xref: /linux-6.15/include/linux/blkdev.h (revision 27258e44)
1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
3 
4 #ifdef CONFIG_BLOCK
5 
6 #include <linux/sched.h>
7 #include <linux/major.h>
8 #include <linux/genhd.h>
9 #include <linux/list.h>
10 #include <linux/timer.h>
11 #include <linux/workqueue.h>
12 #include <linux/pagemap.h>
13 #include <linux/backing-dev.h>
14 #include <linux/wait.h>
15 #include <linux/mempool.h>
16 #include <linux/bio.h>
17 #include <linux/module.h>
18 #include <linux/stringify.h>
19 #include <linux/gfp.h>
20 #include <linux/bsg.h>
21 #include <linux/smp.h>
22 
23 #include <asm/scatterlist.h>
24 
25 struct scsi_ioctl_command;
26 
27 struct request_queue;
28 struct elevator_queue;
29 struct request_pm_state;
30 struct blk_trace;
31 struct request;
32 struct sg_io_hdr;
33 
34 #define BLKDEV_MIN_RQ	4
35 #define BLKDEV_MAX_RQ	128	/* Default maximum */
36 
37 struct request;
38 typedef void (rq_end_io_fn)(struct request *, int);
39 
40 struct request_list {
41 	/*
42 	 * count[], starved[], and wait[] are indexed by
43 	 * BLK_RW_SYNC/BLK_RW_ASYNC
44 	 */
45 	int count[2];
46 	int starved[2];
47 	int elvpriv;
48 	mempool_t *rq_pool;
49 	wait_queue_head_t wait[2];
50 };
51 
52 /*
53  * request command types
54  */
55 enum rq_cmd_type_bits {
56 	REQ_TYPE_FS		= 1,	/* fs request */
57 	REQ_TYPE_BLOCK_PC,		/* scsi command */
58 	REQ_TYPE_SENSE,			/* sense request */
59 	REQ_TYPE_PM_SUSPEND,		/* suspend request */
60 	REQ_TYPE_PM_RESUME,		/* resume request */
61 	REQ_TYPE_PM_SHUTDOWN,		/* shutdown request */
62 	REQ_TYPE_SPECIAL,		/* driver defined type */
63 	REQ_TYPE_LINUX_BLOCK,		/* generic block layer message */
64 	/*
65 	 * for ATA/ATAPI devices. this really doesn't belong here, ide should
66 	 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
67 	 * private REQ_LB opcodes to differentiate what type of request this is
68 	 */
69 	REQ_TYPE_ATA_TASKFILE,
70 	REQ_TYPE_ATA_PC,
71 };
72 
73 /*
74  * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
75  * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
76  * SCSI cdb.
77  *
78  * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
79  * typically to differentiate REQ_TYPE_SPECIAL requests.
80  *
81  */
82 enum {
83 	REQ_LB_OP_EJECT	= 0x40,		/* eject request */
84 	REQ_LB_OP_FLUSH = 0x41,		/* flush request */
85 	REQ_LB_OP_DISCARD = 0x42,	/* discard sectors */
86 };
87 
88 /*
89  * request type modified bits. first four bits match BIO_RW* bits, important
90  */
91 enum rq_flag_bits {
92 	__REQ_RW,		/* not set, read. set, write */
93 	__REQ_FAILFAST_DEV,	/* no driver retries of device errors */
94 	__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
95 	__REQ_FAILFAST_DRIVER,	/* no driver retries of driver errors */
96 	/* above flags must match BIO_RW_* */
97 	__REQ_DISCARD,		/* request to discard sectors */
98 	__REQ_SORTED,		/* elevator knows about this request */
99 	__REQ_SOFTBARRIER,	/* may not be passed by ioscheduler */
100 	__REQ_HARDBARRIER,	/* may not be passed by drive either */
101 	__REQ_FUA,		/* forced unit access */
102 	__REQ_NOMERGE,		/* don't touch this for merging */
103 	__REQ_STARTED,		/* drive already may have started this one */
104 	__REQ_DONTPREP,		/* don't call prep for this one */
105 	__REQ_QUEUED,		/* uses queueing */
106 	__REQ_ELVPRIV,		/* elevator private data attached */
107 	__REQ_FAILED,		/* set if the request failed */
108 	__REQ_QUIET,		/* don't worry about errors */
109 	__REQ_PREEMPT,		/* set for "ide_preempt" requests */
110 	__REQ_ORDERED_COLOR,	/* is before or after barrier */
111 	__REQ_RW_SYNC,		/* request is sync (sync write or read) */
112 	__REQ_ALLOCED,		/* request came from our alloc pool */
113 	__REQ_RW_META,		/* metadata io request */
114 	__REQ_COPY_USER,	/* contains copies of user pages */
115 	__REQ_INTEGRITY,	/* integrity metadata has been remapped */
116 	__REQ_NOIDLE,		/* Don't anticipate more IO after this one */
117 	__REQ_IO_STAT,		/* account I/O stat */
118 	__REQ_MIXED_MERGE,	/* merge of different types, fail separately */
