xref: /openbmc/linux/include/linux/bio.h (revision 6c870213d6f3a25981c10728f46294a3bed1703f)
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 #include <linux/bug.h>
27 
28 #ifdef CONFIG_BLOCK
29 
30 #include <asm/io.h>
31 
32 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
33 #include <linux/blk_types.h>
34 
35 #define BIO_DEBUG
36 
37 #ifdef BIO_DEBUG
38 #define BIO_BUG_ON	BUG_ON
39 #else
40 #define BIO_BUG_ON
41 #endif
42 
43 #define BIO_MAX_PAGES		256
44 #define BIO_MAX_SIZE		(BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
45 #define BIO_MAX_SECTORS		(BIO_MAX_SIZE >> 9)
46 
47 /*
48  * upper 16 bits of bi_rw define the io priority of this bio
49  */
50 #define BIO_PRIO_SHIFT	(8 * sizeof(unsigned long) - IOPRIO_BITS)
51 #define bio_prio(bio)	((bio)->bi_rw >> BIO_PRIO_SHIFT)
52 #define bio_prio_valid(bio)	ioprio_valid(bio_prio(bio))
53 
54 #define bio_set_prio(bio, prio)		do {			\
55 	WARN_ON(prio >= (1 << IOPRIO_BITS));			\
56 	(bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);		\
57 	(bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);	\
58 } while (0)
59 
60 /*
61  * various member access, note that bio_data should of course not be used
62  * on highmem page vectors
63  */
64 #define __bvec_iter_bvec(bvec, iter)	(&(bvec)[(iter).bi_idx])
65 
66 #define bvec_iter_page(bvec, iter)				\
67 	(__bvec_iter_bvec((bvec), (iter))->bv_page)
68 
69 #define bvec_iter_len(bvec, iter)				\
70 	min((iter).bi_size,					\
71 	    __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
72 
73 #define bvec_iter_offset(bvec, iter)				\
74 	(__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
75 
76 #define bvec_iter_bvec(bvec, iter)				\
77 ((struct bio_vec) {						\
78 	.bv_page	= bvec_iter_page((bvec), (iter)),	\
79 	.bv_len		= bvec_iter_len((bvec), (iter)),	\
80 	.bv_offset	= bvec_iter_offset((bvec), (iter)),	\
81 })
82 
83 #define bio_iter_iovec(bio, iter)				\
84 	bvec_iter_bvec((bio)->bi_io_vec, (iter))
85 
86 #define bio_iter_page(bio, iter)				\
87 	bvec_iter_page((bio)->bi_io_vec, (iter))
88 #define bio_iter_len(bio, iter)					\
89 	bvec_iter_len((bio)->bi_io_vec, (iter))
90 #define bio_iter_offset(bio, iter)				\
91 	bvec_iter_offset((bio)->bi_io_vec, (iter))
92 
93 #define bio_page(bio)		bio_iter_page((bio), (bio)->bi_iter)
94 #define bio_offset(bio)		bio_iter_offset((bio), (bio)->bi_iter)
95 #define bio_iovec(bio)		bio_iter_iovec((bio), (bio)->bi_iter)
96 
97 #define bio_multiple_segments(bio)				\
98 	((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
99 #define bio_sectors(bio)	((bio)->bi_iter.bi_size >> 9)
100 #define bio_end_sector(bio)	((bio)->bi_iter.bi_sector + bio_sectors((bio)))
101 
102 /*
103  * Check whether this bio carries any data or not. A NULL bio is allowed.
