1101 extern struct request *blk_fetch_request(struct request_queue *q);
1102 
1103 /*
1104  * Request completion related functions.
1105  *
1106  * blk_update_request() completes given number of bytes and updates
1107  * the request without completing it.
1108  *
1109  * blk_end_request() and friends.  __blk_end_request() must be called
1110  * with the request queue spinlock acquired.
1111  *
1112  * Several drivers define their own end_request and call
1113  * blk_end_request() for parts of the original function.
1114  * This prevents code duplication in drivers.
1115  */
1116 extern bool blk_update_request(struct request *rq, int error,
1117 			       unsigned int nr_bytes);
1118 extern void blk_finish_request(struct request *rq, int error);
1119 extern bool blk_end_request(struct request *rq, int error,
1120 			    unsigned int nr_bytes);
1121 extern void blk_end_request_all(struct request *rq, int error);
1122 extern bool __blk_end_request(struct request *rq, int error,
1123 			      unsigned int nr_bytes);
1124 extern void __blk_end_request_all(struct request *rq, int error);
1125 extern bool __blk_end_request_cur(struct request *rq, int error);
1126 
1127 extern void blk_complete_request(struct request *);
1128 extern void __blk_complete_request(struct request *);
1129 extern void blk_abort_request(struct request *);
1130 extern void blk_unprep_request(struct request *);
1131 
1132 /*
1133  * Access functions for manipulating queue properties
1134  */
1135 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
1136 					spinlock_t *lock, int node_id);
1137 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
1138 extern int blk_init_allocated_queue(struct request_queue *);
1139 extern void blk_cleanup_queue(struct request_queue *);
1140 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
1141 extern void blk_queue_bounce_limit(struct request_queue *, u64);
1142 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
1143 extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
1144 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
1145 extern void blk_queue_max_discard_segments(struct request_queue *,
1146 		unsigned short);
1147 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
1148 extern void blk_queue_max_discard_sectors(struct request_queue *q,
1149 		unsigned int max_discard_sectors);
1150 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
1151 		unsigned int max_write_same_sectors);
1152 extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
1153 		unsigned int max_write_same_sectors);
1154 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
1155 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
1156 extern void blk_queue_alignment_offset(struct request_queue *q,
1157 				       unsigned int alignment);
1158 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
1159 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
1160 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
1161 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
1162 extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth);
1163 extern void blk_set_default_limits(struct queue_limits *lim);
1164 extern void blk_set_stacking_limits(struct queue_limits *lim);
1165 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
1166 			    sector_t offset);
1167 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
1168 			    sector_t offset);
1169 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
1170 			      sector_t offset);
1171 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
1172 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
1173 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
1174 extern int blk_queue_dma_drain(struct request_queue *q,
1175 			       dma_drain_needed_fn *dma_drain_needed,
1176 			       void *buf, unsigned int size);
1177 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
1178 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
1179 extern void blk_queue_virt_boundary(struct request_queue *, unsigned long);
1180 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
1181 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
1182 extern void blk_queue_dma_alignment(struct request_queue *, int);
1183 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
1184 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
1185 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
1186 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
1187 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
1188 extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fua);
1189 
1190 /*
1191  * Number of physical segments as sent to the device.
1192  *
1193  * Normally this is the number of discontiguous data segments sent by the
1194  * submitter.  But for data-less command like discard we might have no
1195  * actual data segments submitted, but the driver might have to add it's
1196  * own special payload.  In that case we still return 1 here so that this
1197  * special payload will be mapped.
1198  */
1199 static inline unsigned short blk_rq_nr_phys_segments(struct request *rq)
1200 {
1201 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
1202 		return 1;
1203 	return rq->nr_phys_segments;
1204 }
1205 
1206 /*
1207  * Number of discard segments (or ranges) the driver needs to fill in.
1208  * Each discard bio merged into a request is counted as one segment.