119 	__REQ_NR_BITS,		/* stops here */
120 };
121 
122 #define REQ_RW		(1 << __REQ_RW)
123 #define REQ_FAILFAST_DEV	(1 << __REQ_FAILFAST_DEV)
124 #define REQ_FAILFAST_TRANSPORT	(1 << __REQ_FAILFAST_TRANSPORT)
125 #define REQ_FAILFAST_DRIVER	(1 << __REQ_FAILFAST_DRIVER)
126 #define REQ_DISCARD	(1 << __REQ_DISCARD)
127 #define REQ_SORTED	(1 << __REQ_SORTED)
128 #define REQ_SOFTBARRIER	(1 << __REQ_SOFTBARRIER)
129 #define REQ_HARDBARRIER	(1 << __REQ_HARDBARRIER)
130 #define REQ_FUA		(1 << __REQ_FUA)
131 #define REQ_NOMERGE	(1 << __REQ_NOMERGE)
132 #define REQ_STARTED	(1 << __REQ_STARTED)
133 #define REQ_DONTPREP	(1 << __REQ_DONTPREP)
134 #define REQ_QUEUED	(1 << __REQ_QUEUED)
135 #define REQ_ELVPRIV	(1 << __REQ_ELVPRIV)
136 #define REQ_FAILED	(1 << __REQ_FAILED)
137 #define REQ_QUIET	(1 << __REQ_QUIET)
138 #define REQ_PREEMPT	(1 << __REQ_PREEMPT)
139 #define REQ_ORDERED_COLOR	(1 << __REQ_ORDERED_COLOR)
140 #define REQ_RW_SYNC	(1 << __REQ_RW_SYNC)
141 #define REQ_ALLOCED	(1 << __REQ_ALLOCED)
142 #define REQ_RW_META	(1 << __REQ_RW_META)
143 #define REQ_COPY_USER	(1 << __REQ_COPY_USER)
144 #define REQ_INTEGRITY	(1 << __REQ_INTEGRITY)
145 #define REQ_NOIDLE	(1 << __REQ_NOIDLE)
146 #define REQ_IO_STAT	(1 << __REQ_IO_STAT)
147 #define REQ_MIXED_MERGE	(1 << __REQ_MIXED_MERGE)
148 
149 #define REQ_FAILFAST_MASK	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | \
150 				 REQ_FAILFAST_DRIVER)
151 
152 #define BLK_MAX_CDB	16
153 
154 /*
155  * try to put the fields that are referenced together in the same cacheline.
156  * if you modify this structure, be sure to check block/blk-core.c:rq_init()
157  * as well!
158  */
159 struct request {
160 	struct list_head queuelist;
161 	struct call_single_data csd;
162 	int cpu;
163 
164 	struct request_queue *q;
165 
166 	unsigned int cmd_flags;
167 	enum rq_cmd_type_bits cmd_type;
168 	unsigned long atomic_flags;
169 
170 	/* the following two fields are internal, NEVER access directly */
171 	sector_t __sector;		/* sector cursor */
172 	unsigned int __data_len;	/* total data len */
173 
174 	struct bio *bio;
175 	struct bio *biotail;
176 
177 	struct hlist_node hash;	/* merge hash */
178 	/*
179 	 * The rb_node is only used inside the io scheduler, requests
180 	 * are pruned when moved to the dispatch queue. So let the
181 	 * completion_data share space with the rb_node.
182 	 */
183 	union {
184 		struct rb_node rb_node;	/* sort/lookup */
185 		void *completion_data;
186 	};
187 
188 	/*
189 	 * two pointers are available for the IO schedulers, if they need
190 	 * more they have to dynamically allocate it.
191 	 */
192 	void *elevator_private;
193 	void *elevator_private2;
194 
195 	struct gendisk *rq_disk;
196 	unsigned long start_time;
197 
198 	/* Number of scatter-gather DMA addr+len pairs after
199 	 * physical address coalescing is performed.
200 	 */
201 	unsigned short nr_phys_segments;
202 
203 	unsigned short ioprio;
204 
205 	void *special;		/* opaque pointer available for LLD use */
206 	char *buffer;		/* kaddr of the current segment if available */
207 
208 	int tag;
209 	int errors;
210 
211 	int ref_count;
212 
213 	/*
214 	 * when request is used as a packet command carrier
215 	 */
216 	unsigned short cmd_len;
217 	unsigned char __cmd[BLK_MAX_CDB];
218 	unsigned char *cmd;
219 
220 	unsigned int extra_len;	/* length of alignment and padding */
221 	unsigned int sense_len;
222 	unsigned int resid_len;	/* residual count */
223 	void *sense;
224 
225 	unsigned long deadline;
226 	struct list_head timeout_list;
227 	unsigned int timeout;
228 	int retries;
229 
230 	/*
231 	 * completion callback.
232 	 */
233 	rq_end_io_fn *end_io;
234 	void *end_io_data;
235 
236 	/* for bidi */
237 	struct request *next_rq;
238 };
239 
240 static inline unsigned short req_get_ioprio(struct request *req)
241 {
242 	return req->ioprio;
243 }
244 
245 /*
246  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
247  * requests. Some step values could eventually be made generic.
