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1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
4  */
5 #ifndef __LINUX_BIO_H
6 #define __LINUX_BIO_H
7 
8 #include <linux/highmem.h>
9 #include <linux/mempool.h>
10 #include <linux/ioprio.h>
11 #include <linux/bio-crypt-ctx.h>
12 
13 #ifdef CONFIG_BLOCK
14 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
15 #include <linux/blk_types.h>
16 
17 #define BIO_DEBUG
18 
19 #ifdef BIO_DEBUG
20 #define BIO_BUG_ON	BUG_ON
21 #else
22 #define BIO_BUG_ON
23 #endif
24 
25 #define BIO_MAX_PAGES		256
26 
27 #define bio_prio(bio)			(bio)->bi_ioprio
28 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
29 
30 #define bio_iter_iovec(bio, iter)				\
31 	bvec_iter_bvec((bio)->bi_io_vec, (iter))
32 
33 #define bio_iter_page(bio, iter)				\
34 	bvec_iter_page((bio)->bi_io_vec, (iter))
35 #define bio_iter_len(bio, iter)					\
36 	bvec_iter_len((bio)->bi_io_vec, (iter))
37 #define bio_iter_offset(bio, iter)				\
38 	bvec_iter_offset((bio)->bi_io_vec, (iter))
39 
40 #define bio_page(bio)		bio_iter_page((bio), (bio)->bi_iter)
41 #define bio_offset(bio)		bio_iter_offset((bio), (bio)->bi_iter)
42 #define bio_iovec(bio)		bio_iter_iovec((bio), (bio)->bi_iter)
43 
44 #define bio_multiple_segments(bio)				\
45 	((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
46 
47 #define bvec_iter_sectors(iter)	((iter).bi_size >> 9)
48 #define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
49 
50 #define bio_sectors(bio)	bvec_iter_sectors((bio)->bi_iter)
51 #define bio_end_sector(bio)	bvec_iter_end_sector((bio)->bi_iter)
52 
53 /*
54  * Return the data direction, READ or WRITE.
55  */
56 #define bio_data_dir(bio) \
57 	(op_is_write(bio_op(bio)) ? WRITE : READ)
58 
59 /*
60  * Check whether this bio carries any data or not. A NULL bio is allowed.
61  */
bio_has_data(struct bio * bio)62 static inline bool bio_has_data(struct bio *bio)
63 {
64 	if (bio &&
65 	    bio->bi_iter.bi_size &&
66 	    bio_op(bio) != REQ_OP_DISCARD &&
67 	    bio_op(bio) != REQ_OP_SECURE_ERASE &&
68 	    bio_op(bio) != REQ_OP_WRITE_ZEROES)
69 		return true;
70 
71 	return false;
72 }
73 
bio_no_advance_iter(struct bio * bio)74 static inline bool bio_no_advance_iter(struct bio *bio)
75 {
76 	return bio_op(bio) == REQ_OP_DISCARD ||
77 	       bio_op(bio) == REQ_OP_SECURE_ERASE ||
78 	       bio_op(bio) == REQ_OP_WRITE_SAME ||
79 	       bio_op(bio) == REQ_OP_WRITE_ZEROES;
80 }
81 
bio_mergeable(struct bio * bio)82 static inline bool bio_mergeable(struct bio *bio)
83 {
84 	if (bio->bi_opf & REQ_NOMERGE_FLAGS)
85 		return false;
86 
87 	return true;
88 }
89 
bio_cur_bytes(struct bio * bio)90 static inline unsigned int bio_cur_bytes(struct bio *bio)
91 {
92 	if (bio_has_data(bio))
93 		return bio_iovec(bio).bv_len;
94 	else /* dataless requests such as discard */
95 		return bio->bi_iter.bi_size;
96 }
97 
bio_data(struct bio * bio)98 static inline void *bio_data(struct bio *bio)
99 {
100 	if (bio_has_data(bio))
101 		return page_address(bio_page(bio)) + bio_offset(bio);
102 
103 	return NULL;
104 }
105 
106 /**
107  * bio_full - check if the bio is full
108  * @bio:	bio to check