1209  */
1210 static inline unsigned short blk_rq_nr_discard_segments(struct request *rq)
1211 {
1212 	return max_t(unsigned short, rq->nr_phys_segments, 1);
1213 }
1214 
1215 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
1216 extern void blk_dump_rq_flags(struct request *, char *);
1217 extern long nr_blockdev_pages(void);
1218 
1219 bool __must_check blk_get_queue(struct request_queue *);
1220 struct request_queue *blk_alloc_queue(gfp_t);
1221 struct request_queue *blk_alloc_queue_node(gfp_t, int);
1222 extern void blk_put_queue(struct request_queue *);
1223 extern void blk_set_queue_dying(struct request_queue *);
1224 
1225 /*
1226  * block layer runtime pm functions
1227  */
1228 #ifdef CONFIG_PM
1229 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
1230 extern int blk_pre_runtime_suspend(struct request_queue *q);
1231 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
1232 extern void blk_pre_runtime_resume(struct request_queue *q);
1233 extern void blk_post_runtime_resume(struct request_queue *q, int err);
1234 extern void blk_set_runtime_active(struct request_queue *q);
1235 #else
1236 static inline void blk_pm_runtime_init(struct request_queue *q,
1237 	struct device *dev) {}
1238 static inline int blk_pre_runtime_suspend(struct request_queue *q)
1239 {
1240 	return -ENOSYS;
1241 }
1242 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
1243 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
1244 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1245 static inline void blk_set_runtime_active(struct request_queue *q) {}
1246 #endif
1247 
1248 /*
1249  * blk_plug permits building a queue of related requests by holding the I/O
1250  * fragments for a short period. This allows merging of sequential requests
1251  * into single larger request. As the requests are moved from a per-task list to
1252  * the device's request_queue in a batch, this results in improved scalability
1253  * as the lock contention for request_queue lock is reduced.
1254  *
1255  * It is ok not to disable preemption when adding the request to the plug list
1256  * or when attempting a merge, because blk_schedule_flush_list() will only flush
1257  * the plug list when the task sleeps by itself. For details, please see
1258  * schedule() where blk_schedule_flush_plug() is called.
1259  */
1260 struct blk_plug {
1261 	struct list_head list; /* requests */
1262 	struct list_head mq_list; /* blk-mq requests */
1263 	struct list_head cb_list; /* md requires an unplug callback */
1264 };
1265 #define BLK_MAX_REQUEST_COUNT 16
1266 #define BLK_PLUG_FLUSH_SIZE (128 * 1024)
1267 
1268 struct blk_plug_cb;
1269 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1270 struct blk_plug_cb {
1271 	struct list_head list;
1272 	blk_plug_cb_fn callback;
1273 	void *data;
1274 };
1275 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1276 					     void *data, int size);
1277 extern void blk_start_plug(struct blk_plug *);
1278 extern void blk_finish_plug(struct blk_plug *);
1279 extern void blk_flush_plug_list(struct blk_plug *, bool);
1280 
1281 static inline void blk_flush_plug(struct task_struct *tsk)
1282 {
1283 	struct blk_plug *plug = tsk->plug;
1284 
1285 	if (plug)
1286 		blk_flush_plug_list(plug, false);
1287 }
1288 
1289 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1290 {
1291 	struct blk_plug *plug = tsk->plug;
1292 
1293 	if (plug)
1294 		blk_flush_plug_list(plug, true);
1295 }
1296 
1297 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1298 {
1299 	struct blk_plug *plug = tsk->plug;
1300 
1301 	return plug &&
1302 		(!list_empty(&plug->list) ||
1303 		 !list_empty(&plug->mq_list) ||
1304 		 !list_empty(&plug->cb_list));
1305 }
1306 
1307 /*
1308  * tag stuff
1309  */
1310 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1311 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1312 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1313 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
1314 extern void blk_queue_free_tags(struct request_queue *);
1315 extern int blk_queue_resize_tags(struct request_queue *, int);
1316 extern void blk_queue_invalidate_tags(struct request_queue *);
1317 extern struct blk_queue_tag *blk_init_tags(int, int);
1318 extern void blk_free_tags(struct blk_queue_tag *);
1319 
1320 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1321 						int tag)
1322 {
