1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
8 #include <linux/highmem.h>
9 #include <linux/mempool.h>
10 #include <linux/ioprio.h>
13 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
14 #include <linux/blk_types.h>
19 #define BIO_BUG_ON BUG_ON
24 #define BIO_MAX_PAGES 256
26 #define bio_prio(bio) (bio)->bi_ioprio
27 #define bio_set_prio(bio, prio) ((bio)->bi_ioprio = prio)
29 #define bio_iter_iovec(bio, iter) \
30 bvec_iter_bvec((bio)->bi_io_vec, (iter))
32 #define bio_iter_page(bio, iter) \
33 bvec_iter_page((bio)->bi_io_vec, (iter))
34 #define bio_iter_len(bio, iter) \
35 bvec_iter_len((bio)->bi_io_vec, (iter))
36 #define bio_iter_offset(bio, iter) \
37 bvec_iter_offset((bio)->bi_io_vec, (iter))
39 #define bio_page(bio) bio_iter_page((bio), (bio)->bi_iter)
40 #define bio_offset(bio) bio_iter_offset((bio), (bio)->bi_iter)
41 #define bio_iovec(bio) bio_iter_iovec((bio), (bio)->bi_iter)
43 #define bio_multiple_segments(bio) \
44 ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
46 #define bvec_iter_sectors(iter) ((iter).bi_size >> 9)
47 #define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
49 #define bio_sectors(bio) bvec_iter_sectors((bio)->bi_iter)
50 #define bio_end_sector(bio) bvec_iter_end_sector((bio)->bi_iter)
53 * Return the data direction, READ or WRITE.
55 #define bio_data_dir(bio) \
56 (op_is_write(bio_op(bio)) ? WRITE : READ)
59 * Check whether this bio carries any data or not. A NULL bio is allowed.
61 static inline bool bio_has_data(struct bio
*bio
)
64 bio
->bi_iter
.bi_size
&&
65 bio_op(bio
) != REQ_OP_DISCARD
&&
66 bio_op(bio
) != REQ_OP_SECURE_ERASE
&&
67 bio_op(bio
) != REQ_OP_WRITE_ZEROES
)
73 static inline bool bio_no_advance_iter(struct bio
*bio
)
75 return bio_op(bio
) == REQ_OP_DISCARD
||
76 bio_op(bio
) == REQ_OP_SECURE_ERASE
||
77 bio_op(bio
) == REQ_OP_WRITE_SAME
||
78 bio_op(bio
) == REQ_OP_WRITE_ZEROES
;
81 static inline bool bio_mergeable(struct bio
*bio
)
83 if (bio
->bi_opf
& REQ_NOMERGE_FLAGS
)
89 static inline unsigned int bio_cur_bytes(struct bio
*bio
)
91 if (bio_has_data(bio
))
92 return bio_iovec(bio
).bv_len
;
93 else /* dataless requests such as discard */
94 return bio
->bi_iter
.bi_size
;
97 static inline void *bio_data(struct bio
*bio
)
99 if (bio_has_data(bio
))
100 return page_address(bio_page(bio
)) + bio_offset(bio
);
105 static inline bool bio_full(struct bio
*bio
)
107 return bio
->bi_vcnt
>= bio
->bi_max_vecs
;
110 static inline bool bio_next_segment(const struct bio
*bio
,
111 struct bvec_iter_all
*iter
)
113 if (iter
->idx
>= bio
->bi_vcnt
)
116 bvec_advance(&bio
->bi_io_vec
[iter
->idx
], iter
);
121 * drivers should _never_ use the all version - the bio may have been split
122 * before it got to the driver and the driver won't own all of it
124 #define bio_for_each_segment_all(bvl, bio, iter) \
125 for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
127 static inline void bio_advance_iter(struct bio
*bio
, struct bvec_iter
*iter
,
130 iter
->bi_sector
+= bytes
>> 9;
132 if (bio_no_advance_iter(bio
))
133 iter
->bi_size
-= bytes
;
135 bvec_iter_advance(bio
->bi_io_vec
, iter
, bytes
);
136 /* TODO: It is reasonable to complete bio with error here. */
139 #define __bio_for_each_segment(bvl, bio, iter, start) \
140 for (iter = (start); \
