xref: /openbmc/linux/include/linux/bio.h (revision a09d2831)
1 /*
2  * 2.5 block I/O model
3  *
4  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public Licens
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
19  */
20 #ifndef __LINUX_BIO_H
21 #define __LINUX_BIO_H
22 
23 #include <linux/highmem.h>
24 #include <linux/mempool.h>
25 #include <linux/ioprio.h>
26 
27 #ifdef CONFIG_BLOCK
28 
29 #include <asm/io.h>
30 
31 #define BIO_DEBUG
32 
33 #ifdef BIO_DEBUG
34 #define BIO_BUG_ON	BUG_ON
35 #else
36 #define BIO_BUG_ON
37 #endif
38 
39 #define BIO_MAX_PAGES		256
40 #define BIO_MAX_SIZE		(BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
41 #define BIO_MAX_SECTORS		(BIO_MAX_SIZE >> 9)
42 
43 /*
44  * was unsigned short, but we might as well be ready for > 64kB I/O pages
45  */
46 struct bio_vec {
47 	struct page	*bv_page;
48 	unsigned int	bv_len;
49 	unsigned int	bv_offset;
50 };
51 
52 struct bio_set;
53 struct bio;
54 struct bio_integrity_payload;
55 typedef void (bio_end_io_t) (struct bio *, int);
56 typedef void (bio_destructor_t) (struct bio *);
57 
58 /*
59  * main unit of I/O for the block layer and lower layers (ie drivers and
60  * stacking drivers)
61  */
62 struct bio {
63 	sector_t		bi_sector;	/* device address in 512 byte
64 						   sectors */
65 	struct bio		*bi_next;	/* request queue link */
66 	struct block_device	*bi_bdev;
67 	unsigned long		bi_flags;	/* status, command, etc */
68 	unsigned long		bi_rw;		/* bottom bits READ/WRITE,
69 						 * top bits priority
70 						 */
71 
72 	unsigned short		bi_vcnt;	/* how many bio_vec's */
73 	unsigned short		bi_idx;		/* current index into bvl_vec */
74 
75 	/* Number of segments in this BIO after
76 	 * physical address coalescing is performed.
77 	 */
78 	unsigned int		bi_phys_segments;
79 
80 	unsigned int		bi_size;	/* residual I/O count */
81 
82 	/*
83 	 * To keep track of the max segment size, we account for the
84 	 * sizes of the first and last mergeable segments in this bio.
85 	 */
86 	unsigned int		bi_seg_front_size;
87 	unsigned int		bi_seg_back_size;
88 
89 	unsigned int		bi_max_vecs;	/* max bvl_vecs we can hold */
90 
91 	unsigned int		bi_comp_cpu;	/* completion CPU */
92 
93 	atomic_t		bi_cnt;		/* pin count */
94 
95 	struct bio_vec		*bi_io_vec;	/* the actual vec list */
96 
97 	bio_end_io_t		*bi_end_io;
98 
99 	void			*bi_private;
100 #if defined(CONFIG_BLK_DEV_INTEGRITY)
101 	struct bio_integrity_payload *bi_integrity;  /* data integrity */
102 #endif
103 
104 	bio_destructor_t	*bi_destructor;	/* destructor */
105 
106 	/*
107 	 * We can inline a number of vecs at the end of the bio, to avoid
108 	 * double allocations for a small number of bio_vecs. This member
109 	 * MUST obviously be kept at the very end of the bio.