104  */
105 static inline bool bio_has_data(struct bio *bio)
106 {
107 	if (bio &&
108 	    bio->bi_iter.bi_size &&
109 	    !(bio->bi_rw & REQ_DISCARD))
110 		return true;
111 
112 	return false;
113 }
114 
115 static inline bool bio_is_rw(struct bio *bio)
116 {
117 	if (!bio_has_data(bio))
118 		return false;
119 
120 	if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
121 		return false;
122 
123 	return true;
124 }
125 
126 static inline bool bio_mergeable(struct bio *bio)
127 {
128 	if (bio->bi_rw & REQ_NOMERGE_FLAGS)
129 		return false;
130 
131 	return true;
132 }
133 
134 static inline unsigned int bio_cur_bytes(struct bio *bio)
135 {
136 	if (bio_has_data(bio))
137 		return bio_iovec(bio).bv_len;
138 	else /* dataless requests such as discard */
139 		return bio->bi_iter.bi_size;
140 }
141 
142 static inline void *bio_data(struct bio *bio)
143 {
144 	if (bio_has_data(bio))
145 		return page_address(bio_page(bio)) + bio_offset(bio);
146 
147 	return NULL;
148 }
149 
150 /*
151  * will die
152  */
153 #define bio_to_phys(bio)	(page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
154 #define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
155 
156 /*
157  * queues that have highmem support enabled may still need to revert to
158  * PIO transfers occasionally and thus map high pages temporarily. For
159  * permanent PIO fall back, user is probably better off disabling highmem
160  * I/O completely on that queue (see ide-dma for example)
161  */
162 #define __bio_kmap_atomic(bio, iter)				\
163 	(kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +	\
164 		bio_iter_iovec((bio), (iter)).bv_offset)
165 
166 #define __bio_kunmap_atomic(addr)	kunmap_atomic(addr)
167 
168 /*
169  * merge helpers etc
170  */
171 
172 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
173 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
174 	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
175 
176 /*
177  * allow arch override, for eg virtualized architectures (put in asm/io.h)
178  */
179 #ifndef BIOVEC_PHYS_MERGEABLE
180 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
181 	__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
182 #endif
183 
184 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
185 	(((addr1) | (mask)) == (((addr2) - 1) | (mask)))
186 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
187 	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
188 
189 #define bio_io_error(bio) bio_endio((bio), -EIO)
190 
191 /*
192  * drivers should _never_ use the all version - the bio may have been split
193  * before it got to the driver and the driver won't own all of it
194  */
195 #define bio_for_each_segment_all(bvl, bio, i)				\
196 	for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
197 
198 static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
199 				     unsigned bytes)
200 {
201 	WARN_ONCE(bytes > iter->bi_size,
202 		  "Attempted to advance past end of bvec iter\n");
203 
204 	while (bytes) {
205 		unsigned len = min(bytes, bvec_iter_len(bv, *iter));
206 
207 		bytes -= len;
208 		iter->bi_size -= len;
209 		iter->bi_bvec_done += len;
210 
211 		if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
212 			iter->bi_bvec_done = 0;
213 			iter->bi_idx++;
214 		}
215 	}
216 }
217 
218 #define for_each_bvec(bvl, bio_vec, iter, start)			\
219 	for (iter = (start);						\
220 	     (iter).bi_size &&						\
221 		((bvl = bvec_iter_bvec((bio_vec), (iter))), 1);	\
222 	     bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
223 
224 
225 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
226 				    unsigned bytes)
227 {
228 	iter->bi_sector += bytes >> 9;
229 
230 	if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
231 		iter->bi_size -= bytes;
232 	else
233 		bvec_iter_advance(bio->bi_io_vec, iter, bytes);
234 }
235 
236 #define __bio_for_each_segment(bvl, bio, iter, start)			\
237 	for (iter = (start);						\
238 	     (iter).bi_size &&						\
239 		((bvl = bio_iter_iovec((bio), (iter))), 1);		\
240 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
241 
242 #define bio_for_each_segment(bvl, bio, iter)				\
243 	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
244 
245 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
246 
247 static inline unsigned bio_segments(struct bio *bio)
248 {
249 	unsigned segs = 0;
250 	struct bio_vec bv;
251 	struct bvec_iter iter;
252 
253 	/*
254 	 * We special case discard/write same, because they interpret bi_size
255 	 * differently:
256 	 */
257 
258 	if (bio->bi_rw & REQ_DISCARD)
259 		return 1;
260 
261 	if (bio->bi_rw & REQ_WRITE_SAME)
262 		return 1;
263 
264 	bio_for_each_segment(bv, bio, iter)
265 		segs++;
266 
267 	return segs;
268 }
269 
270 /*
271  * get a reference to a bio, so it won't disappear. the intended use is
272  * something like:
273  *
274  * bio_get(bio);
275  * submit_bio(rw, bio);
276  * if (bio->bi_flags ...)