142 ((bvl = bio_iter_iovec((bio), (iter))), 1); \
143 bio_advance_iter((bio), &(iter), (bvl).bv_len))
145 #define bio_for_each_segment(bvl, bio, iter) \
146 __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
148 #define __bio_for_each_bvec(bvl, bio, iter, start) \
149 for (iter = (start); \
151 ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
152 bio_advance_iter((bio), &(iter), (bvl).bv_len))
154 /* iterate over multi-page bvec */
155 #define bio_for_each_bvec(bvl, bio, iter) \
156 __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
158 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
160 static inline unsigned bio_segments(struct bio
*bio
)
164 struct bvec_iter iter
;
167 * We special case discard/write same/write zeroes, because they
168 * interpret bi_size differently:
171 switch (bio_op(bio
)) {
173 case REQ_OP_SECURE_ERASE
:
174 case REQ_OP_WRITE_ZEROES
:
176 case REQ_OP_WRITE_SAME
:
182 bio_for_each_segment(bv
, bio
, iter
)
189 * get a reference to a bio, so it won't disappear. the intended use is
193 * submit_bio(rw, bio);
194 * if (bio->bi_flags ...)
198 * without the bio_get(), it could potentially complete I/O before submit_bio
199 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
202 static inline void bio_get(struct bio
*bio
)
204 bio
->bi_flags
|= (1 << BIO_REFFED
);
205 smp_mb__before_atomic();
206 atomic_inc(&bio
->__bi_cnt
);
209 static inline void bio_cnt_set(struct bio
*bio
, unsigned int count
)
212 bio
->bi_flags
|= (1 << BIO_REFFED
);
213 smp_mb__before_atomic();
215 atomic_set(&bio
->__bi_cnt
, count
);
218 static inline bool bio_flagged(struct bio
*bio
, unsigned int bit
)
220 return (bio
->bi_flags
& (1U << bit
)) != 0;
223 static inline void bio_set_flag(struct bio
*bio
, unsigned int bit
)
225 bio
->bi_flags
|= (1U << bit
);
228 static inline void bio_clear_flag(struct bio
*bio
, unsigned int bit
)
230 bio
->bi_flags
&= ~(1U << bit
);
233 static inline void bio_get_first_bvec(struct bio
*bio
, struct bio_vec
*bv
)
235 *bv
= bio_iovec(bio
);
238 static inline void bio_get_last_bvec(struct bio
*bio
, struct bio_vec
*bv
)
240 struct bvec_iter iter
= bio
->bi_iter
;
243 if (unlikely(!bio_multiple_segments(bio
))) {
244 *bv
= bio_iovec(bio
);
248 bio_advance_iter(bio
, &iter
, iter
.bi_size
);
250 if (!iter
.bi_bvec_done
)
251 idx
= iter
.bi_idx
- 1;
252 else /* in the middle of bvec */
255 *bv
= bio
->bi_io_vec
[idx
];
258 * iter.bi_bvec_done records actual length of the last bvec
259 * if this bio ends in the middle of one io vector
261 if (iter
.bi_bvec_done
)
262 bv
->bv_len
= iter
.bi_bvec_done
;
265 static inline struct bio_vec
*bio_first_bvec_all(struct bio
*bio
)
267 WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
));
268 return bio
->bi_io_vec
;
271 static inline struct page
*bio_first_page_all(struct bio
*bio
)
273 return bio_first_bvec_all(bio
)->bv_page
;
276 static inline struct bio_vec
*bio_last_bvec_all(struct bio
*bio
)
278 WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
));
279 return &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
283 BIP_BLOCK_INTEGRITY
= 1 << 0, /* block layer owns integrity data */
284 BIP_MAPPED_INTEGRITY
= 1 << 1, /* ref tag has been remapped */
285 BIP_CTRL_NOCHECK
= 1 << 2, /* disable HBA integrity checking */
286 BIP_DISK_NOCHECK