109  * @len:	length of one segment to be added
110  *
111  * Return true if @bio is full and one segment with @len bytes can't be
112  * added to the bio, otherwise return false
113  */
bio_full(struct bio * bio,unsigned len)114 static inline bool bio_full(struct bio *bio, unsigned len)
115 {
116 	if (bio->bi_vcnt >= bio->bi_max_vecs)
117 		return true;
118 
119 	if (bio->bi_iter.bi_size > UINT_MAX - len)
120 		return true;
121 
122 	return false;
123 }
124 
bio_next_segment(const struct bio * bio,struct bvec_iter_all * iter)125 static inline bool bio_next_segment(const struct bio *bio,
126 				    struct bvec_iter_all *iter)
127 {
128 	if (iter->idx >= bio->bi_vcnt)
129 		return false;
130 
131 	bvec_advance(&bio->bi_io_vec[iter->idx], iter);
132 	return true;
133 }
134 
135 /*
136  * drivers should _never_ use the all version - the bio may have been split
137  * before it got to the driver and the driver won't own all of it
138  */
139 #define bio_for_each_segment_all(bvl, bio, iter) \
140 	for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
141 
bio_advance_iter(struct bio * bio,struct bvec_iter * iter,unsigned bytes)142 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
143 				    unsigned bytes)
144 {
145 	iter->bi_sector += bytes >> 9;
146 
147 	if (bio_no_advance_iter(bio))
148 		iter->bi_size -= bytes;
149 	else
150 		bvec_iter_advance(bio->bi_io_vec, iter, bytes);
151 		/* TODO: It is reasonable to complete bio with error here. */
152 }
153 
154 #define __bio_for_each_segment(bvl, bio, iter, start)			\
155 	for (iter = (start);						\
156 	     (iter).bi_size &&						\
157 		((bvl = bio_iter_iovec((bio), (iter))), 1);		\
158 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
159 
160 #define bio_for_each_segment(bvl, bio, iter)				\
161 	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
162 
163 #define __bio_for_each_bvec(bvl, bio, iter, start)		\
164 	for (iter = (start);						\
165 	     (iter).bi_size &&						\
166 		((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
167 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
168 
169 /* iterate over multi-page bvec */
170 #define bio_for_each_bvec(bvl, bio, iter)			\
171 	__bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
172 
173 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
174 
bio_segments(struct bio * bio)175 static inline unsigned bio_segments(struct bio *bio)
176 {
177 	unsigned segs = 0;
178 	struct bio_vec bv;
179 	struct bvec_iter iter;
180 
181 	/*
182 	 * We special case discard/write same/write zeroes, because they
183 	 * interpret bi_size differently:
184 	 */
185 
186 	switch (bio_op(bio)) {
187 	case REQ_OP_DISCARD:
188 	case REQ_OP_SECURE_ERASE:
189 	case REQ_OP_WRITE_ZEROES:
190 		return 0;
191 	case REQ_OP_WRITE_SAME:
192 		return 1;
193 	default:
194 		break;
195 	}
196 
197 	bio_for_each_segment(bv, bio, iter)
198 		segs++;
199 
200 	return segs;
201 }
202 
203 /*
204  * get a reference to a bio, so it won't disappear. the intended use is
205  * something like:
206  *
207  * bio_get(bio);
208  * submit_bio(rw, bio);
209  * if (bio->bi_flags ...)