110 	 */
111 	struct bio_vec		bi_inline_vecs[0];
112 };
113 
114 /*
115  * bio flags
116  */
117 #define BIO_UPTODATE	0	/* ok after I/O completion */
118 #define BIO_RW_BLOCK	1	/* RW_AHEAD set, and read/write would block */
119 #define BIO_EOF		2	/* out-out-bounds error */
120 #define BIO_SEG_VALID	3	/* bi_phys_segments valid */
121 #define BIO_CLONED	4	/* doesn't own data */
122 #define BIO_BOUNCED	5	/* bio is a bounce bio */
123 #define BIO_USER_MAPPED 6	/* contains user pages */
124 #define BIO_EOPNOTSUPP	7	/* not supported */
125 #define BIO_CPU_AFFINE	8	/* complete bio on same CPU as submitted */
126 #define BIO_NULL_MAPPED 9	/* contains invalid user pages */
127 #define BIO_FS_INTEGRITY 10	/* fs owns integrity data, not block layer */
128 #define BIO_QUIET	11	/* Make BIO Quiet */
129 #define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))
130 
131 /*
132  * top 4 bits of bio flags indicate the pool this bio came from
133  */
134 #define BIO_POOL_BITS		(4)
135 #define BIO_POOL_NONE		((1UL << BIO_POOL_BITS) - 1)
136 #define BIO_POOL_OFFSET		(BITS_PER_LONG - BIO_POOL_BITS)
137 #define BIO_POOL_MASK		(1UL << BIO_POOL_OFFSET)
138 #define BIO_POOL_IDX(bio)	((bio)->bi_flags >> BIO_POOL_OFFSET)
139 
140 /*
141  * bio bi_rw flags
142  *
143  * bit 0 -- data direction
144  *	If not set, bio is a read from device. If set, it's a write to device.
145  * bit 1 -- fail fast device errors
146  * bit 2 -- fail fast transport errors
147  * bit 3 -- fail fast driver errors
148  * bit 4 -- rw-ahead when set
149  * bit 5 -- barrier
150  *	Insert a serialization point in the IO queue, forcing previously
151  *	submitted IO to be completed before this one is issued.
152  * bit 6 -- synchronous I/O hint.
153  * bit 7 -- Unplug the device immediately after submitting this bio.
154  * bit 8 -- metadata request
155  *	Used for tracing to differentiate metadata and data IO. May also
156  *	get some preferential treatment in the IO scheduler
157  * bit 9 -- discard sectors
158  *	Informs the lower level device that this range of sectors is no longer
159  *	used by the file system and may thus be freed by the device. Used
160  *	for flash based storage.
161  *	Don't want driver retries for any fast fail whatever the reason.
162  * bit 10 -- Tell the IO scheduler not to wait for more requests after this
163 	one has been submitted, even if it is a SYNC request.
164  */
165 enum bio_rw_flags {
166 	BIO_RW,
167 	BIO_RW_FAILFAST_DEV,
168 	BIO_RW_FAILFAST_TRANSPORT,
169 	BIO_RW_FAILFAST_DRIVER,
170 	/* above flags must match REQ_* */
171 	BIO_RW_AHEAD,
172 	BIO_RW_BARRIER,
173 	BIO_RW_SYNCIO,
174 	BIO_RW_UNPLUG,
175 	BIO_RW_META,
176 	BIO_RW_DISCARD,
177 	BIO_RW_NOIDLE,
178 };
179 
180 /*
181  * First four bits must match between bio->bi_rw and rq->cmd_flags, make
182  * that explicit here.