248  */
249 struct request_pm_state
250 {
251 	/* PM state machine step value, currently driver specific */
252 	int	pm_step;
253 	/* requested PM state value (S1, S2, S3, S4, ...) */
254 	u32	pm_state;
255 	void*	data;		/* for driver use */
256 };
257 
258 #include <linux/elevator.h>
259 
260 typedef void (request_fn_proc) (struct request_queue *q);
261 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
262 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
263 typedef void (unplug_fn) (struct request_queue *);
264 typedef int (prepare_discard_fn) (struct request_queue *, struct request *);
265 
266 struct bio_vec;
267 struct bvec_merge_data {
268 	struct block_device *bi_bdev;
269 	sector_t bi_sector;
270 	unsigned bi_size;
271 	unsigned long bi_rw;
272 };
273 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
274 			     struct bio_vec *);
275 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
276 typedef void (softirq_done_fn)(struct request *);
277 typedef int (dma_drain_needed_fn)(struct request *);
278 typedef int (lld_busy_fn) (struct request_queue *q);
279 
280 enum blk_eh_timer_return {
281 	BLK_EH_NOT_HANDLED,
282 	BLK_EH_HANDLED,
283 	BLK_EH_RESET_TIMER,
284 };
285 
286 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
287 
288 enum blk_queue_state {
289 	Queue_down,
290 	Queue_up,
291 };
292 
293 struct blk_queue_tag {
294 	struct request **tag_index;	/* map of busy tags */
295 	unsigned long *tag_map;		/* bit map of free/busy tags */
296 	int busy;			/* current depth */
297 	int max_depth;			/* what we will send to device */
298 	int real_max_depth;		/* what the array can hold */
299 	atomic_t refcnt;		/* map can be shared */
300 };
301 
302 #define BLK_SCSI_MAX_CMDS	(256)
303 #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
304 
305 struct queue_limits {
306 	unsigned long		bounce_pfn;
307 	unsigned long		seg_boundary_mask;
308 
309 	unsigned int		max_hw_sectors;
310 	unsigned int		max_sectors;
311 	unsigned int		max_segment_size;
312 	unsigned int		physical_block_size;
313 	unsigned int		alignment_offset;
314 	unsigned int		io_min;
315 	unsigned int		io_opt;
316 
317 	unsigned short		logical_block_size;
318 	unsigned short		max_hw_segments;
319 	unsigned short		max_phys_segments;
320 
321 	unsigned char		misaligned;
322 	unsigned char		no_cluster;
323 };
324 
325 struct request_queue
326 {
327 	/*
328 	 * Together with queue_head for cacheline sharing
329 	 */
330 	struct list_head	queue_head;
331 	struct request		*last_merge;
332 	struct elevator_queue	*elevator;
333 
334 	/*
335 	 * the queue request freelist, one for reads and one for writes
336 	 */
337 	struct request_list	rq;
338 
339 	request_fn_proc		*request_fn;
340 	make_request_fn		*make_request_fn;
341 	prep_rq_fn		*prep_rq_fn;
342 	unplug_fn		*unplug_fn;
343 	prepare_discard_fn	*prepare_discard_fn;
344 	merge_bvec_fn		*merge_bvec_fn;
345 	prepare_flush_fn	*prepare_flush_fn;
346 	softirq_done_fn		*softirq_done_fn;
347 	rq_timed_out_fn		*rq_timed_out_fn;
348 	dma_drain_needed_fn	*dma_drain_needed;
349 	lld_busy_fn		*lld_busy_fn;
350 
351 	/*
352 	 * Dispatch queue sorting
353 	 */
354 	sector_t		end_sector;
355 	struct request		*boundary_rq;
356 
357 	/*
358 	 * Auto-unplugging state
359 	 */
360 	struct timer_list	unplug_timer;
361 	int			unplug_thresh;	/* After this many requests */
362 	unsigned long		unplug_delay;	/* After this many jiffies */
363 	struct work_struct	unplug_work;
364 
365 	struct backing_dev_info	backing_dev_info;
366 
367 	/*
368 	 * The queue owner gets to use this for whatever they like.
369 	 * ll_rw_blk doesn't touch it.
370 	 */
371 	void			*queuedata;
372 
373 	/*
374 	 * queue needs bounce pages for pages above this limit
375 	 */
376 	gfp_t			bounce_gfp;
377 
378 	/*
379 	 * various queue flags, see QUEUE_* below
380 	 */
381 	unsigned long		queue_flags;
382 
383 	/*
384 	 * protects queue structures from reentrancy. ->__queue_lock should
385 	 * _never_ be used directly, it is queue private. always use
386 	 * ->queue_lock.
387 	 */
388 	spinlock_t		__queue_lock;
389 	spinlock_t		*queue_lock;
390 
391 	/*
392 	 * queue kobject
393 	 */
394 	struct kobject kobj;
395 
396 	/*
397 	 * queue settings
398 	 */
399 	unsigned long		nr_requests;	/* Max # of requests */
400 	unsigned int		nr_congestion_on;
401 	unsigned int		nr_congestion_off;
402 	unsigned int		nr_batching;
403 
404 	void			*dma_drain_buffer;
405 	unsigned int		dma_drain_size;
406 	unsigned int		dma_pad_mask;
407 	unsigned int		dma_alignment;
408 
409 	struct blk_queue_tag	*queue_tags;
410 	struct list_head	tag_busy_list;
411 
412 	unsigned int		nr_sorted;
413 	unsigned int		in_flight[2];
414 
415 	unsigned int		rq_timeout;
416 	struct timer_list	timeout;
417 	struct list_head	timeout_list;
418 
419 	struct queue_limits	limits;
420 
421 	/*
422 	 * sg stuff
423 	 */
424 	unsigned int		sg_timeout;
425 	unsigned int		sg_reserved_size;
426 	int			node;
427 #ifdef CONFIG_BLK_DEV_IO_TRACE
428 	struct blk_trace	*blk_trace;
429 #endif
430 	/*
431 	 * reserved for flush operations
432 	 */
433 	unsigned int		ordered, next_ordered, ordseq;
434 	int			orderr, ordcolor;
435 	struct request		pre_flush_rq, bar_rq, post_flush_rq;
436 	struct request		*orig_bar_rq;
437 
438 	struct mutex		sysfs_lock;
439 
440 #if defined(CONFIG_BLK_DEV_BSG)
441 	struct bsg_class_device bsg_dev;
442 #endif
443 };
444 
445 #define QUEUE_FLAG_CLUSTER	0	/* cluster several segments into 1 */