210  *	do_something
211  * bio_put(bio);
212  *
213  * without the bio_get(), it could potentially complete I/O before submit_bio
214  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
215  * runs
216  */
bio_get(struct bio * bio)217 static inline void bio_get(struct bio *bio)
218 {
219 	bio->bi_flags |= (1 << BIO_REFFED);
220 	smp_mb__before_atomic();
221 	atomic_inc(&bio->__bi_cnt);
222 }
223 
bio_cnt_set(struct bio * bio,unsigned int count)224 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
225 {
226 	if (count != 1) {
227 		bio->bi_flags |= (1 << BIO_REFFED);
228 		smp_mb();
229 	}
230 	atomic_set(&bio->__bi_cnt, count);
231 }
232 
bio_flagged(struct bio * bio,unsigned int bit)233 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
234 {
235 	return (bio->bi_flags & (1U << bit)) != 0;
236 }
237 
bio_set_flag(struct bio * bio,unsigned int bit)238 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
239 {
240 	bio->bi_flags |= (1U << bit);
241 }
242 
bio_clear_flag(struct bio * bio,unsigned int bit)243 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
244 {
245 	bio->bi_flags &= ~(1U << bit);
246 }
247 
bio_get_first_bvec(struct bio * bio,struct bio_vec * bv)248 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
249 {
250 	*bv = bio_iovec(bio);
251 }
252 
bio_get_last_bvec(struct bio * bio,struct bio_vec * bv)253 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
254 {
255 	struct bvec_iter iter = bio->bi_iter;
256 	int idx;
257 
258 	if (unlikely(!bio_multiple_segments(bio))) {
259 		*bv = bio_iovec(bio);
260 		return;
261 	}
262 
263 	bio_advance_iter(bio, &iter, iter.bi_size);
264 
265 	if (!iter.bi_bvec_done)
266 		idx = iter.bi_idx - 1;
267 	else	/* in the middle of bvec */
268 		idx = iter.bi_idx;
269 
270 	*bv = bio->bi_io_vec[idx];
271 
272 	/*
273 	 * iter.bi_bvec_done records actual length of the last bvec
274 	 * if this bio ends in the middle of one io vector
275 	 */
276 	if (iter.bi_bvec_done)
277 		bv->bv_len = iter.bi_bvec_done;
278 }
279 
bio_first_bvec_all(struct bio * bio)280 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
281 {
282 	WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
283 	return bio->bi_io_vec;
284 }
285 
bio_first_page_all(struct bio * bio)286 static inline struct page *bio_first_page_all(struct bio *bio)
287 {
288 	return bio_first_bvec_all(bio)->bv_page;
289 }
290 
bio_last_bvec_all(struct bio * bio)291 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
292 {
293 	WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
294 	return &bio->bi_io_vec[bio->bi_vcnt - 1];
295 }
296 
297 enum bip_flags {
298 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
299 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
300 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
301 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
302 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
303 };
304 
305 /*
306  * bio integrity payload
307  */
308 struct bio_integrity_payload {
309 	struct bio		*bip_bio;	/* parent bio */
310 
311 	struct bvec_iter	bip_iter;
312 
313 	unsigned short		bip_slab;	/* slab the bip came from */
314 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
315 	unsigned short		bip_max_vcnt;	/* integrity bio_vec slots */
316 	unsigned short		bip_flags;	/* control flags */
317 
318 	struct bvec_iter	bio_iter;	/* for rewinding parent bio */
319 
320 	struct work_struct	bip_work;	/* I/O completion */
321 
322 	struct bio_vec		*bip_vec;
323 	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
324 };
325 
326 #if defined(CONFIG_BLK_DEV_INTEGRITY)
327 
bio_integrity(struct bio * bio)328 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
329 {
330 	if (bio->bi_opf & REQ_INTEGRITY)
331 		return bio->bi_integrity;
332 
333 	return NULL;
334 }
335 
bio_integrity_flagged(struct bio * bio,enum bip_flags flag)336 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
337 {
338 	struct bio_integrity_payload *bip = bio_integrity(bio);
339 
340 	if (bip)
341 		return bip->bip_flags & flag;
342 
343 	return false;
344 }
345 
bip_get_seed(struct bio_integrity_payload * bip)346 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
347 {
348 	return bip->bip_iter.bi_sector;
349 }
350 
bip_set_seed(struct bio_integrity_payload * bip,sector_t seed)351 static inline void bip_set_seed(struct bio_integrity_payload *bip,
352 				sector_t seed)
353 {
354 	bip->bip_iter.bi_sector = seed;
355 }
356 
357 #endif /* CONFIG_BLK_DEV_INTEGRITY */
358 
359 extern void bio_trim(struct bio *bio, int offset, int size);
360 extern struct bio *bio_split(struct bio *bio, int sectors,
361 			     gfp_t gfp, struct bio_set *bs);
362 
363 /**
364  * bio_next_split - get next @sectors from a bio, splitting if necessary
365  * @bio:	bio to split
366  * @sectors:	number of sectors to split from the front of @bio
367  * @gfp:	gfp mask
368  * @bs:		bio set to allocate from
369  *
370  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
371  * than @sectors, returns the original bio unchanged.