1323 	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1324 		return NULL;
1325 	return bqt->tag_index[tag];
1326 }
1327 
1328 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1329 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1330 		sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1331 
1332 #define BLKDEV_DISCARD_SECURE	(1 << 0)	/* issue a secure erase */
1333 
1334 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1335 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1336 extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1337 		sector_t nr_sects, gfp_t gfp_mask, int flags,
1338 		struct bio **biop);
1339 
1340 #define BLKDEV_ZERO_NOUNMAP	(1 << 0)  /* do not free blocks */
1341 #define BLKDEV_ZERO_NOFALLBACK	(1 << 1)  /* don't write explicit zeroes */
1342 
1343 extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1344 		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
1345 		unsigned flags);
1346 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1347 		sector_t nr_sects, gfp_t gfp_mask, unsigned flags);
1348 
1349 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1350 		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1351 {
1352 	return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1353 				    nr_blocks << (sb->s_blocksize_bits - 9),
1354 				    gfp_mask, flags);
1355 }
1356 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1357 		sector_t nr_blocks, gfp_t gfp_mask)
1358 {
1359 	return blkdev_issue_zeroout(sb->s_bdev,
1360 				    block << (sb->s_blocksize_bits - 9),
1361 				    nr_blocks << (sb->s_blocksize_bits - 9),
1362 				    gfp_mask, 0);
1363 }
1364 
1365 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1366 
1367 enum blk_default_limits {
1368 	BLK_MAX_SEGMENTS	= 128,
1369 	BLK_SAFE_MAX_SECTORS	= 255,
1370 	BLK_DEF_MAX_SECTORS	= 2560,
1371 	BLK_MAX_SEGMENT_SIZE	= 65536,
1372 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
1373 };
1374 
1375 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1376 
1377 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1378 {
1379 	return q->limits.bounce_pfn;
1380 }
1381 
1382 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1383 {
1384 	return q->limits.seg_boundary_mask;
1385 }
1386 
1387 static inline unsigned long queue_virt_boundary(struct request_queue *q)
1388 {
1389 	return q->limits.virt_boundary_mask;
1390 }
1391 
1392 static inline unsigned int queue_max_sectors(struct request_queue *q)
1393 {
1394 	return q->limits.max_sectors;
1395 }
1396 
1397 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1398 {
1399 	return q->limits.max_hw_sectors;
1400 }
1401 
1402 static inline unsigned short queue_max_segments(struct request_queue *q)
1403 {
1404 	return q->limits.max_segments;
1405 }
1406 
1407 static inline unsigned short queue_max_discard_segments(struct request_queue *q)
1408 {
1409 	return q->limits.max_discard_segments;
1410 }
1411 
1412 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1413 {
1414 	return q->limits.max_segment_size;
1415 }
1416 
1417 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1418 {
1419 	int retval = 512;
1420 
1421 	if (q && q->limits.logical_block_size)
1422 		retval = q->limits.logical_block_size;
1423 
1424 	return retval;
1425 }
1426 
1427 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1428 {
1429 	return queue_logical_block_size(bdev_get_queue(bdev));
1430 }
1431 
1432 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1433 {
1434 	return q->limits.physical_block_size;
1435 }
1436 
1437 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1438 {
1439 	return queue_physical_block_size(bdev_get_queue(bdev));
1440 }
1441 
1442 static inline unsigned int queue_io_min(struct request_queue *q)
1443 {
1444 	return q->limits.io_min;
1445 }
1446 
1447 static inline int bdev_io_min(struct block_device *bdev)
1448 {
1449 	return queue_io_min(bdev_get_queue(bdev));
1450 }
1451 
1452 static inline unsigned int queue_io_opt(struct request_queue *q)
1453 {
1454 	return q->limits.io_opt;
1455 }
1456 
1457 static inline int bdev_io_opt(struct block_device *bdev)
1458 {
1459 	return queue_io_opt(bdev_get_queue(bdev));
1460 }
1461 
1462 static inline int queue_alignment_offset(struct request_queue *q)
1463 {
1464 	if (q->limits.misaligned)
1465 		return -1;
1466 
1467 	return q->limits.alignment_offset;
1468 }
1469 
1470 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1471 {
