xref: /openbmc/linux/include/linux/bio.h (revision 0bea2a65)
1 /*
2  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  *
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public Licens
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
17  */
18 #ifndef __LINUX_BIO_H
19 #define __LINUX_BIO_H
20 
21 #include <linux/highmem.h>
22 #include <linux/mempool.h>
23 #include <linux/ioprio.h>
24 #include <linux/bug.h>
25 
26 #ifdef CONFIG_BLOCK
27 
28 #include <asm/io.h>
29 
30 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
31 #include <linux/blk_types.h>
32 
33 #define BIO_DEBUG
34 
35 #ifdef BIO_DEBUG
36 #define BIO_BUG_ON	BUG_ON
37 #else
38 #define BIO_BUG_ON
39 #endif
40 
41 #ifdef CONFIG_THP_SWAP
42 #if HPAGE_PMD_NR > 256
43 #define BIO_MAX_PAGES		HPAGE_PMD_NR
44 #else
45 #define BIO_MAX_PAGES		256
46 #endif
47 #else
48 #define BIO_MAX_PAGES		256
49 #endif
50 
51 #define bio_prio(bio)			(bio)->bi_ioprio
52 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
53 
54 #define bio_iter_iovec(bio, iter)				\
55 	bvec_iter_bvec((bio)->bi_io_vec, (iter))
56 
57 #define bio_iter_page(bio, iter)				\
58 	bvec_iter_page((bio)->bi_io_vec, (iter))
59 #define bio_iter_len(bio, iter)					\
60 	bvec_iter_len((bio)->bi_io_vec, (iter))
61 #define bio_iter_offset(bio, iter)				\
62 	bvec_iter_offset((bio)->bi_io_vec, (iter))
63 
64 #define bio_page(bio)		bio_iter_page((bio), (bio)->bi_iter)
65 #define bio_offset(bio)		bio_iter_offset((bio), (bio)->bi_iter)
66 #define bio_iovec(bio)		bio_iter_iovec((bio), (bio)->bi_iter)
67 
68 #define bio_multiple_segments(bio)				\
69 	((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
70 #define bio_sectors(bio)	((bio)->bi_iter.bi_size >> 9)
71 #define bio_end_sector(bio)	((bio)->bi_iter.bi_sector + bio_sectors((bio)))
72 
73 /*
74  * Return the data direction, READ or WRITE.
75  */
76 #define bio_data_dir(bio) \
77 	(op_is_write(bio_op(bio)) ? WRITE : READ)
78 
79 /*
80  * Check whether this bio carries any data or not. A NULL bio is allowed.
81  */
82 static inline bool bio_has_data(struct bio *bio)
83 {
84 	if (bio &&
85 	    bio->bi_iter.bi_size &&
86 	    bio_op(bio) != REQ_OP_DISCARD &&
87 	    bio_op(bio) != REQ_OP_SECURE_ERASE &&
88 	    bio_op(bio) != REQ_OP_WRITE_ZEROES)
89 		return true;
90 
91 	return false;
92 }
93 
94 static inline bool bio_no_advance_iter(struct bio *bio)
95 {
96 	return bio_op(bio) == REQ_OP_DISCARD ||
97 	       bio_op(bio) == REQ_OP_SECURE_ERASE ||
98 	       bio_op(bio) == REQ_OP_WRITE_SAME ||
99 	       bio_op(bio) == REQ_OP_WRITE_ZEROES;
100 }
101 
102 static inline bool bio_mergeable(struct bio *bio)
103 {
104 	if (bio->bi_opf & REQ_NOMERGE_FLAGS)
105 		return false;
106 
107 	return true;
108 }
109 
110 static inline unsigned int bio_cur_bytes(struct bio *bio)
111 {
112 	if (bio_has_data(bio))
113 		return bio_iovec(bio).bv_len;
114 	else /* dataless requests such as discard */
115 		return bio->bi_iter.bi_size;
116 }
117 
118 static inline void *bio_data(struct bio *bio)
119 {
120 	if (bio_has_data(bio))
121 		return page_address(bio_page(bio)) + bio_offset(bio);