446 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
447 #define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
448 #define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
449 #define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
450 #define QUEUE_FLAG_DEAD		5	/* queue being torn down */
451 #define QUEUE_FLAG_REENTER	6	/* Re-entrancy avoidance */
452 #define QUEUE_FLAG_PLUGGED	7	/* queue is plugged */
453 #define QUEUE_FLAG_ELVSWITCH	8	/* don't use elevator, just do FIFO */
454 #define QUEUE_FLAG_BIDI		9	/* queue supports bidi requests */
455 #define QUEUE_FLAG_NOMERGES    10	/* disable merge attempts */
456 #define QUEUE_FLAG_SAME_COMP   11	/* force complete on same CPU */
457 #define QUEUE_FLAG_FAIL_IO     12	/* fake timeout */
458 #define QUEUE_FLAG_STACKABLE   13	/* supports request stacking */
459 #define QUEUE_FLAG_NONROT      14	/* non-rotational device (SSD) */
460 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
461 #define QUEUE_FLAG_IO_STAT     15	/* do IO stats */
462 #define QUEUE_FLAG_CQ	       16	/* hardware does queuing */
463 
464 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
465 				 (1 << QUEUE_FLAG_CLUSTER) |		\
466 				 (1 << QUEUE_FLAG_STACKABLE)	|	\
467 				 (1 << QUEUE_FLAG_SAME_COMP))
468 
469 static inline int queue_is_locked(struct request_queue *q)
470 {
471 #ifdef CONFIG_SMP
472 	spinlock_t *lock = q->queue_lock;
473 	return lock && spin_is_locked(lock);
474 #else
475 	return 1;
476 #endif
477 }
478 
479 static inline void queue_flag_set_unlocked(unsigned int flag,
480 					   struct request_queue *q)
481 {
482 	__set_bit(flag, &q->queue_flags);
483 }
484 
485 static inline int queue_flag_test_and_clear(unsigned int flag,
486 					    struct request_queue *q)
487 {
488 	WARN_ON_ONCE(!queue_is_locked(q));
489 
490 	if (test_bit(flag, &q->queue_flags)) {
491 		__clear_bit(flag, &q->queue_flags);
492 		return 1;
493 	}
494 
495 	return 0;
496 }
497 
498 static inline int queue_flag_test_and_set(unsigned int flag,
499 					  struct request_queue *q)
500 {
501 	WARN_ON_ONCE(!queue_is_locked(q));
502 
503 	if (!test_bit(flag, &q->queue_flags)) {
504 		__set_bit(flag, &q->queue_flags);
505 		return 0;
506 	}
507 
508 	return 1;
509 }
510 
511 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
512 {
513 	WARN_ON_ONCE(!queue_is_locked(q));
514 	__set_bit(flag, &q->queue_flags);
515 }
516 
517 static inline void queue_flag_clear_unlocked(unsigned int flag,
518 					     struct request_queue *q)
519 {
520 	__clear_bit(flag, &q->queue_flags);
521 }
522 
523 static inline int queue_in_flight(struct request_queue *q)
524 {
525 	return q->in_flight[0] + q->in_flight[1];
526 }
527 
528 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
529 {
530 	WARN_ON_ONCE(!queue_is_locked(q));
531 	__clear_bit(flag, &q->queue_flags);
532 }
533 
534 enum {
535 	/*
536 	 * Hardbarrier is supported with one of the following methods.
537 	 *
538 	 * NONE		: hardbarrier unsupported
539 	 * DRAIN	: ordering by draining is enough
540 	 * DRAIN_FLUSH	: ordering by draining w/ pre and post flushes
541 	 * DRAIN_FUA	: ordering by draining w/ pre flush and FUA write
542 	 * TAG		: ordering by tag is enough
543 	 * TAG_FLUSH	: ordering by tag w/ pre and post flushes
544 	 * TAG_FUA	: ordering by tag w/ pre flush and FUA write
545 	 */
546 	QUEUE_ORDERED_BY_DRAIN		= 0x01,
547 	QUEUE_ORDERED_BY_TAG		= 0x02,
548 	QUEUE_ORDERED_DO_PREFLUSH	= 0x10,
549 	QUEUE_ORDERED_DO_BAR		= 0x20,
550 	QUEUE_ORDERED_DO_POSTFLUSH	= 0x40,
551 	QUEUE_ORDERED_DO_FUA		= 0x80,
552 
553 	QUEUE_ORDERED_NONE		= 0x00,
554 
555 	QUEUE_ORDERED_DRAIN		= QUEUE_ORDERED_BY_DRAIN |
556 					  QUEUE_ORDERED_DO_BAR,
557 	QUEUE_ORDERED_DRAIN_FLUSH	= QUEUE_ORDERED_DRAIN |
558 					  QUEUE_ORDERED_DO_PREFLUSH |
559 					  QUEUE_ORDERED_DO_POSTFLUSH,
560 	QUEUE_ORDERED_DRAIN_FUA		= QUEUE_ORDERED_DRAIN |
561 					  QUEUE_ORDERED_DO_PREFLUSH |
562 					  QUEUE_ORDERED_DO_FUA,
563 
564 	QUEUE_ORDERED_TAG		= QUEUE_ORDERED_BY_TAG |
565 					  QUEUE_ORDERED_DO_BAR,
566 	QUEUE_ORDERED_TAG_FLUSH		= QUEUE_ORDERED_TAG |
567 					  QUEUE_ORDERED_DO_PREFLUSH |
568 					  QUEUE_ORDERED_DO_POSTFLUSH,
569 	QUEUE_ORDERED_TAG_FUA		= QUEUE_ORDERED_TAG |
570 					  QUEUE_ORDERED_DO_PREFLUSH |
571 					  QUEUE_ORDERED_DO_FUA,
572 
573 	/*
574 	 * Ordered operation sequence
575 	 */
576 	QUEUE_ORDSEQ_STARTED	= 0x01,	/* flushing in progress */
577 	QUEUE_ORDSEQ_DRAIN	= 0x02,	/* waiting for the queue to be drained */
578 	QUEUE_ORDSEQ_PREFLUSH	= 0x04,	/* pre-flushing in progress */
579 	QUEUE_ORDSEQ_BAR	= 0x08,	/* original barrier req in progress */
580 	QUEUE_ORDSEQ_POSTFLUSH	= 0x10,	/* post-flushing in progress */
581 	QUEUE_ORDSEQ_DONE	= 0x20,
582 };
583 
584 #define blk_queue_plugged(q)	test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
585 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
586 #define blk_queue_queuing(q)	test_bit(QUEUE_FLAG_CQ, &(q)->queue_flags)
587 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
588 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
589 #define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
590 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
591 #define blk_queue_flushing(q)	((q)->ordseq)
592 #define blk_queue_stackable(q)	\
593 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
594 
595 #define blk_fs_request(rq)	((rq)->cmd_type == REQ_TYPE_FS)
596 #define blk_pc_request(rq)	((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