183  */
184 #define BIO_RW_RQ_MASK		0xf
185 
186 static inline bool bio_rw_flagged(struct bio *bio, enum bio_rw_flags flag)
187 {
188 	return (bio->bi_rw & (1 << flag)) != 0;
189 }
190 
191 /*
192  * upper 16 bits of bi_rw define the io priority of this bio
193  */
194 #define BIO_PRIO_SHIFT	(8 * sizeof(unsigned long) - IOPRIO_BITS)
195 #define bio_prio(bio)	((bio)->bi_rw >> BIO_PRIO_SHIFT)
196 #define bio_prio_valid(bio)	ioprio_valid(bio_prio(bio))
197 
198 #define bio_set_prio(bio, prio)		do {			\
199 	WARN_ON(prio >= (1 << IOPRIO_BITS));			\
200 	(bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);		\
201 	(bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);	\
202 } while (0)
203 
204 /*
205  * various member access, note that bio_data should of course not be used
206  * on highmem page vectors
207  */
208 #define bio_iovec_idx(bio, idx)	(&((bio)->bi_io_vec[(idx)]))
209 #define bio_iovec(bio)		bio_iovec_idx((bio), (bio)->bi_idx)
210 #define bio_page(bio)		bio_iovec((bio))->bv_page
211 #define bio_offset(bio)		bio_iovec((bio))->bv_offset
212 #define bio_segments(bio)	((bio)->bi_vcnt - (bio)->bi_idx)
213 #define bio_sectors(bio)	((bio)->bi_size >> 9)
214 #define bio_empty_barrier(bio)	(bio_rw_flagged(bio, BIO_RW_BARRIER) && !bio_has_data(bio) && !bio_rw_flagged(bio, BIO_RW_DISCARD))
215 
216 static inline unsigned int bio_cur_bytes(struct bio *bio)
217 {
218 	if (bio->bi_vcnt)
219 		return bio_iovec(bio)->bv_len;
220 	else /* dataless requests such as discard */
221 		return bio->bi_size;
222 }
223 
224 static inline void *bio_data(struct bio *bio)
225 {
226 	if (bio->bi_vcnt)
227 		return page_address(bio_page(bio)) + bio_offset(bio);
228 
229 	return NULL;
230 }
231 
232 static inline int bio_has_allocated_vec(struct bio *bio)
233 {
234 	return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
235 }
236 
237 /*
238  * will die
239  */
240 #define bio_to_phys(bio)	(page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
241 #define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
242 
243 /*
244  * queues that have highmem support enabled may still need to revert to
245  * PIO transfers occasionally and thus map high pages temporarily. For
246  * permanent PIO fall back, user is probably better off disabling highmem
247  * I/O completely on that queue (see ide-dma for example)
248  */
249 #define __bio_kmap_atomic(bio, idx, kmtype)				\
250 	(kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) +	\
251 		bio_iovec_idx((bio), (idx))->bv_offset)
252 
253 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
254 
255 /*
256  * merge helpers etc
257  */
258 
259 #define __BVEC_END(bio)		bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
260 #define __BVEC_START(bio)	bio_iovec_idx((bio), (bio)->bi_idx)
261 
262 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
263 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
264 	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
265 
266 /*
267  * allow arch override, for eg virtualized architectures (put in asm/io.h)
268  */
269 #ifndef BIOVEC_PHYS_MERGEABLE
270 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
271 	__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
272 #endif
273 
274 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
275 	(((addr1) | (mask)) == (((addr2) - 1) | (mask)))
276 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
277 	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
278 #define BIO_SEG_BOUNDARY(q, b1, b2) \
279 	BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
280 
281 #define bio_io_error(bio) bio_endio((bio), -EIO)
282 
283 /*
284  * drivers should not use the __ version unless they _really_ want to
285  * run through the entire bio and not just pending pieces
286  */
287 #define __bio_for_each_segment(bvl, bio, i, start_idx)			\
288 	for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);	\
289 	     i < (bio)->bi_vcnt;					\
290 	     bvl++, i++)
291 
292 #define bio_for_each_segment(bvl, bio, i)				\
293 	__bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
294 
295 /*
296  * get a reference to a bio, so it won't disappear. the intended use is
297  * something like:
298  *
299  * bio_get(bio);
300  * submit_bio(rw, bio);
301  * if (bio->bi_flags ...)