= 1 << 3, /* disable disk integrity checking */
287 BIP_IP_CHECKSUM
= 1 << 4, /* IP checksum */
291 * bio integrity payload
293 struct bio_integrity_payload
{
294 struct bio
*bip_bio
; /* parent bio */
296 struct bvec_iter bip_iter
;
298 unsigned short bip_slab
; /* slab the bip came from */
299 unsigned short bip_vcnt
; /* # of integrity bio_vecs */
300 unsigned short bip_max_vcnt
; /* integrity bio_vec slots */
301 unsigned short bip_flags
; /* control flags */
303 struct bvec_iter bio_iter
; /* for rewinding parent bio */
305 struct work_struct bip_work
; /* I/O completion */
307 struct bio_vec
*bip_vec
;
308 struct bio_vec bip_inline_vecs
[0];/* embedded bvec array */
311 #if defined(CONFIG_BLK_DEV_INTEGRITY)
313 static inline struct bio_integrity_payload
*bio_integrity(struct bio
*bio
)
315 if (bio
->bi_opf
& REQ_INTEGRITY
)
316 return bio
->bi_integrity
;
321 static inline bool bio_integrity_flagged(struct bio
*bio
, enum bip_flags flag
)
323 struct bio_integrity_payload
*bip
= bio_integrity(bio
);
326 return bip
->bip_flags
& flag
;
331 static inline sector_t
bip_get_seed(struct bio_integrity_payload
*bip
)
333 return bip
->bip_iter
.bi_sector
;
336 static inline void bip_set_seed(struct bio_integrity_payload
*bip
,
339 bip
->bip_iter
.bi_sector
= seed
;
342 #endif /* CONFIG_BLK_DEV_INTEGRITY */
344 extern void bio_trim(struct bio
*bio
, int offset
, int size
);
345 extern struct bio
*bio_split(struct bio
*bio
, int sectors
,
346 gfp_t gfp
, struct bio_set
*bs
);
349 * bio_next_split - get next @sectors from a bio, splitting if necessary
351 * @sectors: number of sectors to split from the front of @bio
353 * @bs: bio set to allocate from
355 * Returns a bio representing the next @sectors of @bio - if the bio is smaller
356 * than @sectors, returns the original bio unchanged.
358 static inline struct bio
*bio_next_split(struct bio
*bio
, int sectors
,
359 gfp_t gfp
, struct bio_set
*bs
)
361 if (sectors
>= bio_sectors(bio
))
364 return bio_split(bio
, sectors
, gfp
, bs
);
368 BIOSET_NEED_BVECS
= BIT(0),
369 BIOSET_NEED_RESCUER
= BIT(1),
371 extern int bioset_init(struct bio_set
*, unsigned int, unsigned int, int flags
);
372 extern void bioset_exit(struct bio_set
*);
373 extern int biovec_init_pool(mempool_t
*pool
, int pool_entries
);
374 extern int bioset_init_from_src(struct bio_set
*bs
, struct bio_set
*src
);
376 extern struct bio
*bio_alloc_bioset(gfp_t
, unsigned int, struct bio_set
*);
377 extern void bio_put(struct bio
*);
379 extern void __bio_clone_fast(struct bio
*, struct bio
*);
380 extern struct bio
*bio_clone_fast(struct bio
*, gfp_t
, struct bio_set
*);
382 extern struct bio_set fs_bio_set
;
384 static inline struct bio
*bio_alloc(gfp_t gfp_mask
, unsigned int nr_iovecs
)
386 return bio_alloc_bioset(gfp_mask
, nr_iovecs
, &fs_bio_set
);
389 static inline struct bio
*bio_kmalloc(gfp_t gfp_mask
, unsigned int nr_iovecs
)
391 return bio_alloc_bioset(gfp_mask
, nr_iovecs
, NULL
);
394 extern blk_qc_t
submit_bio(struct bio
*);
396 extern void bio_endio(struct bio
*);
398 static inline void bio_io_error(struct bio
*bio
)
400 bio
->bi_status
= BLK_STS_IOERR
;
404 static inline void bio_wouldblock_error(struct bio
*bio
)
406 bio
->bi_status
= BLK_STS_AGAIN
;
410 struct request_queue
;