277  *	do_something
278  * bio_put(bio);
279  *
280  * without the bio_get(), it could potentially complete I/O before submit_bio
281  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
282  * runs
283  */
284 #define bio_get(bio)	atomic_inc(&(bio)->bi_cnt)
285 
286 #if defined(CONFIG_BLK_DEV_INTEGRITY)
287 /*
288  * bio integrity payload
289  */
290 struct bio_integrity_payload {
291 	struct bio		*bip_bio;	/* parent bio */
292 
293 	struct bvec_iter	bip_iter;
294 
295 	/* kill - should just use bip_vec */
296 	void			*bip_buf;	/* generated integrity data */
297 
298 	bio_end_io_t		*bip_end_io;	/* saved I/O completion fn */
299 
300 	unsigned short		bip_slab;	/* slab the bip came from */
301 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
302 	unsigned		bip_owns_buf:1;	/* should free bip_buf */
303 
304 	struct work_struct	bip_work;	/* I/O completion */
305 
306 	struct bio_vec		*bip_vec;
307 	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
308 };
309 #endif /* CONFIG_BLK_DEV_INTEGRITY */
310 
311 extern void bio_trim(struct bio *bio, int offset, int size);
312 extern struct bio *bio_split(struct bio *bio, int sectors,
313 			     gfp_t gfp, struct bio_set *bs);
314 
315 /**
316  * bio_next_split - get next @sectors from a bio, splitting if necessary
317  * @bio:	bio to split
318  * @sectors:	number of sectors to split from the front of @bio
319  * @gfp:	gfp mask
320  * @bs:		bio set to allocate from
321  *
322  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
323  * than @sectors, returns the original bio unchanged.
324  */
325 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
326 					 gfp_t gfp, struct bio_set *bs)
327 {
328 	if (sectors >= bio_sectors(bio))
329 		return bio;
330 
331 	return bio_split(bio, sectors, gfp, bs);
332 }
333 
334 extern struct bio_set *bioset_create(unsigned int, unsigned int);
335 extern void bioset_free(struct bio_set *);
336 extern mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries);
337 
338 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
339 extern void bio_put(struct bio *);
340 
341 extern void __bio_clone_fast(struct bio *, struct bio *);
342 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
343 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
344 
345 extern struct bio_set *fs_bio_set;
346 unsigned int bio_integrity_tag_size(struct bio *bio);
347 
348 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
349 {
350 	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
351 }
352 
353 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
354 {
355 	return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
356 }
357 
358 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
359 {
360 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
361 }
362 
363 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
364 {
365 	return bio_clone_bioset(bio, gfp_mask, NULL);
366 
367 }
368 
369 extern void bio_endio(struct bio *, int);
370 extern void bio_endio_nodec(struct bio *, int);
371 struct request_queue;
372 extern int bio_phys_segments(struct request_queue *, struct bio *);
373 
374 extern int submit_bio_wait(int rw, struct bio *bio);
375 extern void bio_advance(struct bio *, unsigned);
376 
377 extern void bio_init(struct bio *);
378 extern void bio_reset(struct bio *);
379 void bio_chain(struct bio *, struct bio *);
380 
381 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
382 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
383 			   unsigned int, unsigned int);
384 extern int bio_get_nr_vecs(struct block_device *);
385 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
386 				unsigned long, unsigned int, int, gfp_t);
387 struct sg_iovec;
388 struct rq_map_data;
389 extern struct bio *bio_map_user_iov(struct request_queue *,
390 				    struct block_device *,
391 				    const struct sg_iovec *, int, int, gfp_t);
392 extern void bio_unmap_user(struct bio *);
393 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
394 				gfp_t);
395 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
396 				 gfp_t, int);
397 extern void bio_set_pages_dirty(struct bio *bio);
398 extern void bio_check_pages_dirty(struct bio *bio);
399 
400 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
401 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
402 #endif
403 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
404 extern void bio_flush_dcache_pages(struct bio *bi);
405 #else
406 static inline void bio_flush_dcache_pages(struct bio *bi)
407 {
408 }
409 #endif
410 
411 extern void bio_copy_data(struct bio *dst, struct bio *src);
412 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
413 
414 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
415 				 unsigned long, unsigned int, int, gfp_t);
416 extern struct bio *bio_copy_user_iov(struct request_queue *,
417 				     struct rq_map_data *,
418 				     const struct sg_iovec *,
419 				     int, int, gfp_t);
420 extern int bio_uncopy_user(struct bio *);
421 void zero_fill_bio(struct bio *bio);
422 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
423 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
424 extern unsigned int bvec_nr_vecs(unsigned short idx);
425 
426 #ifdef CONFIG_BLK_CGROUP
427 int bio_associate_current(struct bio *bio);
428 void bio_disassociate_task(struct bio *bio);
429 #else	/* CONFIG_BLK_CGROUP */
430 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
431 static inline void bio_disassociate_task(struct bio *bio) { }
432 #endif	/* CONFIG_BLK_CGROUP */
433 
434 #ifdef CONFIG_HIGHMEM
435 /*
436  * remember never ever reenable interrupts between a bvec_kmap_irq and
437  * bvec_kunmap_irq!