1472 	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1473 	unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
1474 
1475 	return (granularity + lim->alignment_offset - alignment) % granularity;
1476 }
1477 
1478 static inline int bdev_alignment_offset(struct block_device *bdev)
1479 {
1480 	struct request_queue *q = bdev_get_queue(bdev);
1481 
1482 	if (q->limits.misaligned)
1483 		return -1;
1484 
1485 	if (bdev != bdev->bd_contains)
1486 		return bdev->bd_part->alignment_offset;
1487 
1488 	return q->limits.alignment_offset;
1489 }
1490 
1491 static inline int queue_discard_alignment(struct request_queue *q)
1492 {
1493 	if (q->limits.discard_misaligned)
1494 		return -1;
1495 
1496 	return q->limits.discard_alignment;
1497 }
1498 
1499 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1500 {
1501 	unsigned int alignment, granularity, offset;
1502 
1503 	if (!lim->max_discard_sectors)
1504 		return 0;
1505 
1506 	/* Why are these in bytes, not sectors? */
1507 	alignment = lim->discard_alignment >> 9;
1508 	granularity = lim->discard_granularity >> 9;
1509 	if (!granularity)
1510 		return 0;
1511 
1512 	/* Offset of the partition start in 'granularity' sectors */
1513 	offset = sector_div(sector, granularity);
1514 
1515 	/* And why do we do this modulus *again* in blkdev_issue_discard()? */
1516 	offset = (granularity + alignment - offset) % granularity;
1517 
1518 	/* Turn it back into bytes, gaah */
1519 	return offset << 9;
1520 }
1521 
1522 static inline int bdev_discard_alignment(struct block_device *bdev)
1523 {
1524 	struct request_queue *q = bdev_get_queue(bdev);
1525 
1526 	if (bdev != bdev->bd_contains)
1527 		return bdev->bd_part->discard_alignment;
1528 
1529 	return q->limits.discard_alignment;
1530 }
1531 
1532 static inline unsigned int bdev_write_same(struct block_device *bdev)
1533 {
1534 	struct request_queue *q = bdev_get_queue(bdev);
1535 
1536 	if (q)
1537 		return q->limits.max_write_same_sectors;
1538 
1539 	return 0;
1540 }
1541 
1542 static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev)
1543 {
1544 	struct request_queue *q = bdev_get_queue(bdev);
1545 
1546 	if (q)
1547 		return q->limits.max_write_zeroes_sectors;
1548 
1549 	return 0;
1550 }
1551 
1552 static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev)
1553 {
1554 	struct request_queue *q = bdev_get_queue(bdev);
1555 
1556 	if (q)
1557 		return blk_queue_zoned_model(q);
1558 
1559 	return BLK_ZONED_NONE;
1560 }
1561 
1562 static inline bool bdev_is_zoned(struct block_device *bdev)
1563 {
1564 	struct request_queue *q = bdev_get_queue(bdev);
1565 
1566 	if (q)
1567 		return blk_queue_is_zoned(q);
1568 
1569 	return false;
1570 }
1571 
1572 static inline unsigned int bdev_zone_sectors(struct block_device *bdev)
1573 {
1574 	struct request_queue *q = bdev_get_queue(bdev);
1575 
1576 	if (q)
1577 		return blk_queue_zone_sectors(q);
1578 
1579 	return 0;
1580 }
1581 
1582 static inline int queue_dma_alignment(struct request_queue *q)
1583 {
1584 	return q ? q->dma_alignment : 511;
1585 }
1586 
1587 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1588 				 unsigned int len)
1589 {
1590 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1591 	return !(addr & alignment) && !(len & alignment);
1592 }
1593 
1594 /* assumes size > 256 */
1595 static inline unsigned int blksize_bits(unsigned int size)
1596 {
1597 	unsigned int bits = 8;
1598 	do {
1599 		bits++;
1600 		size >>= 1;
1601 	} while (size > 256);
1602 	return bits;
1603 }
1604 
1605 static inline unsigned int block_size(struct block_device *bdev)
1606 {
1607 	return bdev->bd_block_size;
1608 }
1609 
1610 static inline bool queue_flush_queueable(struct request_queue *q)
1611 {
1612 	return !test_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
1613 }
1614 
1615 typedef struct {struct page *v;} Sector;
1616 
1617 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1618 
1619 static inline void put_dev_sector(Sector p)
1620 {
1621 	put_page(p.v);
1622 }
1623 
1624 static inline bool __bvec_gap_to_prev(struct request_queue *q,
1625 				struct bio_vec *bprv, unsigned int offset)
1626 {
1627 	return offset ||
1628 		((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
1629 }
1630 
1631 /*
1632  * Check if adding a bio_vec after bprv with offset would create a gap in
1633  * the SG list. Most drivers don't care about this, but some do.