372  */
bio_next_split(struct bio * bio,int sectors,gfp_t gfp,struct bio_set * bs)373 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
374 					 gfp_t gfp, struct bio_set *bs)
375 {
376 	if (sectors >= bio_sectors(bio))
377 		return bio;
378 
379 	return bio_split(bio, sectors, gfp, bs);
380 }
381 
382 enum {
383 	BIOSET_NEED_BVECS = BIT(0),
384 	BIOSET_NEED_RESCUER = BIT(1),
385 };
386 extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
387 extern void bioset_exit(struct bio_set *);
388 extern int biovec_init_pool(mempool_t *pool, int pool_entries);
389 extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
390 
391 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
392 extern void bio_put(struct bio *);
393 
394 extern void __bio_clone_fast(struct bio *, struct bio *);
395 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
396 
397 extern struct bio_set fs_bio_set;
398 
bio_alloc(gfp_t gfp_mask,unsigned int nr_iovecs)399 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
400 {
401 	return bio_alloc_bioset(gfp_mask, nr_iovecs, &fs_bio_set);
402 }
403 
bio_kmalloc(gfp_t gfp_mask,unsigned int nr_iovecs)404 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
405 {
406 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
407 }
408 
409 extern blk_qc_t submit_bio(struct bio *);
410 
411 extern void bio_endio(struct bio *);
412 
bio_io_error(struct bio * bio)413 static inline void bio_io_error(struct bio *bio)
414 {
415 	bio->bi_status = BLK_STS_IOERR;
416 	bio_endio(bio);
417 }
418 
bio_wouldblock_error(struct bio * bio)419 static inline void bio_wouldblock_error(struct bio *bio)
420 {
421 	bio->bi_status = BLK_STS_AGAIN;
422 	bio_endio(bio);
423 }
424 
425 struct request_queue;
426 
427 extern int submit_bio_wait(struct bio *bio);
428 extern void bio_advance(struct bio *, unsigned);
429 
430 extern void bio_init(struct bio *bio, struct bio_vec *table,
431 		     unsigned short max_vecs);
432 extern void bio_uninit(struct bio *);
433 extern void bio_reset(struct bio *);
434 void bio_chain(struct bio *, struct bio *);
435 
436 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
437 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
438 			   unsigned int, unsigned int);
439 bool __bio_try_merge_page(struct bio *bio, struct page *page,
440 		unsigned int len, unsigned int off, bool *same_page);
441 void __bio_add_page(struct bio *bio, struct page *page,
442 		unsigned int len, unsigned int off);
443 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
444 void bio_release_pages(struct bio *bio, bool mark_dirty);
445 struct rq_map_data;
446 extern struct bio *bio_map_user_iov(struct request_queue *,
447 				    struct iov_iter *, gfp_t);
448 extern void bio_unmap_user(struct bio *);
449 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
450 				gfp_t);
451 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
452 				 gfp_t, int);
453 extern void bio_set_pages_dirty(struct bio *bio);
454 extern void bio_check_pages_dirty(struct bio *bio);
455 
456 void generic_start_io_acct(struct request_queue *q, int op,
457 				unsigned long sectors, struct hd_struct *part);
458 void generic_end_io_acct(struct request_queue *q, int op,
459 				struct hd_struct *part,
460 				unsigned long start_time);
461 
462 extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
463 			       struct bio *src, struct bvec_iter *src_iter);
464 extern void bio_copy_data(struct bio *dst, struct bio *src);
465 extern void bio_list_copy_data(struct bio *dst, struct bio *src);
466 extern void bio_free_pages(struct bio *bio);
467 
468 extern struct bio *bio_copy_user_iov(struct request_queue *,
469 				     struct rq_map_data *,
470 				     struct iov_iter *,
471 				     gfp_t);
472 extern int bio_uncopy_user(struct bio *);