438  */
439 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
440 {
441 	unsigned long addr;
442 
443 	/*
444 	 * might not be a highmem page, but the preempt/irq count
445 	 * balancing is a lot nicer this way
446 	 */
447 	local_irq_save(*flags);
448 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
449 
450 	BUG_ON(addr & ~PAGE_MASK);
451 
452 	return (char *) addr + bvec->bv_offset;
453 }
454 
455 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
456 {
457 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
458 
459 	kunmap_atomic((void *) ptr);
460 	local_irq_restore(*flags);
461 }
462 
463 #else
464 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
465 {
466 	return page_address(bvec->bv_page) + bvec->bv_offset;
467 }
468 
469 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
470 {
471 	*flags = 0;
472 }
473 #endif
474 
475 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
476 				   unsigned long *flags)
477 {
478 	return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
479 }
480 #define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)
481 
482 #define bio_kmap_irq(bio, flags) \
483 	__bio_kmap_irq((bio), (bio)->bi_iter, (flags))
484 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
485 
486 /*
487  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
488  *
489  * A bio_list anchors a singly-linked list of bios chained through the bi_next
490  * member of the bio.  The bio_list also caches the last list member to allow
491  * fast access to the tail.
492  */
493 struct bio_list {
494 	struct bio *head;
495 	struct bio *tail;
496 };
497 
498 static inline int bio_list_empty(const struct bio_list *bl)
499 {
500 	return bl->head == NULL;
501 }
502 
503 static inline void bio_list_init(struct bio_list *bl)
504 {
505 	bl->head = bl->tail = NULL;
506 }
507 
508 #define BIO_EMPTY_LIST	{ NULL, NULL }
509 
510 #define bio_list_for_each(bio, bl) \
511 	for (bio = (bl)->head; bio; bio = bio->bi_next)
512 
513 static inline unsigned bio_list_size(const struct bio_list *bl)
514 {
515 	unsigned sz = 0;
516 	struct bio *bio;
517 
518 	bio_list_for_each(bio, bl)
519 		sz++;
520 
521 	return sz;
522 }
523 
524 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
525 {
526 	bio->bi_next = NULL;
527 
528 	if (bl->tail)
529 		bl->tail->bi_next = bio;
530 	else
531 		bl->head = bio;
532 
533 	bl->tail = bio;
534 }
535 
536 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
537 {
538 	bio->bi_next = bl->head;
539 
540 	bl->head = bio;
541 
542 	if (!bl->tail)
543 		bl->tail = bio;
544 }
545 
546 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
547 {
548 	if (!bl2->head)
549 		return;
550 
551 	if (bl->tail)
552 		bl->tail->bi_next = bl2->head;
553 	else
554 		bl->head = bl2->head;
555 
556 	bl->tail = bl2->tail;
557 }
558 
559 static inline void bio_list_merge_head(struct bio_list *bl,
560 				       struct bio_list *bl2)
561 {
562 	if (!bl2->head)
563 		return;
564 
565 	if (bl->head)
566 		bl2->tail->bi_next = bl->head;
567 	else
568 		bl->tail = bl2->tail;
569 
570 	bl->head = bl2->head;
571 }
572 
573 static inline struct bio *bio_list_peek(struct bio_list *bl)
574 {
575 	return bl->head;
576 }
577 
578 static inline struct bio *bio_list_pop(struct bio_list *bl)
579 {
580 	struct bio *bio = bl->head;
581 
582 	if (bio) {
583 		bl->head = bl->head->bi_next;
584 		if (!bl->head)
585 			bl->tail = NULL;
586 
587 		bio->bi_next = NULL;
588 	}
589 
590 	return bio;
591 }
592 
593 static inline struct bio *bio_list_get(struct bio_list *bl)
594 {
595 	struct bio *bio = bl->head;
596 
597 	bl->head = bl->tail = NULL;
598 
599 	return bio;
600 }
601 
602 /*
603  * bio_set is used to allow other portions of the IO system to
604  * allocate their own private memory pools for bio and iovec structures.