1634  */
1635 static inline bool bvec_gap_to_prev(struct request_queue *q,
1636 				struct bio_vec *bprv, unsigned int offset)
1637 {
1638 	if (!queue_virt_boundary(q))
1639 		return false;
1640 	return __bvec_gap_to_prev(q, bprv, offset);
1641 }
1642 
1643 /*
1644  * Check if the two bvecs from two bios can be merged to one segment.
1645  * If yes, no need to check gap between the two bios since the 1st bio
1646  * and the 1st bvec in the 2nd bio can be handled in one segment.
1647  */
1648 static inline bool bios_segs_mergeable(struct request_queue *q,
1649 		struct bio *prev, struct bio_vec *prev_last_bv,
1650 		struct bio_vec *next_first_bv)
1651 {
1652 	if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv))
1653 		return false;
1654 	if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv))
1655 		return false;
1656 	if (prev->bi_seg_back_size + next_first_bv->bv_len >
1657 			queue_max_segment_size(q))
1658 		return false;
1659 	return true;
1660 }
1661 
1662 static inline bool bio_will_gap(struct request_queue *q,
1663 				struct request *prev_rq,
1664 				struct bio *prev,
1665 				struct bio *next)
1666 {
1667 	if (bio_has_data(prev) && queue_virt_boundary(q)) {
1668 		struct bio_vec pb, nb;
1669 
1670 		/*
1671 		 * don't merge if the 1st bio starts with non-zero
1672 		 * offset, otherwise it is quite difficult to respect
1673 		 * sg gap limit. We work hard to merge a huge number of small
1674 		 * single bios in case of mkfs.
1675 		 */
1676 		if (prev_rq)
1677 			bio_get_first_bvec(prev_rq->bio, &pb);
1678 		else
1679 			bio_get_first_bvec(prev, &pb);
1680 		if (pb.bv_offset)
1681 			return true;
1682 
1683 		/*
1684 		 * We don't need to worry about the situation that the
1685 		 * merged segment ends in unaligned virt boundary:
1686 		 *
1687 		 * - if 'pb' ends aligned, the merged segment ends aligned
1688 		 * - if 'pb' ends unaligned, the next bio must include
1689 		 *   one single bvec of 'nb', otherwise the 'nb' can't
1690 		 *   merge with 'pb'
1691 		 */
1692 		bio_get_last_bvec(prev, &pb);
1693 		bio_get_first_bvec(next, &nb);
1694 
1695 		if (!bios_segs_mergeable(q, prev, &pb, &nb))
1696 			return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
1697 	}
1698 
1699 	return false;
1700 }
1701 
1702 static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
1703 {
1704 	return bio_will_gap(req->q, req, req->biotail, bio);
1705 }
1706 
1707 static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
1708 {
1709 	return bio_will_gap(req->q, NULL, bio, req->bio);
1710 }
1711 
1712 int kblockd_schedule_work(struct work_struct *work);
1713 int kblockd_schedule_work_on(int cpu, struct work_struct *work);
1714 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
1715 int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1716 int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1717 
1718 #ifdef CONFIG_BLK_CGROUP
1719 /*
1720  * This should not be using sched_clock(). A real patch is in progress
1721  * to fix this up, until that is in place we need to disable preemption
1722  * around sched_clock() in this function and set_io_start_time_ns().