473 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
474 void bio_truncate(struct bio *bio, unsigned new_size);
475 
zero_fill_bio(struct bio * bio)476 static inline void zero_fill_bio(struct bio *bio)
477 {
478 	zero_fill_bio_iter(bio, bio->bi_iter);
479 }
480 
481 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
482 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
483 extern unsigned int bvec_nr_vecs(unsigned short idx);
484 extern const char *bio_devname(struct bio *bio, char *buffer);
485 
486 #define bio_set_dev(bio, bdev) 			\
487 do {						\
488 	if ((bio)->bi_disk != (bdev)->bd_disk)	\
489 		bio_clear_flag(bio, BIO_THROTTLED);\
490 	(bio)->bi_disk = (bdev)->bd_disk;	\
491 	(bio)->bi_partno = (bdev)->bd_partno;	\
492 	bio_associate_blkg(bio);		\
493 } while (0)
494 
495 #define bio_copy_dev(dst, src)			\
496 do {						\
497 	(dst)->bi_disk = (src)->bi_disk;	\
498 	(dst)->bi_partno = (src)->bi_partno;	\
499 	bio_clone_blkg_association(dst, src);	\
500 } while (0)
501 
502 #define bio_dev(bio) \
503 	disk_devt((bio)->bi_disk)
504 
505 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
506 void bio_associate_blkg_from_page(struct bio *bio, struct page *page);
507 #else
bio_associate_blkg_from_page(struct bio * bio,struct page * page)508 static inline void bio_associate_blkg_from_page(struct bio *bio,
509 						struct page *page) { }
510 #endif
511 
512 #ifdef CONFIG_BLK_CGROUP
513 void bio_disassociate_blkg(struct bio *bio);
514 void bio_associate_blkg(struct bio *bio);
515 void bio_associate_blkg_from_css(struct bio *bio,
516 				 struct cgroup_subsys_state *css);
517 void bio_clone_blkg_association(struct bio *dst, struct bio *src);
518 #else	/* CONFIG_BLK_CGROUP */
bio_disassociate_blkg(struct bio * bio)519 static inline void bio_disassociate_blkg(struct bio *bio) { }
bio_associate_blkg(struct bio * bio)520 static inline void bio_associate_blkg(struct bio *bio) { }
bio_associate_blkg_from_css(struct bio * bio,struct cgroup_subsys_state * css)521 static inline void bio_associate_blkg_from_css(struct bio *bio,
522 					       struct cgroup_subsys_state *css)
523 { }
bio_clone_blkg_association(struct bio * dst,struct bio * src)524 static inline void bio_clone_blkg_association(struct bio *dst,
525 					      struct bio *src) { }
526 #endif	/* CONFIG_BLK_CGROUP */
527 
528 #ifdef CONFIG_HIGHMEM
529 /*
530  * remember never ever reenable interrupts between a bvec_kmap_irq and
531  * bvec_kunmap_irq!
532  */
bvec_kmap_irq(struct bio_vec * bvec,unsigned long * flags)533 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
534 {
535 	unsigned long addr;
536 
537 	/*
538 	 * might not be a highmem page, but the preempt/irq count
539 	 * balancing is a lot nicer this way
540 	 */
541 	local_irq_save(*flags);
542 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
543 
544 	BUG_ON(addr & ~PAGE_MASK);
545 
546 	return (char *) addr + bvec->bv_offset;
547 }
548 
bvec_kunmap_irq(char * buffer,unsigned long * flags)549 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
550 {
551 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
552 
553 	kunmap_atomic((void *) ptr);
554 	local_irq_restore(*flags);
555 }
556 
557 #else
bvec_kmap_irq(struct bio_vec * bvec,unsigned long * flags)558 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
559 {
560 	return page_address(bvec->bv_page) + bvec->bv_offset;
561 }
562 
bvec_kunmap_irq(char * buffer,unsigned long * flags)563 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
564 {
565 	*flags = 0;
566 }
567 #endif
568 
569 /*
570  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
571  *
572  * A bio_list anchors a singly-linked list of bios chained through the bi_next
573  * member of the bio.  The bio_list also caches the last list member to allow
574  * fast access to the tail.