411 extern int bio_phys_segments(struct request_queue
*, struct bio
*);
413 extern int submit_bio_wait(struct bio
*bio
);
414 extern void bio_advance(struct bio
*, unsigned);
416 extern void bio_init(struct bio
*bio
, struct bio_vec
*table
,
417 unsigned short max_vecs
);
418 extern void bio_uninit(struct bio
*);
419 extern void bio_reset(struct bio
*);
420 void bio_chain(struct bio
*, struct bio
*);
422 extern int bio_add_page(struct bio
*, struct page
*, unsigned int,unsigned int);
423 extern int bio_add_pc_page(struct request_queue
*, struct bio
*, struct page
*,
424 unsigned int, unsigned int);
425 bool __bio_try_merge_page(struct bio
*bio
, struct page
*page
,
426 unsigned int len
, unsigned int off
, bool same_page
);
427 void __bio_add_page(struct bio
*bio
, struct page
*page
,
428 unsigned int len
, unsigned int off
);
429 int bio_iov_iter_get_pages(struct bio
*bio
, struct iov_iter
*iter
);
431 extern struct bio
*bio_map_user_iov(struct request_queue
*,
432 struct iov_iter
*, gfp_t
);
433 extern void bio_unmap_user(struct bio
*);
434 extern struct bio
*bio_map_kern(struct request_queue
*, void *, unsigned int,
436 extern struct bio
*bio_copy_kern(struct request_queue
*, void *, unsigned int,
438 extern void bio_set_pages_dirty(struct bio
*bio
);
439 extern void bio_check_pages_dirty(struct bio
*bio
);
441 void generic_start_io_acct(struct request_queue
*q
, int op
,
442 unsigned long sectors
, struct hd_struct
*part
);
443 void generic_end_io_acct(struct request_queue
*q
, int op
,
444 struct hd_struct
*part
,
445 unsigned long start_time
);
447 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
448 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
450 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
451 extern void bio_flush_dcache_pages(struct bio
*bi
);
453 static inline void bio_flush_dcache_pages(struct bio
*bi
)
458 extern void bio_copy_data_iter(struct bio
*dst
, struct bvec_iter
*dst_iter
,
459 struct bio
*src
, struct bvec_iter
*src_iter
);
460 extern void bio_copy_data(struct bio
*dst
, struct bio
*src
);
461 extern void bio_list_copy_data(struct bio
*dst
, struct bio
*src
);
462 extern void bio_free_pages(struct bio
*bio
);
464 extern struct bio
*bio_copy_user_iov(struct request_queue
*,
465 struct rq_map_data
*,
468 extern int bio_uncopy_user(struct bio
*);
469 void zero_fill_bio_iter(struct bio
*bio
, struct bvec_iter iter
);
471 static inline void zero_fill_bio(struct bio
*bio
)
473 zero_fill_bio_iter(bio
, bio
->bi_iter
);
476 extern struct bio_vec
*bvec_alloc(gfp_t
, int, unsigned long *, mempool_t
*);
477 extern void bvec_free(mempool_t
*, struct bio_vec
*, unsigned int);
478 extern unsigned int bvec_nr_vecs(unsigned short idx
);
479 extern const char *bio_devname(struct bio
*bio
, char *buffer
);
481 #define bio_set_dev(bio, bdev) \
483 if ((bio)->bi_disk != (bdev)->bd_disk) \
484 bio_clear_flag(bio, BIO_THROTTLED);\
485 (bio)->bi_disk = (bdev)->bd_disk; \
486 (bio)->bi_partno = (bdev)->bd_partno; \
487 bio_associate_blkg(bio); \
490 #define bio_copy_dev(dst, src) \
492 (dst)->bi_disk = (src)->bi_disk; \
493 (dst)->bi_partno = (src)->bi_partno; \
494 bio_clone_blkg_association(dst, src); \
497 #define bio_dev(bio) \
498 disk_devt((bio)->bi_disk)
500 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