122 
123 	return NULL;
124 }
125 
126 /*
127  * will die
128  */
129 #define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
130 
131 /*
132  * merge helpers etc
133  */
134 
135 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
136 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
137 	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
138 
139 /*
140  * allow arch override, for eg virtualized architectures (put in asm/io.h)
141  */
142 #ifndef BIOVEC_PHYS_MERGEABLE
143 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
144 	__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
145 #endif
146 
147 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
148 	(((addr1) | (mask)) == (((addr2) - 1) | (mask)))
149 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
150 	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
151 
152 /*
153  * drivers should _never_ use the all version - the bio may have been split
154  * before it got to the driver and the driver won't own all of it
155  */
156 #define bio_for_each_segment_all(bvl, bio, i)				\
157 	for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
158 
159 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
160 				    unsigned bytes)
161 {
162 	iter->bi_sector += bytes >> 9;
163 
164 	if (bio_no_advance_iter(bio)) {
165 		iter->bi_size -= bytes;
166 		iter->bi_done += bytes;
167 	} else {
168 		bvec_iter_advance(bio->bi_io_vec, iter, bytes);
169 		/* TODO: It is reasonable to complete bio with error here. */
170 	}
171 }
172 
173 static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
174 		unsigned int bytes)
175 {
176 	iter->bi_sector -= bytes >> 9;
177 
178 	if (bio_no_advance_iter(bio)) {
179 		iter->bi_size += bytes;
180 		iter->bi_done -= bytes;
181 		return true;
182 	}
183 
184 	return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
185 }
186 
187 #define __bio_for_each_segment(bvl, bio, iter, start)			\
188 	for (iter = (start);						\
189 	     (iter).bi_size &&						\
190 		((bvl = bio_iter_iovec((bio), (iter))), 1);		\
191 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
192 
193 #define bio_for_each_segment(bvl, bio, iter)				\
194 	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
195 
196 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
197 
198 static inline unsigned bio_segments(struct bio *bio)
199 {
200 	unsigned segs = 0;
201 	struct bio_vec bv;
202 	struct bvec_iter iter;
203 
204 	/*
205 	 * We special case discard/write same/write zeroes, because they
206 	 * interpret bi_size differently:
207 	 */
208 
209 	switch (bio_op(bio)) {
210 	case REQ_OP_DISCARD:
211 	case REQ_OP_SECURE_ERASE:
212 	case REQ_OP_WRITE_ZEROES:
213 		return 0;
214 	case REQ_OP_WRITE_SAME:
215 		return 1;
216 	default:
217 		break;
218 	}
219 
220 	bio_for_each_segment(bv, bio, iter)
221 		segs++;
222 
223 	return segs;
224 }
225 
226 /*
227  * get a reference to a bio, so it won't disappear. the intended use is
228  * something like:
229  *
230  * bio_get(bio);
231  * submit_bio(rw, bio);
232  * if (bio->bi_flags ...)