605  * These memory pools in turn all allocate from the bio_slab
606  * and the bvec_slabs[].
607  */
608 #define BIO_POOL_SIZE 2
609 #define BIOVEC_NR_POOLS 6
610 #define BIOVEC_MAX_IDX	(BIOVEC_NR_POOLS - 1)
611 
612 struct bio_set {
613 	struct kmem_cache *bio_slab;
614 	unsigned int front_pad;
615 
616 	mempool_t *bio_pool;
617 	mempool_t *bvec_pool;
618 #if defined(CONFIG_BLK_DEV_INTEGRITY)
619 	mempool_t *bio_integrity_pool;
620 	mempool_t *bvec_integrity_pool;
621 #endif
622 
623 	/*
624 	 * Deadlock avoidance for stacking block drivers: see comments in
625 	 * bio_alloc_bioset() for details
626 	 */
627 	spinlock_t		rescue_lock;
628 	struct bio_list		rescue_list;
629 	struct work_struct	rescue_work;
630 	struct workqueue_struct	*rescue_workqueue;
631 };
632 
633 struct biovec_slab {
634 	int nr_vecs;
635 	char *name;
636 	struct kmem_cache *slab;
637 };
638 
639 /*
640  * a small number of entries is fine, not going to be performance critical.
641  * basically we just need to survive
642  */
643 #define BIO_SPLIT_ENTRIES 2
644 
645 #if defined(CONFIG_BLK_DEV_INTEGRITY)
646 
647 
648 
649 #define bip_vec_idx(bip, idx)	(&(bip->bip_vec[(idx)]))
650 
651 #define bip_for_each_vec(bvl, bip, iter)				\
652 	for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
653 
654 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
655 	for_each_bio(_bio)						\
656 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
657 
658 #define bio_integrity(bio) (bio->bi_integrity != NULL)
659 
660 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
661 extern void bio_integrity_free(struct bio *);
662 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
663 extern int bio_integrity_enabled(struct bio *bio);
664 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
665 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
666 extern int bio_integrity_prep(struct bio *);
667 extern void bio_integrity_endio(struct bio *, int);
668 extern void bio_integrity_advance(struct bio *, unsigned int);
669 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
670 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
671 extern int bioset_integrity_create(struct bio_set *, int);
672 extern void bioset_integrity_free(struct bio_set *);
673 extern void bio_integrity_init(void);
674 
675 #else /* CONFIG_BLK_DEV_INTEGRITY */
676 
677 static inline int bio_integrity(struct bio *bio)
678 {
679 	return 0;
680 }
681 
682 static inline int bio_integrity_enabled(struct bio *bio)
683 {
684 	return 0;
685 }
686 
687 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
688 {
689 	return 0;
690 }
691 
692 static inline void bioset_integrity_free (struct bio_set *bs)
693 {
694 	return;
695 }
696 
697 static inline int bio_integrity_prep(struct bio *bio)
698 {
699 	return 0;
700 }
701 
702 static inline void bio_integrity_free(struct bio *bio)
703 {
704 	return;
705 }
706 
707 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
708 				      gfp_t gfp_mask)
709 {
710 	return 0;
711 }
712 
713 static inline void bio_integrity_advance(struct bio *bio,
714 					 unsigned int bytes_done)
715 {
716 	return;
717 }
718 
719 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
720 				      unsigned int sectors)
721 {
722 	return;
723 }
724 
725 static inline void bio_integrity_init(void)
726 {
727 	return;
728 }
729 
730 #endif /* CONFIG_BLK_DEV_INTEGRITY */
731 
732 #endif /* CONFIG_BLOCK */
733 #endif /* __LINUX_BIO_H */
734