597 #define blk_special_request(rq)	((rq)->cmd_type == REQ_TYPE_SPECIAL)
598 #define blk_sense_request(rq)	((rq)->cmd_type == REQ_TYPE_SENSE)
599 
600 #define blk_failfast_dev(rq)	((rq)->cmd_flags & REQ_FAILFAST_DEV)
601 #define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
602 #define blk_failfast_driver(rq)	((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
603 #define blk_noretry_request(rq)	(blk_failfast_dev(rq) ||	\
604 				 blk_failfast_transport(rq) ||	\
605 				 blk_failfast_driver(rq))
606 #define blk_rq_started(rq)	((rq)->cmd_flags & REQ_STARTED)
607 #define blk_rq_io_stat(rq)	((rq)->cmd_flags & REQ_IO_STAT)
608 #define blk_rq_quiet(rq)	((rq)->cmd_flags & REQ_QUIET)
609 
610 #define blk_account_rq(rq)	(blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))
611 
612 #define blk_pm_suspend_request(rq)	((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
613 #define blk_pm_resume_request(rq)	((rq)->cmd_type == REQ_TYPE_PM_RESUME)
614 #define blk_pm_request(rq)	\
615 	(blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
616 
617 #define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
618 #define blk_sorted_rq(rq)	((rq)->cmd_flags & REQ_SORTED)
619 #define blk_barrier_rq(rq)	((rq)->cmd_flags & REQ_HARDBARRIER)
620 #define blk_fua_rq(rq)		((rq)->cmd_flags & REQ_FUA)
621 #define blk_discard_rq(rq)	((rq)->cmd_flags & REQ_DISCARD)
622 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
623 /* rq->queuelist of dequeued request must be list_empty() */
624 #define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
625 
626 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
627 
628 #define rq_data_dir(rq)		((rq)->cmd_flags & 1)
629 
630 /*
631  * We regard a request as sync, if either a read or a sync write
632  */
633 static inline bool rw_is_sync(unsigned int rw_flags)
634 {
635 	return !(rw_flags & REQ_RW) || (rw_flags & REQ_RW_SYNC);
636 }
637 
638 static inline bool rq_is_sync(struct request *rq)
639 {
640 	return rw_is_sync(rq->cmd_flags);
641 }
642 
643 #define rq_is_meta(rq)		((rq)->cmd_flags & REQ_RW_META)
644 #define rq_noidle(rq)		((rq)->cmd_flags & REQ_NOIDLE)
645 
646 static inline int blk_queue_full(struct request_queue *q, int sync)
647 {
648 	if (sync)
649 		return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
650 	return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
651 }
652 
653 static inline void blk_set_queue_full(struct request_queue *q, int sync)
654 {
655 	if (sync)
656 		queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
657 	else
658 		queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
659 }
660 
661 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
662 {
663 	if (sync)
664 		queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
665 	else
666 		queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
667 }
668 
669 
670 /*
671  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
672  * it already be started by driver.
673  */
674 #define RQ_NOMERGE_FLAGS	\
675 	(REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
676 #define rq_mergeable(rq)	\
677 	(!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
678 	 (blk_discard_rq(rq) || blk_fs_request((rq))))
679 
680 /*
681  * q->prep_rq_fn return values
682  */
683 #define BLKPREP_OK		0	/* serve it */
684 #define BLKPREP_KILL		1	/* fatal error, kill */
685 #define BLKPREP_DEFER		2	/* leave on queue */
686 
687 extern unsigned long blk_max_low_pfn, blk_max_pfn;
688 
689 /*
690  * standard bounce addresses:
691  *
692  * BLK_BOUNCE_HIGH	: bounce all highmem pages
693  * BLK_BOUNCE_ANY	: don't bounce anything
694  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
695  */
696 
697 #if BITS_PER_LONG == 32
698 #define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
699 #else
700 #define BLK_BOUNCE_HIGH		-1ULL
701 #endif
702 #define BLK_BOUNCE_ANY		(-1ULL)
703 #define BLK_BOUNCE_ISA		(ISA_DMA_THRESHOLD)
704 
705 /*
706  * default timeout for SG_IO if none specified
707  */
708 #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
709 #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
710 
711 #ifdef CONFIG_BOUNCE
712 extern int init_emergency_isa_pool(void);
713 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
714 #else
715 static inline int init_emergency_isa_pool(void)
716 {
717 	return 0;
718 }
719 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
720 {
721 }
722 #endif /* CONFIG_MMU */
723 
724 struct rq_map_data {
725 	struct page **pages;
726 	int page_order;
727 	int nr_entries;
728 	unsigned long offset;
729 	int null_mapped;
730 	int from_user;
731 };
732 
733 struct req_iterator {
734 	int i;
735 	struct bio *bio;
736 };
737 
738 /* This should not be used directly - use rq_for_each_segment */
739 #define for_each_bio(_bio)		\
740 	for (; _bio; _bio = _bio->bi_next)
741 #define __rq_for_each_bio(_bio, rq)	\
742 	if ((rq->bio))			\
743 		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
744 
745 #define rq_for_each_segment(bvl, _rq, _iter)			\
746 	__rq_for_each_bio(_iter.bio, _rq)			\
747 		bio_for_each_segment(bvl, _iter.bio, _iter.i)
748 
749 #define rq_iter_last(rq, _iter)					\
750 		(_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
751 
752 extern int blk_register_queue(struct gendisk *disk);
753 extern void blk_unregister_queue(struct gendisk *disk);
754 extern void register_disk(struct gendisk *dev);
755 extern void generic_make_request(struct bio *bio);
756 extern void blk_rq_init(struct request_queue *q, struct request *rq);