233  *	do_something
234  * bio_put(bio);
235  *
236  * without the bio_get(), it could potentially complete I/O before submit_bio
237  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
238  * runs
239  */
240 static inline void bio_get(struct bio *bio)
241 {
242 	bio->bi_flags |= (1 << BIO_REFFED);
243 	smp_mb__before_atomic();
244 	atomic_inc(&bio->__bi_cnt);
245 }
246 
247 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
248 {
249 	if (count != 1) {
250 		bio->bi_flags |= (1 << BIO_REFFED);
251 		smp_mb__before_atomic();
252 	}
253 	atomic_set(&bio->__bi_cnt, count);
254 }
255 
256 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
257 {
258 	return (bio->bi_flags & (1U << bit)) != 0;
259 }
260 
261 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
262 {
263 	bio->bi_flags |= (1U << bit);
264 }
265 
266 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
267 {
268 	bio->bi_flags &= ~(1U << bit);
269 }
270 
271 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
272 {
273 	*bv = bio_iovec(bio);
274 }
275 
276 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
277 {
278 	struct bvec_iter iter = bio->bi_iter;
279 	int idx;
280 
281 	if (unlikely(!bio_multiple_segments(bio))) {
282 		*bv = bio_iovec(bio);
283 		return;
284 	}
285 
286 	bio_advance_iter(bio, &iter, iter.bi_size);
287 
288 	if (!iter.bi_bvec_done)
289 		idx = iter.bi_idx - 1;
290 	else	/* in the middle of bvec */
291 		idx = iter.bi_idx;
292 
293 	*bv = bio->bi_io_vec[idx];
294 
295 	/*
296 	 * iter.bi_bvec_done records actual length of the last bvec
297 	 * if this bio ends in the middle of one io vector
298 	 */
299 	if (iter.bi_bvec_done)
300 		bv->bv_len = iter.bi_bvec_done;
301 }
302 
303 enum bip_flags {
304 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
305 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
306 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
307 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
308 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
309 };
310 
311 /*
312  * bio integrity payload
313  */
314 struct bio_integrity_payload {
315 	struct bio		*bip_bio;	/* parent bio */
316 
317 	struct bvec_iter	bip_iter;
318 
319 	unsigned short		bip_slab;	/* slab the bip came from */
320 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
321 	unsigned short		bip_max_vcnt;	/* integrity bio_vec slots */
322 	unsigned short		bip_flags;	/* control flags */
323 
324 	struct work_struct	bip_work;	/* I/O completion */
325 
326 	struct bio_vec		*bip_vec;
327 	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
328 };
329 
330 #if defined(CONFIG_BLK_DEV_INTEGRITY)
331 
332 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
333 {
334 	if (bio->bi_opf & REQ_INTEGRITY)
335 		return bio->bi_integrity;
336 
337 	return NULL;
338 }
339 
340 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
341 {
342 	struct bio_integrity_payload *bip = bio_integrity(bio);
343 
344 	if (bip)
345 		return bip->bip_flags & flag;
346 
347 	return false;
348 }
349 
350 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
351 {
352 	return bip->bip_iter.bi_sector;
353 }
354 
355 static inline void bip_set_seed(struct bio_integrity_payload *bip,
356 				sector_t seed)
357 {
358 	bip->bip_iter.bi_sector = seed;
359 }
360 
361 #endif /* CONFIG_BLK_DEV_INTEGRITY */
362 
363 extern void bio_trim(struct bio *bio, int offset, int size);
364 extern struct bio *bio_split(struct bio *bio, int sectors,
365 			     gfp_t gfp, struct bio_set *bs);
366 
367 /**
368  * bio_next_split - get next @sectors from a bio, splitting if necessary
369  * @bio:	bio to split
370  * @sectors:	number of sectors to split from the front of @bio
371  * @gfp:	gfp mask
372  * @bs:		bio set to allocate from
373  *
374  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
375  * than @sectors, returns the original bio unchanged.