1723  */
1724 static inline void set_start_time_ns(struct request *req)
1725 {
1726 	preempt_disable();
1727 	req->start_time_ns = sched_clock();
1728 	preempt_enable();
1729 }
1730 
1731 static inline void set_io_start_time_ns(struct request *req)
1732 {
1733 	preempt_disable();
1734 	req->io_start_time_ns = sched_clock();
1735 	preempt_enable();
1736 }
1737 
1738 static inline uint64_t rq_start_time_ns(struct request *req)
1739 {
1740         return req->start_time_ns;
1741 }
1742 
1743 static inline uint64_t rq_io_start_time_ns(struct request *req)
1744 {
1745         return req->io_start_time_ns;
1746 }
1747 #else
1748 static inline void set_start_time_ns(struct request *req) {}
1749 static inline void set_io_start_time_ns(struct request *req) {}
1750 static inline uint64_t rq_start_time_ns(struct request *req)
1751 {
1752 	return 0;
1753 }
1754 static inline uint64_t rq_io_start_time_ns(struct request *req)
1755 {
1756 	return 0;
1757 }
1758 #endif
1759 
1760 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1761 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1762 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1763 	MODULE_ALIAS("block-major-" __stringify(major) "-*")
1764 
1765 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1766 
1767 enum blk_integrity_flags {
1768 	BLK_INTEGRITY_VERIFY		= 1 << 0,
1769 	BLK_INTEGRITY_GENERATE		= 1 << 1,
1770 	BLK_INTEGRITY_DEVICE_CAPABLE	= 1 << 2,
1771 	BLK_INTEGRITY_IP_CHECKSUM	= 1 << 3,
1772 };
1773 
1774 struct blk_integrity_iter {
1775 	void			*prot_buf;
1776 	void			*data_buf;
1777 	sector_t		seed;
1778 	unsigned int		data_size;
1779 	unsigned short		interval;
1780 	const char		*disk_name;
1781 };
1782 
1783 typedef int (integrity_processing_fn) (struct blk_integrity_iter *);
1784 
1785 struct blk_integrity_profile {
1786 	integrity_processing_fn		*generate_fn;
1787 	integrity_processing_fn		*verify_fn;
1788 	const char			*name;
1789 };
1790 
1791 extern void blk_integrity_register(struct gendisk *, struct blk_integrity *);
1792 extern void blk_integrity_unregister(struct gendisk *);
1793 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1794 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1795 				   struct scatterlist *);
1796 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1797 extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
1798 				   struct request *);
1799 extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
1800 				    struct bio *);
1801 
1802 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1803 {
1804 	struct blk_integrity *bi = &disk->queue->integrity;
1805 
1806 	if (!bi->profile)
1807 		return NULL;
1808 
1809 	return bi;
1810 }
1811 
1812 static inline
1813 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1814 {
1815 	return blk_get_integrity(bdev->bd_disk);
1816 }
1817 
1818 static inline bool blk_integrity_rq(struct request *rq)
1819 {
1820 	return rq->cmd_flags & REQ_INTEGRITY;
1821 }
1822 
1823 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1824 						    unsigned int segs)
1825 {
1826 	q->limits.max_integrity_segments = segs;
1827 }
1828 
1829 static inline unsigned short
1830 queue_max_integrity_segments(struct request_queue *q)
1831 {
1832 	return q->limits.max_integrity_segments;
1833 }
1834 
1835 static inline bool integrity_req_gap_back_merge(struct request *req,
1836 						struct bio *next)
1837 {
1838 	struct bio_integrity_payload *bip = bio_integrity(req->bio);
1839 	struct bio_integrity_payload *bip_next = bio_integrity(next);
1840 
1841 	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1842 				bip_next->bip_vec[0].bv_offset);
1843 }
1844 
1845 static inline bool integrity_req_gap_front_merge(struct request *req,
1846 						 struct bio *bio)
1847 {
1848 	struct bio_integrity_payload *bip = bio_integrity(bio);
1849 	struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
1850 
1851 	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1852 				bip_next->bip_vec[0].bv_offset);
1853 }
1854 