757 extern void blk_put_request(struct request *);
758 extern void __blk_put_request(struct request_queue *, struct request *);
759 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
760 extern struct request *blk_make_request(struct request_queue *, struct bio *,
761 					gfp_t);
762 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
763 extern void blk_requeue_request(struct request_queue *, struct request *);
764 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
765 extern int blk_lld_busy(struct request_queue *q);
766 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
767 			     struct bio_set *bs, gfp_t gfp_mask,
768 			     int (*bio_ctr)(struct bio *, struct bio *, void *),
769 			     void *data);
770 extern void blk_rq_unprep_clone(struct request *rq);
771 extern int blk_insert_cloned_request(struct request_queue *q,
772 				     struct request *rq);
773 extern void blk_plug_device(struct request_queue *);
774 extern void blk_plug_device_unlocked(struct request_queue *);
775 extern int blk_remove_plug(struct request_queue *);
776 extern void blk_recount_segments(struct request_queue *, struct bio *);
777 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
778 			  unsigned int, void __user *);
779 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
780 			 struct scsi_ioctl_command __user *);
781 
782 /*
783  * A queue has just exitted congestion.  Note this in the global counter of
784  * congested queues, and wake up anyone who was waiting for requests to be
785  * put back.
786  */
787 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
788 {
789 	clear_bdi_congested(&q->backing_dev_info, sync);
790 }
791 
792 /*
793  * A queue has just entered congestion.  Flag that in the queue's VM-visible
794  * state flags and increment the global gounter of congested queues.
795  */
796 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
797 {
798 	set_bdi_congested(&q->backing_dev_info, sync);
799 }
800 
801 extern void blk_start_queue(struct request_queue *q);
802 extern void blk_stop_queue(struct request_queue *q);
803 extern void blk_sync_queue(struct request_queue *q);
804 extern void __blk_stop_queue(struct request_queue *q);
805 extern void __blk_run_queue(struct request_queue *);
806 extern void blk_run_queue(struct request_queue *);
807 extern int blk_rq_map_user(struct request_queue *, struct request *,
808 			   struct rq_map_data *, void __user *, unsigned long,
809 			   gfp_t);
810 extern int blk_rq_unmap_user(struct bio *);
811 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
812 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
813 			       struct rq_map_data *, struct sg_iovec *, int,
814 			       unsigned int, gfp_t);
815 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
816 			  struct request *, int);
817 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
818 				  struct request *, int, rq_end_io_fn *);
819 extern void blk_unplug(struct request_queue *q);
820 
821 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
822 {
823 	return bdev->bd_disk->queue;
824 }
825 
826 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
827 				       struct page *page)
828 {
829 	if (bdi && bdi->unplug_io_fn)
830 		bdi->unplug_io_fn(bdi, page);
831 }
832 
833 static inline void blk_run_address_space(struct address_space *mapping)
834 {
835 	if (mapping)
836 		blk_run_backing_dev(mapping->backing_dev_info, NULL);
837 }
838 
839 /*
840  * blk_rq_pos()			: the current sector
841  * blk_rq_bytes()		: bytes left in the entire request
842  * blk_rq_cur_bytes()		: bytes left in the current segment
843  * blk_rq_err_bytes()		: bytes left till the next error boundary
844  * blk_rq_sectors()		: sectors left in the entire request
845  * blk_rq_cur_sectors()		: sectors left in the current segment
846  * blk_rq_err_sectors()		: sectors left till the next error boundary
847  */
848 static inline sector_t blk_rq_pos(const struct request *rq)
849 {
850 	return rq->__sector;
851 }
852 
853 static inline unsigned int blk_rq_bytes(const struct request *rq)
854 {
855 	return rq->__data_len;
856 }
857 
858 static inline int blk_rq_cur_bytes(const struct request *rq)
859 {
860 	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
861 }
862 
863 extern unsigned int blk_rq_err_bytes(const struct request *rq);
864 
865 static inline unsigned int blk_rq_sectors(const struct request *rq)
866 {
867 	return blk_rq_bytes(rq) >> 9;
868 }
869 
870 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
871 {
872 	return blk_rq_cur_bytes(rq) >> 9;
873 }
874 
875 static inline unsigned int blk_rq_err_sectors(const struct request *rq)
876 {
877 	return blk_rq_err_bytes(rq) >> 9;
878 }
879 
880 /*
881  * Request issue related functions.
882  */
883 extern struct request *blk_peek_request(struct request_queue *q);
884 extern void blk_start_request(struct request *rq);
885 extern struct request *blk_fetch_request(struct request_queue *q);
886 
887 /*
888  * Request completion related functions.
889  *
890  * blk_update_request() completes given number of bytes and updates
891  * the request without completing it.
892  *
893  * blk_end_request() and friends.  __blk_end_request() must be called
894  * with the request queue spinlock acquired.
895  *
896  * Several drivers define their own end_request and call
897  * blk_end_request() for parts of the original function.
898  * This prevents code duplication in drivers.