302  *	do_something
303  * bio_put(bio);
304  *
305  * without the bio_get(), it could potentially complete I/O before submit_bio
306  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
307  * runs
308  */
309 #define bio_get(bio)	atomic_inc(&(bio)->bi_cnt)
310 
311 #if defined(CONFIG_BLK_DEV_INTEGRITY)
312 /*
313  * bio integrity payload
314  */
315 struct bio_integrity_payload {
316 	struct bio		*bip_bio;	/* parent bio */
317 
318 	sector_t		bip_sector;	/* virtual start sector */
319 
320 	void			*bip_buf;	/* generated integrity data */
321 	bio_end_io_t		*bip_end_io;	/* saved I/O completion fn */
322 
323 	unsigned int		bip_size;
324 
325 	unsigned short		bip_slab;	/* slab the bip came from */
326 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
327 	unsigned short		bip_idx;	/* current bip_vec index */
328 
329 	struct work_struct	bip_work;	/* I/O completion */
330 	struct bio_vec		bip_vec[0];	/* embedded bvec array */
331 };
332 #endif /* CONFIG_BLK_DEV_INTEGRITY */
333 
334 /*
335  * A bio_pair is used when we need to split a bio.
336  * This can only happen for a bio that refers to just one
337  * page of data, and in the unusual situation when the
338  * page crosses a chunk/device boundary
339  *
340  * The address of the master bio is stored in bio1.bi_private
341  * The address of the pool the pair was allocated from is stored
342  *   in bio2.bi_private
343  */
344 struct bio_pair {
345 	struct bio			bio1, bio2;
346 	struct bio_vec			bv1, bv2;
347 #if defined(CONFIG_BLK_DEV_INTEGRITY)
348 	struct bio_integrity_payload	bip1, bip2;
349 	struct bio_vec			iv1, iv2;
350 #endif
351 	atomic_t			cnt;
352 	int				error;
353 };
354 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
355 extern void bio_pair_release(struct bio_pair *dbio);
356 
357 extern struct bio_set *bioset_create(unsigned int, unsigned int);
358 extern void bioset_free(struct bio_set *);
359 
360 extern struct bio *bio_alloc(gfp_t, int);
361 extern struct bio *bio_kmalloc(gfp_t, int);
362 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
363 extern void bio_put(struct bio *);
364 extern void bio_free(struct bio *, struct bio_set *);
365 
366 extern void bio_endio(struct bio *, int);
367 struct request_queue;
368 extern int bio_phys_segments(struct request_queue *, struct bio *);
369 
370 extern void __bio_clone(struct bio *, struct bio *);
371 extern struct bio *bio_clone(struct bio *, gfp_t);
372 
373 extern void bio_init(struct bio *);
374 
375 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
376 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
377 			   unsigned int, unsigned int);
378 extern int bio_get_nr_vecs(struct block_device *);
379 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
380 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
381 				unsigned long, unsigned int, int, gfp_t);
382 struct sg_iovec;
383 struct rq_map_data;
384 extern struct bio *bio_map_user_iov(struct request_queue *,
385 				    struct block_device *,
386 				    struct sg_iovec *, int, int, gfp_t);
387 extern void bio_unmap_user(struct bio *);
388 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
389 				gfp_t);
390 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
391 				 gfp_t, int);
392 extern void bio_set_pages_dirty(struct bio *bio);
393 extern void bio_check_pages_dirty(struct bio *bio);
394 
395 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
396 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
397 #endif
398 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
399 extern void bio_flush_dcache_pages(struct bio *bi);
400 #else
401 static inline void bio_flush_dcache_pages(struct bio *bi)
402 {
403 }
404 #endif
405 
406 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
407 				 unsigned long, unsigned int, int, gfp_t);
408 extern struct bio *bio_copy_user_iov(struct request_queue *,
409 				     struct rq_map_data *, struct sg_iovec *,
410 				     int, int, gfp_t);
411 extern int bio_uncopy_user(struct bio *);
412 void zero_fill_bio(struct bio *bio);
413 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
414 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
415 extern unsigned int bvec_nr_vecs(unsigned short idx);
416 
417 /*
418  * Allow queuer to specify a completion CPU for this bio
419  */
420 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
421 {
422 	bio->bi_comp_cpu = cpu;
423 }
424 
425 /*
426  * bio_set is used to allow other portions of the IO system to
427  * allocate their own private memory pools for bio and iovec structures.