575  */
576 struct bio_list {
577 	struct bio *head;
578 	struct bio *tail;
579 };
580 
bio_list_empty(const struct bio_list * bl)581 static inline int bio_list_empty(const struct bio_list *bl)
582 {
583 	return bl->head == NULL;
584 }
585 
bio_list_init(struct bio_list * bl)586 static inline void bio_list_init(struct bio_list *bl)
587 {
588 	bl->head = bl->tail = NULL;
589 }
590 
591 #define BIO_EMPTY_LIST	{ NULL, NULL }
592 
593 #define bio_list_for_each(bio, bl) \
594 	for (bio = (bl)->head; bio; bio = bio->bi_next)
595 
bio_list_size(const struct bio_list * bl)596 static inline unsigned bio_list_size(const struct bio_list *bl)
597 {
598 	unsigned sz = 0;
599 	struct bio *bio;
600 
601 	bio_list_for_each(bio, bl)
602 		sz++;
603 
604 	return sz;
605 }
606 
bio_list_add(struct bio_list * bl,struct bio * bio)607 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
608 {
609 	bio->bi_next = NULL;
610 
611 	if (bl->tail)
612 		bl->tail->bi_next = bio;
613 	else
614 		bl->head = bio;
615 
616 	bl->tail = bio;
617 }
618 
bio_list_add_head(struct bio_list * bl,struct bio * bio)619 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
620 {
621 	bio->bi_next = bl->head;
622 
623 	bl->head = bio;
624 
625 	if (!bl->tail)
626 		bl->tail = bio;
627 }
628 
bio_list_merge(struct bio_list * bl,struct bio_list * bl2)629 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
630 {
631 	if (!bl2->head)
632 		return;
633 
634 	if (bl->tail)
635 		bl->tail->bi_next = bl2->head;
636 	else
637 		bl->head = bl2->head;
638 
639 	bl->tail = bl2->tail;
640 }
641 
bio_list_merge_head(struct bio_list * bl,struct bio_list * bl2)642 static inline void bio_list_merge_head(struct bio_list *bl,
643 				       struct bio_list *bl2)
644 {
645 	if (!bl2->head)
646 		return;
647 
648 	if (bl->head)
649 		bl2->tail->bi_next = bl->head;
650 	else
651 		bl->tail = bl2->tail;
652 
653 	bl->head = bl2->head;
654 }
655 
bio_list_peek(struct bio_list * bl)656 static inline struct bio *bio_list_peek(struct bio_list *bl)
657 {
658 	return bl->head;
659 }
660 
bio_list_pop(struct bio_list * bl)661 static inline struct bio *bio_list_pop(struct bio_list *bl)
662 {
663 	struct bio *bio = bl->head;
664 
665 	if (bio) {
666 		bl->head = bl->head->bi_next;
667 		if (!bl->head)
668 			bl->tail = NULL;
669 
670 		bio->bi_next = NULL;
671 	}
672 
673 	return bio;
674 }
675 
bio_list_get(struct bio_list * bl)676 static inline struct bio *bio_list_get(struct bio_list *bl)
677 {
678 	struct bio *bio = bl->head;
679 
680 	bl->head = bl->tail = NULL;
681 
682 	return bio;
683 }
684 
685 /*
686  * Increment chain count for the bio. Make sure the CHAIN flag update
687  * is visible before the raised count.
688  */
bio_inc_remaining(struct bio * bio)689 static inline void bio_inc_remaining(struct bio *bio)
690 {
691 	bio_set_flag(bio, BIO_CHAIN);
692 	smp_mb__before_atomic();
693 	atomic_inc(&bio->__bi_remaining);
694 }
695 
696 /*
697  * bio_set is used to allow other portions of the IO system to
698  * allocate their own private memory pools for bio and iovec structures.
699  * These memory pools in turn all allocate from the bio_slab
700  * and the bvec_slabs[].