376  */
377 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
378 					 gfp_t gfp, struct bio_set *bs)
379 {
380 	if (sectors >= bio_sectors(bio))
381 		return bio;
382 
383 	return bio_split(bio, sectors, gfp, bs);
384 }
385 
386 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
387 enum {
388 	BIOSET_NEED_BVECS = BIT(0),
389 	BIOSET_NEED_RESCUER = BIT(1),
390 };
391 extern void bioset_free(struct bio_set *);
392 extern mempool_t *biovec_create_pool(int pool_entries);
393 
394 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
395 extern void bio_put(struct bio *);
396 
397 extern void __bio_clone_fast(struct bio *, struct bio *);
398 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
399 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
400 
401 extern struct bio_set *fs_bio_set;
402 
403 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
404 {
405 	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
406 }
407 
408 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
409 {
410 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
411 }
412 
413 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
414 {
415 	return bio_clone_bioset(bio, gfp_mask, NULL);
416 
417 }
418 
419 extern blk_qc_t submit_bio(struct bio *);
420 
421 extern void bio_endio(struct bio *);
422 
423 static inline void bio_io_error(struct bio *bio)
424 {
425 	bio->bi_status = BLK_STS_IOERR;
426 	bio_endio(bio);
427 }
428 
429 static inline void bio_wouldblock_error(struct bio *bio)
430 {
431 	bio->bi_status = BLK_STS_AGAIN;
432 	bio_endio(bio);
433 }
434 
435 struct request_queue;
436 extern int bio_phys_segments(struct request_queue *, struct bio *);
437 
438 extern int submit_bio_wait(struct bio *bio);
439 extern void bio_advance(struct bio *, unsigned);
440 
441 extern void bio_init(struct bio *bio, struct bio_vec *table,
442 		     unsigned short max_vecs);
443 extern void bio_uninit(struct bio *);
444 extern void bio_reset(struct bio *);
445 void bio_chain(struct bio *, struct bio *);
446 
447 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
448 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
449 			   unsigned int, unsigned int);
450 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
451 struct rq_map_data;
452 extern struct bio *bio_map_user_iov(struct request_queue *,
453 				    struct iov_iter *, gfp_t);
454 extern void bio_unmap_user(struct bio *);
455 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
456 				gfp_t);
457 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
458 				 gfp_t, int);
459 extern void bio_set_pages_dirty(struct bio *bio);
460 extern void bio_check_pages_dirty(struct bio *bio);
461 
462 void generic_start_io_acct(struct request_queue *q, int rw,
463 				unsigned long sectors, struct hd_struct *part);
464 void generic_end_io_acct(struct request_queue *q, int rw,
465 				struct hd_struct *part,
466 				unsigned long start_time);
467 
468 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
469 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
470 #endif
471 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
472 extern void bio_flush_dcache_pages(struct bio *bi);
473 #else
474 static inline void bio_flush_dcache_pages(struct bio *bi)
475 {
476 }
477 #endif
478 
479 extern void bio_copy_data(struct bio *dst, struct bio *src);
480 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
481 extern void bio_free_pages(struct bio *bio);
482 
483 extern struct bio *bio_copy_user_iov(struct request_queue *,
484 				     struct rq_map_data *,
485 				     struct iov_iter *,
486 				     gfp_t);
487 extern int bio_uncopy_user(struct bio *);
488 void zero_fill_bio(struct bio *bio);
489 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
490 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
491 extern unsigned int bvec_nr_vecs(unsigned short idx);
492 
493 #define bio_set_dev(bio, bdev) 			\
494 do {						\
495 	(bio)->bi_disk = (bdev)->bd_disk;	\
496 	(bio)->bi_partno = (bdev)->bd_partno;	\
497 } while (0)
498 
499 #define bio_copy_dev(dst, src)			\
500 do {						\
501 	(dst)->bi_disk = (src)->bi_disk;	\
502 	(dst)->bi_partno = (src)->bi_partno;	\
503 } while (0)
504 
505 #define bio_dev(bio) \
506 	disk_devt((bio)->bi_disk)
507 
508 #define bio_devname(bio, buf) \
509 	__bdevname(bio_dev(bio), (buf))
510 
511 #ifdef CONFIG_BLK_CGROUP
512 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
513 void bio_disassociate_task(struct bio *bio);
514 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
515 #else	/* CONFIG_BLK_CGROUP */
516 static inline int bio_associate_blkcg(struct bio *bio,
517 			struct cgroup_subsys_state *blkcg_css) { return 0; }
518 static inline void bio_disassociate_task(struct bio *bio) { }
519 static inline void bio_clone_blkcg_association(struct bio *dst,
520 			struct bio *src) { }
521 #endif	/* CONFIG_BLK_CGROUP */
522 
523 #ifdef CONFIG_HIGHMEM
524 /*
525  * remember never ever reenable interrupts between a bvec_kmap_irq and
526  * bvec_kunmap_irq!