501 void bio_associate_blkg_from_page(struct bio
*bio
, struct page
*page
);
503 static inline void bio_associate_blkg_from_page(struct bio
*bio
,
504 struct page
*page
) { }
507 #ifdef CONFIG_BLK_CGROUP
508 void bio_disassociate_blkg(struct bio
*bio
);
509 void bio_associate_blkg(struct bio
*bio
);
510 void bio_associate_blkg_from_css(struct bio
*bio
,
511 struct cgroup_subsys_state
*css
);
512 void bio_clone_blkg_association(struct bio
*dst
, struct bio
*src
);
513 #else /* CONFIG_BLK_CGROUP */
514 static inline void bio_disassociate_blkg(struct bio
*bio
) { }
515 static inline void bio_associate_blkg(struct bio
*bio
) { }
516 static inline void bio_associate_blkg_from_css(struct bio
*bio
,
517 struct cgroup_subsys_state
*css
)
519 static inline void bio_clone_blkg_association(struct bio
*dst
,
521 #endif /* CONFIG_BLK_CGROUP */
523 #ifdef CONFIG_HIGHMEM
525 * remember never ever reenable interrupts between a bvec_kmap_irq and
528 static inline char *bvec_kmap_irq(struct bio_vec
*bvec
, unsigned long *flags
)
533 * might not be a highmem page, but the preempt/irq count
534 * balancing is a lot nicer this way
536 local_irq_save(*flags
);
537 addr
= (unsigned long) kmap_atomic(bvec
->bv_page
);
539 BUG_ON(addr
& ~PAGE_MASK
);
541 return (char *) addr
+ bvec
->bv_offset
;
544 static inline void bvec_kunmap_irq(char *buffer
, unsigned long *flags
)
546 unsigned long ptr
= (unsigned long) buffer
& PAGE_MASK
;
548 kunmap_atomic((void *) ptr
);
549 local_irq_restore(*flags
);
553 static inline char *bvec_kmap_irq(struct bio_vec
*bvec
, unsigned long *flags
)
555 return page_address(bvec
->bv_page
) + bvec
->bv_offset
;
558 static inline void bvec_kunmap_irq(char *buffer
, unsigned long *flags
)
565 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
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.
576 static inline int bio_list_empty(const struct bio_list
*bl
)
578 return bl
->head
== NULL
;
581 static inline void bio_list_init(struct bio_list
*bl
)
583 bl
->head
= bl
->tail
= NULL
;
586 #define BIO_EMPTY_LIST { NULL, NULL }
588 #define bio_list_for_each(bio, bl) \
589 for (bio = (bl)->head; bio; bio = bio->bi_next)
591 static inline unsigned bio_list_size(const struct bio_list
*bl
)
596 bio_list_for_each(bio
, bl
)
602 static inline void bio_list_add(struct bio_list
*bl
, struct bio
*bio
)
607 bl
->tail
->bi_next
= bio
;
614 static inline void bio_list_add_head(struct bio_list
*bl
, struct bio
*bio
)
616 bio
->bi_next
= bl
->head
;
624 static inline void bio_list_merge(struct bio_list
*bl
, struct bio_list
*bl2
)
630 bl
->tail
->bi_next
= bl2
->head
;
632 bl
->head
= bl2
->head
;
634 bl
->tail
= bl2
->tail
;
637 static inline void bio_list_merge_head(struct bio_list
*bl
,
638 struct bio_list
*bl2
)
644 bl2
->tail
->bi_next
= bl
->head
;
646 bl
->tail
= bl2
->tail
;
648 bl
->head
= bl2
->head
;
651 static inline struct bio
*bio_list_peek(struct bio_list
*bl
)
656 static inline struct bio
*bio_list_pop(struct bio_list
*bl
)
658 struct bio
*bio
= bl
->head
;
661 bl
->head
= bl
->head
->bi_next
;
671 static inline struct bio
*bio_list_get(struct bio_list
*bl
)
673 struct bio
*bio
= bl
->head
;
675 bl
->head
= bl
->tail
= NULL
;
681 * Increment chain count for the bio. Make sure the CHAIN flag update
682 * is visible before the raised count.