701  */
702 #define BIO_POOL_SIZE 2
703 
704 struct bio_set {
705 	struct kmem_cache *bio_slab;
706 	unsigned int front_pad;
707 
708 	mempool_t bio_pool;
709 	mempool_t bvec_pool;
710 #if defined(CONFIG_BLK_DEV_INTEGRITY)
711 	mempool_t bio_integrity_pool;
712 	mempool_t bvec_integrity_pool;
713 #endif
714 
715 	/*
716 	 * Deadlock avoidance for stacking block drivers: see comments in
717 	 * bio_alloc_bioset() for details
718 	 */
719 	spinlock_t		rescue_lock;
720 	struct bio_list		rescue_list;
721 	struct work_struct	rescue_work;
722 	struct workqueue_struct	*rescue_workqueue;
723 };
724 
725 struct biovec_slab {
726 	int nr_vecs;
727 	char *name;
728 	struct kmem_cache *slab;
729 };
730 
bioset_initialized(struct bio_set * bs)731 static inline bool bioset_initialized(struct bio_set *bs)
732 {
733 	return bs->bio_slab != NULL;
734 }
735 
736 /*
737  * a small number of entries is fine, not going to be performance critical.
738  * basically we just need to survive
739  */
740 #define BIO_SPLIT_ENTRIES 2
741 
742 #if defined(CONFIG_BLK_DEV_INTEGRITY)
743 
744 #define bip_for_each_vec(bvl, bip, iter)				\
745 	for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
746 
747 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
748 	for_each_bio(_bio)						\
749 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
750 
751 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
752 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
753 extern bool bio_integrity_prep(struct bio *);
754 extern void bio_integrity_advance(struct bio *, unsigned int);
755 extern void bio_integrity_trim(struct bio *);
756 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
757 extern int bioset_integrity_create(struct bio_set *, int);
758 extern void bioset_integrity_free(struct bio_set *);
759 extern void bio_integrity_init(void);
760 
761 #else /* CONFIG_BLK_DEV_INTEGRITY */
762 
bio_integrity(struct bio * bio)763 static inline void *bio_integrity(struct bio *bio)
764 {
765 	return NULL;
766 }
767 
bioset_integrity_create(struct bio_set * bs,int pool_size)768 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
769 {
770 	return 0;
771 }
772 
bioset_integrity_free(struct bio_set * bs)773 static inline void bioset_integrity_free (struct bio_set *bs)
774 {
775 	return;
776 }
777 
bio_integrity_prep(struct bio * bio)778 static inline bool bio_integrity_prep(struct bio *bio)
779 {
780 	return true;
781 }
782 
bio_integrity_clone(struct bio * bio,struct bio * bio_src,gfp_t gfp_mask)783 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
784 				      gfp_t gfp_mask)
785 {
786 	return 0;
787 }
788 
bio_integrity_advance(struct bio * bio,unsigned int bytes_done)789 static inline void bio_integrity_advance(struct bio *bio,
790 					 unsigned int bytes_done)
791 {
792 	return;
793 }
794 
bio_integrity_trim(struct bio * bio)795 static inline void bio_integrity_trim(struct bio *bio)
796 {
797 	return;
798 }
799 
bio_integrity_init(void)800 static inline void bio_integrity_init(void)
801 {
802 	return;
803 }
804 
bio_integrity_flagged(struct bio * bio,enum bip_flags flag)805 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
806 {
807 	return false;
808 }
809 
bio_integrity_alloc(struct bio * bio,gfp_t gfp,unsigned int nr)810 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
811 								unsigned int nr)
812 {
813 	return ERR_PTR(-EINVAL);
814 }
815 
bio_integrity_add_page(struct bio * bio,struct page * page,unsigned int len,unsigned int offset)816 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
817 					unsigned int len, unsigned int offset)
818 {
819 	return 0;
820 }
821 
822 #endif /* CONFIG_BLK_DEV_INTEGRITY */
823 
824 /*
825  * Mark a bio as polled. Note that for async polled IO, the caller must
826  * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
827  * We cannot block waiting for requests on polled IO, as those completions
828  * must be found by the caller. This is different than IRQ driven IO, where
829  * it's safe to wait for IO to complete.
830  */
bio_set_polled(struct bio * bio,struct kiocb * kiocb)831 static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
832 {
833 	bio->bi_opf |= REQ_HIPRI;
834 	if (!is_sync_kiocb(kiocb))
835 		bio->bi_opf |= REQ_NOWAIT;
836 }
837 
838 #endif /* CONFIG_BLOCK */
839 #endif /* __LINUX_BIO_H */
840