527  */
528 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
529 {
530 	unsigned long addr;
531 
532 	/*
533 	 * might not be a highmem page, but the preempt/irq count
534 	 * balancing is a lot nicer this way
535 	 */
536 	local_irq_save(*flags);
537 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
538 
539 	BUG_ON(addr & ~PAGE_MASK);
540 
541 	return (char *) addr + bvec->bv_offset;
542 }
543 
544 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
545 {
546 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
547 
548 	kunmap_atomic((void *) ptr);
549 	local_irq_restore(*flags);
550 }
551 
552 #else
553 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
554 {
555 	return page_address(bvec->bv_page) + bvec->bv_offset;
556 }
557 
558 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
559 {
560 	*flags = 0;
561 }
562 #endif
563 
564 /*
565  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
566  *
567  * A bio_list anchors a singly-linked list of bios chained through the bi_next
568  * member of the bio.  The bio_list also caches the last list member to allow
569  * fast access to the tail.
570  */
571 struct bio_list {
572 	struct bio *head;
573 	struct bio *tail;
574 };
575 
576 static inline int bio_list_empty(const struct bio_list *bl)
577 {
578 	return bl->head == NULL;
579 }
580 
581 static inline void bio_list_init(struct bio_list *bl)
582 {
583 	bl->head = bl->tail = NULL;
584 }
585 
586 #define BIO_EMPTY_LIST	{ NULL, NULL }
587 
588 #define bio_list_for_each(bio, bl) \
589 	for (bio = (bl)->head; bio; bio = bio->bi_next)
590 
591 static inline unsigned bio_list_size(const struct bio_list *bl)
592 {
593 	unsigned sz = 0;
594 	struct bio *bio;
595 
596 	bio_list_for_each(bio, bl)
597 		sz++;
598 
599 	return sz;
600 }
601 
602 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
603 {
604 	bio->bi_next = NULL;
605 
606 	if (bl->tail)
607 		bl->tail->bi_next = bio;
608 	else
609 		bl->head = bio;
610 
611 	bl->tail = bio;
612 }
613 
614 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
615 {
616 	bio->bi_next = bl->head;
617 
618 	bl->head = bio;
619 
620 	if (!bl->tail)
621 		bl->tail = bio;
622 }
623 
624 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
625 {
626 	if (!bl2->head)
627 		return;
628 
629 	if (bl->tail)
630 		bl->tail->bi_next = bl2->head;
631 	else
632 		bl->head = bl2->head;
633 
634 	bl->tail = bl2->tail;
635 }
636 
637 static inline void bio_list_merge_head(struct bio_list *bl,
638 				       struct bio_list *bl2)
639 {
640 	if (!bl2->head)
641 		return;
642 
643 	if (bl->head)
644 		bl2->tail->bi_next = bl->head;
645 	else
646 		bl->tail = bl2->tail;
647 
648 	bl->head = bl2->head;
649 }
650 
651 static inline struct bio *bio_list_peek(struct bio_list *bl)
652 {
653 	return bl->head;
654 }
655 
656 static inline struct bio *bio_list_pop(struct bio_list *bl)
657 {
658 	struct bio *bio = bl->head;
659 
660 	if (bio) {
661 		bl->head = bl->head->bi_next;
662 		if (!bl->head)
663 			bl->tail = NULL;
664 
665 		bio->bi_next = NULL;
666 	}
667 
668 	return bio;
669 }
670 
671 static inline struct bio *bio_list_get(struct bio_list *bl)
672 {
673 	struct bio *bio = bl->head;
674 
675 	bl->head = bl->tail = NULL;
676 
677 	return bio;
678 }
679 
680 /*
681  * Increment chain count for the bio. Make sure the CHAIN flag update
682  * is visible before the raised count.