899  */
900 extern bool blk_update_request(struct request *rq, int error,
901 			       unsigned int nr_bytes);
902 extern bool blk_end_request(struct request *rq, int error,
903 			    unsigned int nr_bytes);
904 extern void blk_end_request_all(struct request *rq, int error);
905 extern bool blk_end_request_cur(struct request *rq, int error);
906 extern bool blk_end_request_err(struct request *rq, int error);
907 extern bool __blk_end_request(struct request *rq, int error,
908 			      unsigned int nr_bytes);
909 extern void __blk_end_request_all(struct request *rq, int error);
910 extern bool __blk_end_request_cur(struct request *rq, int error);
911 extern bool __blk_end_request_err(struct request *rq, int error);
912 
913 extern void blk_complete_request(struct request *);
914 extern void __blk_complete_request(struct request *);
915 extern void blk_abort_request(struct request *);
916 extern void blk_abort_queue(struct request_queue *);
917 
918 /*
919  * Access functions for manipulating queue properties
920  */
921 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
922 					spinlock_t *lock, int node_id);
923 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
924 extern void blk_cleanup_queue(struct request_queue *);
925 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
926 extern void blk_queue_bounce_limit(struct request_queue *, u64);
927 extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
928 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
929 extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
930 extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
931 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
932 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
933 extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
934 extern void blk_queue_alignment_offset(struct request_queue *q,
935 				       unsigned int alignment);
936 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
937 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
938 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
939 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
940 extern void blk_set_default_limits(struct queue_limits *lim);
941 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
942 			    sector_t offset);
943 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
944 			      sector_t offset);
945 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
946 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
947 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
948 extern int blk_queue_dma_drain(struct request_queue *q,
949 			       dma_drain_needed_fn *dma_drain_needed,
950 			       void *buf, unsigned int size);
951 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
952 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
953 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
954 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
955 extern void blk_queue_dma_alignment(struct request_queue *, int);
956 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
957 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
958 extern void blk_queue_set_discard(struct request_queue *, prepare_discard_fn *);
959 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
960 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
961 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
962 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
963 extern bool blk_do_ordered(struct request_queue *, struct request **);
964 extern unsigned blk_ordered_cur_seq(struct request_queue *);
965 extern unsigned blk_ordered_req_seq(struct request *);
966 extern bool blk_ordered_complete_seq(struct request_queue *, unsigned, int);
967 
968 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
969 extern void blk_dump_rq_flags(struct request *, char *);
970 extern void generic_unplug_device(struct request_queue *);
971 extern long nr_blockdev_pages(void);
972 
973 int blk_get_queue(struct request_queue *);
974 struct request_queue *blk_alloc_queue(gfp_t);
975 struct request_queue *blk_alloc_queue_node(gfp_t, int);
976 extern void blk_put_queue(struct request_queue *);
977 
978 /*
979  * tag stuff
980  */
981 #define blk_rq_tagged(rq)		((rq)->cmd_flags & REQ_QUEUED)
982 extern int blk_queue_start_tag(struct request_queue *, struct request *);
983 extern struct request *blk_queue_find_tag(struct request_queue *, int);
984 extern void blk_queue_end_tag(struct request_queue *, struct request *);
985 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
986 extern void blk_queue_free_tags(struct request_queue *);
987 extern int blk_queue_resize_tags(struct request_queue *, int);
988 extern void blk_queue_invalidate_tags(struct request_queue *);
989 extern struct blk_queue_tag *blk_init_tags(int);
990 extern void blk_free_tags(struct blk_queue_tag *);
991 
992 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
993 						int tag)
994 {
995 	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
996 		return NULL;
997 	return bqt->tag_index[tag];
998 }
999 
1000 extern int blkdev_issue_flush(struct block_device *, sector_t *);
1001 #define DISCARD_FL_WAIT		0x01	/* wait for completion */
1002 #define DISCARD_FL_BARRIER	0x02	/* issue DISCARD_BARRIER request */
1003 extern int blkdev_issue_discard(struct block_device *, sector_t sector,
1004 		sector_t nr_sects, gfp_t, int flags);
1005 
1006 static inline int sb_issue_discard(struct super_block *sb,
1007 				   sector_t block, sector_t nr_blocks)
1008 {
1009 	block <<= (sb->s_blocksize_bits - 9);
1010 	nr_blocks <<= (sb->s_blocksize_bits - 9);
1011 	return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL,
1012 				    DISCARD_FL_BARRIER);
1013 }
1014 
1015 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1016 
1017 #define MAX_PHYS_SEGMENTS 128
1018 #define MAX_HW_SEGMENTS 128
1019 #define SAFE_MAX_SECTORS 255
1020 #define BLK_DEF_MAX_SECTORS 1024
1021 
1022 #define MAX_SEGMENT_SIZE	65536
1023 
1024 #define BLK_SEG_BOUNDARY_MASK	0xFFFFFFFFUL
1025 
1026 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1027 
1028 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1029 {
1030 	return q->limits.bounce_pfn;
1031 }
1032 
1033 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1034 {
1035 	return q->limits.seg_boundary_mask;
1036 }
1037 
1038 static inline unsigned int queue_max_sectors(struct request_queue *q)
1039 {