1855 #else /* CONFIG_BLK_DEV_INTEGRITY */
1856 
1857 struct bio;
1858 struct block_device;
1859 struct gendisk;
1860 struct blk_integrity;
1861 
1862 static inline int blk_integrity_rq(struct request *rq)
1863 {
1864 	return 0;
1865 }
1866 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1867 					    struct bio *b)
1868 {
1869 	return 0;
1870 }
1871 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1872 					  struct bio *b,
1873 					  struct scatterlist *s)
1874 {
1875 	return 0;
1876 }
1877 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1878 {
1879 	return NULL;
1880 }
1881 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1882 {
1883 	return NULL;
1884 }
1885 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1886 {
1887 	return 0;
1888 }
1889 static inline void blk_integrity_register(struct gendisk *d,
1890 					 struct blk_integrity *b)
1891 {
1892 }
1893 static inline void blk_integrity_unregister(struct gendisk *d)
1894 {
1895 }
1896 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1897 						    unsigned int segs)
1898 {
1899 }
1900 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1901 {
1902 	return 0;
1903 }
1904 static inline bool blk_integrity_merge_rq(struct request_queue *rq,
1905 					  struct request *r1,
1906 					  struct request *r2)
1907 {
1908 	return true;
1909 }
1910 static inline bool blk_integrity_merge_bio(struct request_queue *rq,
1911 					   struct request *r,
1912 					   struct bio *b)
1913 {
1914 	return true;
1915 }
1916 
1917 static inline bool integrity_req_gap_back_merge(struct request *req,
1918 						struct bio *next)
1919 {
1920 	return false;
1921 }
1922 static inline bool integrity_req_gap_front_merge(struct request *req,
1923 						 struct bio *bio)
1924 {
1925 	return false;
1926 }
1927 
1928 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1929 
1930 struct block_device_operations {
1931 	int (*open) (struct block_device *, fmode_t);
1932 	void (*release) (struct gendisk *, fmode_t);
1933 	int (*rw_page)(struct block_device *, sector_t, struct page *, bool);
1934 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1935 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1936 	unsigned int (*check_events) (struct gendisk *disk,
1937 				      unsigned int clearing);
1938 	/* ->media_changed() is DEPRECATED, use ->check_events() instead */
1939 	int (*media_changed) (struct gendisk *);
1940 	void (*unlock_native_capacity) (struct gendisk *);
1941 	int (*revalidate_disk) (struct gendisk *);
1942 	int (*getgeo)(struct block_device *, struct hd_geometry *);
1943 	/* this callback is with swap_lock and sometimes page table lock held */
1944 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1945 	struct module *owner;
1946 	const struct pr_ops *pr_ops;
1947 };
1948 
1949 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1950 				 unsigned long);
1951 extern int bdev_read_page(struct block_device *, sector_t, struct page *);
1952 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
1953 						struct writeback_control *);
1954 #else /* CONFIG_BLOCK */
1955 
1956 struct block_device;
1957 
1958 /*
1959  * stubs for when the block layer is configured out
1960  */
1961 #define buffer_heads_over_limit 0
1962 
1963 static inline long nr_blockdev_pages(void)
1964 {
1965 	return 0;
1966 }
1967 
1968 struct blk_plug {
1969 };
1970 
1971 static inline void blk_start_plug(struct blk_plug *plug)
1972 {
1973 }
1974 
1975 static inline void blk_finish_plug(struct blk_plug *plug)
1976 {
1977 }
1978 
1979 static inline void blk_flush_plug(struct task_struct *task)
1980 {
1981 }
1982 
1983 static inline void blk_schedule_flush_plug(struct task_struct *task)
1984 {
1985 }
1986 
1987 
1988 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1989 {
1990 	return false;
1991 }
1992 
1993 static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
1994 				     sector_t *error_sector)
1995 {
1996 	return 0;
1997 }
1998 
1999 #endif /* CONFIG_BLOCK */
2000 
2001 #endif
2002