683  */
684 static inline void bio_inc_remaining(struct bio *bio)
685 {
686 	bio_set_flag(bio, BIO_CHAIN);
687 	smp_mb__before_atomic();
688 	atomic_inc(&bio->__bi_remaining);
689 }
690 
691 /*
692  * bio_set is used to allow other portions of the IO system to
693  * allocate their own private memory pools for bio and iovec structures.
694  * These memory pools in turn all allocate from the bio_slab
695  * and the bvec_slabs[].
696  */
697 #define BIO_POOL_SIZE 2
698 
699 struct bio_set {
700 	struct kmem_cache *bio_slab;
701 	unsigned int front_pad;
702 
703 	mempool_t *bio_pool;
704 	mempool_t *bvec_pool;
705 #if defined(CONFIG_BLK_DEV_INTEGRITY)
706 	mempool_t *bio_integrity_pool;
707 	mempool_t *bvec_integrity_pool;
708 #endif
709 
710 	/*
711 	 * Deadlock avoidance for stacking block drivers: see comments in
712 	 * bio_alloc_bioset() for details
713 	 */
714 	spinlock_t		rescue_lock;
715 	struct bio_list		rescue_list;
716 	struct work_struct	rescue_work;
717 	struct workqueue_struct	*rescue_workqueue;
718 };
719 
720 struct biovec_slab {
721 	int nr_vecs;
722 	char *name;
723 	struct kmem_cache *slab;
724 };
725 
726 /*
727  * a small number of entries is fine, not going to be performance critical.
728  * basically we just need to survive
729  */
730 #define BIO_SPLIT_ENTRIES 2
731 
732 #if defined(CONFIG_BLK_DEV_INTEGRITY)
733 
734 #define bip_for_each_vec(bvl, bip, iter)				\
735 	for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
736 
737 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
738 	for_each_bio(_bio)						\
739 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
740 
741 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
742 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
743 extern bool bio_integrity_prep(struct bio *);
744 extern void bio_integrity_advance(struct bio *, unsigned int);
745 extern void bio_integrity_trim(struct bio *);
746 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
747 extern int bioset_integrity_create(struct bio_set *, int);
748 extern void bioset_integrity_free(struct bio_set *);
749 extern void bio_integrity_init(void);
750 
751 #else /* CONFIG_BLK_DEV_INTEGRITY */
752 
753 static inline void *bio_integrity(struct bio *bio)
754 {
755 	return NULL;
756 }
757 
758 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
759 {
760 	return 0;
761 }
762 
763 static inline void bioset_integrity_free (struct bio_set *bs)
764 {
765 	return;
766 }
767 
768 static inline bool bio_integrity_prep(struct bio *bio)
769 {
770 	return true;
771 }
772 
773 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
774 				      gfp_t gfp_mask)
775 {
776 	return 0;
777 }
778 
779 static inline void bio_integrity_advance(struct bio *bio,
780 					 unsigned int bytes_done)
781 {
782 	return;
783 }
784 
785 static inline void bio_integrity_trim(struct bio *bio)
786 {
787 	return;
788 }
789 
790 static inline void bio_integrity_init(void)
791 {
792 	return;
793 }
794 
795 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
796 {
797 	return false;
798 }
799 
800 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
801 								unsigned int nr)
802 {
803 	return ERR_PTR(-EINVAL);
804 }
805 
806 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
807 					unsigned int len, unsigned int offset)
808 {
809 	return 0;
810 }
811 
812 #endif /* CONFIG_BLK_DEV_INTEGRITY */
813 
814 #endif /* CONFIG_BLOCK */
815 #endif /* __LINUX_BIO_H */
816