1040 	return q->limits.max_sectors;
1041 }
1042 
1043 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1044 {
1045 	return q->limits.max_hw_sectors;
1046 }
1047 
1048 static inline unsigned short queue_max_hw_segments(struct request_queue *q)
1049 {
1050 	return q->limits.max_hw_segments;
1051 }
1052 
1053 static inline unsigned short queue_max_phys_segments(struct request_queue *q)
1054 {
1055 	return q->limits.max_phys_segments;
1056 }
1057 
1058 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1059 {
1060 	return q->limits.max_segment_size;
1061 }
1062 
1063 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1064 {
1065 	int retval = 512;
1066 
1067 	if (q && q->limits.logical_block_size)
1068 		retval = q->limits.logical_block_size;
1069 
1070 	return retval;
1071 }
1072 
1073 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1074 {
1075 	return queue_logical_block_size(bdev_get_queue(bdev));
1076 }
1077 
1078 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1079 {
1080 	return q->limits.physical_block_size;
1081 }
1082 
1083 static inline unsigned int queue_io_min(struct request_queue *q)
1084 {
1085 	return q->limits.io_min;
1086 }
1087 
1088 static inline unsigned int queue_io_opt(struct request_queue *q)
1089 {
1090 	return q->limits.io_opt;
1091 }
1092 
1093 static inline int queue_alignment_offset(struct request_queue *q)
1094 {
1095 	if (q && q->limits.misaligned)
1096 		return -1;
1097 
1098 	if (q && q->limits.alignment_offset)
1099 		return q->limits.alignment_offset;
1100 
1101 	return 0;
1102 }
1103 
1104 static inline int queue_sector_alignment_offset(struct request_queue *q,
1105 						sector_t sector)
1106 {
1107 	return ((sector << 9) - q->limits.alignment_offset)
1108 		& (q->limits.io_min - 1);
1109 }
1110 
1111 static inline int queue_dma_alignment(struct request_queue *q)
1112 {
1113 	return q ? q->dma_alignment : 511;
1114 }
1115 
1116 static inline int blk_rq_aligned(struct request_queue *q, void *addr,
1117 				 unsigned int len)
1118 {
1119 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1120 	return !((unsigned long)addr & alignment) && !(len & alignment);
1121 }
1122 
1123 /* assumes size > 256 */
1124 static inline unsigned int blksize_bits(unsigned int size)
1125 {
1126 	unsigned int bits = 8;
1127 	do {
1128 		bits++;
1129 		size >>= 1;
1130 	} while (size > 256);
1131 	return bits;
1132 }
1133 
1134 static inline unsigned int block_size(struct block_device *bdev)
1135 {
1136 	return bdev->bd_block_size;
1137 }
1138 
1139 typedef struct {struct page *v;} Sector;
1140 
1141 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1142 
1143 static inline void put_dev_sector(Sector p)
1144 {
1145 	page_cache_release(p.v);
1146 }
1147 
1148 struct work_struct;
1149 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1150 
1151 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1152 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1153 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1154 	MODULE_ALIAS("block-major-" __stringify(major) "-*")
1155 
1156 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1157 
1158 #define INTEGRITY_FLAG_READ	2	/* verify data integrity on read */
1159 #define INTEGRITY_FLAG_WRITE	4	/* generate data integrity on write */
1160 
1161 struct blk_integrity_exchg {
1162 	void			*prot_buf;
1163 	void			*data_buf;
1164 	sector_t		sector;
1165 	unsigned int		data_size;
1166 	unsigned short		sector_size;
1167 	const char		*disk_name;
1168 };
1169 
1170 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1171 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1172 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1173 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1174 
1175 struct blk_integrity {
1176 	integrity_gen_fn	*generate_fn;
1177 	integrity_vrfy_fn	*verify_fn;
1178 	integrity_set_tag_fn	*set_tag_fn;
1179 	integrity_get_tag_fn	*get_tag_fn;
1180 
1181 	unsigned short		flags;
1182 	unsigned short		tuple_size;
1183 	unsigned short		sector_size;
1184 	unsigned short		tag_size;
1185 
1186 	const char		*name;
1187 
1188 	struct kobject		kobj;
1189 };
1190 
1191 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1192 extern void blk_integrity_unregister(struct gendisk *);
1193 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1194 extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
1195 extern int blk_rq_count_integrity_sg(struct request *);
1196 
1197 static inline
1198 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1199 {
1200 	return bdev->bd_disk->integrity;
1201 }
1202 
1203 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1204 {
1205 	return disk->integrity;
1206 }
1207 
1208 static inline int blk_integrity_rq(struct request *rq)
1209 {
1210 	if (rq->bio == NULL)
1211 		return 0;
1212 
1213 	return bio_integrity(rq->bio);
1214 }
1215 
1216 #else /* CONFIG_BLK_DEV_INTEGRITY */
1217 
1218 #define blk_integrity_rq(rq)			(0)
1219 #define blk_rq_count_integrity_sg(a)		(0)
1220 #define blk_rq_map_integrity_sg(a, b)		(0)
1221 #define bdev_get_integrity(a)			(0)
1222 #define blk_get_integrity(a)			(0)
1223 #define blk_integrity_compare(a, b)		(0)
1224 #define blk_integrity_register(a, b)		(0)
1225 #define blk_integrity_unregister(a)		do { } while (0);
1226 
1227 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1228 
1229 struct block_device_operations {
1230 	int (*open) (struct block_device *, fmode_t);
1231 	int (*release) (struct gendisk *, fmode_t);
1232 	int (*locked_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1233 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1234 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1235 	int (*direct_access) (struct block_device *, sector_t,
1236 						void **, unsigned long *);
1237 	int (*media_changed) (struct gendisk *);
1238 	unsigned long long (*set_capacity) (struct gendisk *,
1239 						unsigned long long);
1240 	int (*revalidate_disk) (struct gendisk *);
1241 	int (*getgeo)(struct block_device *, struct hd_geometry *);
1242 	struct module *owner;
1243 };
1244 
1245 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1246 				 unsigned long);
1247 #else /* CONFIG_BLOCK */
1248 /*
1249  * stubs for when the block layer is configured out
1250  */
1251 #define buffer_heads_over_limit 0
1252 
1253 static inline long nr_blockdev_pages(void)
1254 {
1255 	return 0;
1256 }
1257 
1258 #endif /* CONFIG_BLOCK */
1259 
1260 #endif
1261