428  * These memory pools in turn all allocate from the bio_slab
429  * and the bvec_slabs[].
430  */
431 #define BIO_POOL_SIZE 2
432 #define BIOVEC_NR_POOLS 6
433 #define BIOVEC_MAX_IDX	(BIOVEC_NR_POOLS - 1)
434 
435 struct bio_set {
436 	struct kmem_cache *bio_slab;
437 	unsigned int front_pad;
438 
439 	mempool_t *bio_pool;
440 #if defined(CONFIG_BLK_DEV_INTEGRITY)
441 	mempool_t *bio_integrity_pool;
442 #endif
443 	mempool_t *bvec_pool;
444 };
445 
446 struct biovec_slab {
447 	int nr_vecs;
448 	char *name;
449 	struct kmem_cache *slab;
450 };
451 
452 extern struct bio_set *fs_bio_set;
453 extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly;
454 
455 /*
456  * a small number of entries is fine, not going to be performance critical.
457  * basically we just need to survive
458  */
459 #define BIO_SPLIT_ENTRIES 2
460 
461 #ifdef CONFIG_HIGHMEM
462 /*
463  * remember never ever reenable interrupts between a bvec_kmap_irq and
464  * bvec_kunmap_irq!
465  */
466 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
467 {
468 	unsigned long addr;
469 
470 	/*
471 	 * might not be a highmem page, but the preempt/irq count
472 	 * balancing is a lot nicer this way
473 	 */
474 	local_irq_save(*flags);
475 	addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
476 
477 	BUG_ON(addr & ~PAGE_MASK);
478 
479 	return (char *) addr + bvec->bv_offset;
480 }
481 
482 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
483 {
484 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
485 
486 	kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
487 	local_irq_restore(*flags);
488 }
489 
490 #else
491 #define bvec_kmap_irq(bvec, flags)	(page_address((bvec)->bv_page) + (bvec)->bv_offset)
492 #define bvec_kunmap_irq(buf, flags)	do { *(flags) = 0; } while (0)
493 #endif
494 
495 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
496 				   unsigned long *flags)
497 {
498 	return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
499 }
500 #define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)
501 
502 #define bio_kmap_irq(bio, flags) \
503 	__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
504 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
505 
506 /*
507  * Check whether this bio carries any data or not. A NULL bio is allowed.
508  */
509 static inline int bio_has_data(struct bio *bio)
510 {
511 	return bio && bio->bi_io_vec != NULL;
512 }
513 
514 /*
515  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
516  *
517  * A bio_list anchors a singly-linked list of bios chained through the bi_next
518  * member of the bio.  The bio_list also caches the last list member to allow
519  * fast access to the tail.
520  */
521 struct bio_list {
522 	struct bio *head;
523 	struct bio *tail;
524 };
525 
526 static inline int bio_list_empty(const struct bio_list *bl)
527 {
528 	return bl->head == NULL;
529 }
530 
531 static inline void bio_list_init(struct bio_list *bl)
532 {
533 	bl->head = bl->tail = NULL;
534 }
535 
536 #define bio_list_for_each(bio, bl) \
537 	for (bio = (bl)->head; bio; bio = bio->bi_next)
538 
539 static inline unsigned bio_list_size(const struct bio_list *bl)
540 {
541 	unsigned sz = 0;
542 	struct bio *bio;
543 
544 	bio_list_for_each(bio, bl)
545 		sz++;
546 
547 	return sz;
548 }
549 
550 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
551 {
552 	bio->bi_next = NULL;
553 
554 	if (bl->tail)
555 		bl->tail->bi_next = bio;
556 	else
557 		bl->head = bio;
558 
559 	bl->tail = bio;
560 }
561 
562 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
563 {
564 	bio->bi_next = bl->head;
565 
566 	bl->head = bio;
567 
568 	if (!bl->tail)
569 		bl->tail = bio;
570 }
571 
572 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
573 {
574 	if (!bl2->head)
575 		return;
576 
577 	if (bl->tail)
578 		bl->tail->bi_next = bl2->head;
579 	else
580 		bl->head = bl2->head;
581 
582 	bl->tail = bl2->tail;
583 }
584 
585 static inline void bio_list_merge_head(struct bio_list *bl,
586 				       struct bio_list *bl2)
587 {
588 	if (!bl2->head)
589 		return;
590 
591 	if (bl->head)
592 		bl2->tail->bi_next = bl->head;
593 	else
594 		bl->tail = bl2->tail;
595 
596 	bl->head = bl2->head;
597 }
598 
599 static inline struct bio *bio_list_peek(struct bio_list *bl)
600 {
601 	return bl->head;
602 }
603 
604 static inline struct bio *bio_list_pop(struct bio_list *bl)
605 {
606 	struct bio *bio = bl->head;
607 
608 	if (bio) {
609 		bl->head = bl->head->bi_next;
610 		if (!bl->head)
611 			bl->tail = NULL;
612 
613 		bio->bi_next = NULL;
614 	}
615 
616 	return bio;
617 }
618 
619 static inline struct bio *bio_list_get(struct bio_list *bl)
620 {
621 	struct bio *bio = bl->head;
622 
623 	bl->head = bl->tail = NULL;
624 
625 	return bio;
626 }
627 
628 #if defined(CONFIG_BLK_DEV_INTEGRITY)
629 
630 #define bip_vec_idx(bip, idx)	(&(bip->bip_vec[(idx)]))
631 #define bip_vec(bip)		bip_vec_idx(bip, 0)
632 
633 #define __bip_for_each_vec(bvl, bip, i, start_idx)			\
634 	for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);	\
635 	     i < (bip)->bip_vcnt;					\
636 	     bvl++, i++)
637 
638 #define bip_for_each_vec(bvl, bip, i)					\
639 	__bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
640 
641 #define bio_integrity(bio) (bio->bi_integrity != NULL)
642 
643 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
644 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
645 extern void bio_integrity_free(struct bio *, struct bio_set *);
646 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
647 extern int bio_integrity_enabled(struct bio *bio);
648 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
649 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
650 extern int bio_integrity_prep(struct bio *);
651 extern void bio_integrity_endio(struct bio *, int);
652 extern void bio_integrity_advance(struct bio *, unsigned int);
653 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
654 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
655 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
656 extern int bioset_integrity_create(struct bio_set *, int);
657 extern void bioset_integrity_free(struct bio_set *);
658 extern void bio_integrity_init(void);
659 
660 #else /* CONFIG_BLK_DEV_INTEGRITY */
661 
662 #define bio_integrity(a)		(0)
663 #define bioset_integrity_create(a, b)	(0)
664 #define bio_integrity_prep(a)		(0)
665 #define bio_integrity_enabled(a)	(0)
666 #define bio_integrity_clone(a, b, c, d)	(0)
667 #define bioset_integrity_free(a)	do { } while (0)
668 #define bio_integrity_free(a, b)	do { } while (0)
669 #define bio_integrity_endio(a, b)	do { } while (0)
670 #define bio_integrity_advance(a, b)	do { } while (0)
671 #define bio_integrity_trim(a, b, c)	do { } while (0)
672 #define bio_integrity_split(a, b, c)	do { } while (0)
673 #define bio_integrity_set_tag(a, b, c)	do { } while (0)
674 #define bio_integrity_get_tag(a, b, c)	do { } while (0)
675 #define bio_integrity_init(a)		do { } while (0)
676 
677 #endif /* CONFIG_BLK_DEV_INTEGRITY */
678 
679 #endif /* CONFIG_BLOCK */
680 #endif /* __LINUX_BIO_H */
681