684 static inline void bio_inc_remaining(struct bio
*bio
)
686 bio_set_flag(bio
, BIO_CHAIN
);
687 smp_mb__before_atomic();
688 atomic_inc(&bio
->__bi_remaining
);
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[].
697 #define BIO_POOL_SIZE 2
700 struct kmem_cache
*bio_slab
;
701 unsigned int front_pad
;
705 #if defined(CONFIG_BLK_DEV_INTEGRITY)
706 mempool_t bio_integrity_pool
;
707 mempool_t bvec_integrity_pool
;
711 * Deadlock avoidance for stacking block drivers: see comments in
712 * bio_alloc_bioset() for details
714 spinlock_t rescue_lock
;
715 struct bio_list rescue_list
;
716 struct work_struct rescue_work
;
717 struct workqueue_struct
*rescue_workqueue
;
723 struct kmem_cache
*slab
;
726 static inline bool bioset_initialized(struct bio_set
*bs
)
728 return bs
->bio_slab
!= NULL
;
732 * a small number of entries is fine, not going to be performance critical.
733 * basically we just need to survive
735 #define BIO_SPLIT_ENTRIES 2
737 #if defined(CONFIG_BLK_DEV_INTEGRITY)
739 #define bip_for_each_vec(bvl, bip, iter) \
740 for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
742 #define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
744 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
746 extern struct bio_integrity_payload
*bio_integrity_alloc(struct bio
*, gfp_t
, unsigned int);
747 extern int bio_integrity_add_page(struct bio
*, struct page
*, unsigned int, unsigned int);
748 extern bool bio_integrity_prep(struct bio
*);
749 extern void bio_integrity_advance(struct bio
*, unsigned int);
750 extern void bio_integrity_trim(struct bio
*);
751 extern int bio_integrity_clone(struct bio
*, struct bio
*, gfp_t
);
752 extern int bioset_integrity_create(struct bio_set
*, int);
753 extern void bioset_integrity_free(struct bio_set
*);
754 extern void bio_integrity_init(void);
756 #else /* CONFIG_BLK_DEV_INTEGRITY */
758 static inline void *bio_integrity(struct bio
*bio
)
763 static inline int bioset_integrity_create(struct bio_set
*bs
, int pool_size
)
768 static inline void bioset_integrity_free (struct bio_set
*bs
)
773 static inline bool bio_integrity_prep(struct bio
*bio
)
778 static inline int bio_integrity_clone(struct bio
*bio
, struct bio
*bio_src
,
784 static inline void bio_integrity_advance(struct bio
*bio
,
785 unsigned int bytes_done
)
790 static inline void bio_integrity_trim(struct bio
*bio
)
795 static inline void bio_integrity_init(void)
800 static inline bool bio_integrity_flagged(struct bio
*bio
, enum bip_flags flag
)
805 static inline void *bio_integrity_alloc(struct bio
* bio
, gfp_t gfp
,
808 return ERR_PTR(-EINVAL
);
811 static inline int bio_integrity_add_page(struct bio
*bio
, struct page
*page
,
812 unsigned int len
, unsigned int offset
)
817 #endif /* CONFIG_BLK_DEV_INTEGRITY */
820 * Mark a bio as polled. Note that for async polled IO, the caller must
821 * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
822 * We cannot block waiting for requests on polled IO, as those completions
823 * must be found by the caller. This is different than IRQ driven IO, where
824 * it's safe to wait for IO to complete.
826 static inline void bio_set_polled(struct bio
*bio
, struct kiocb
*kiocb
)
828 bio
->bi_opf
|= REQ_HIPRI
;
829 if (!is_sync_kiocb(kiocb
))
830 bio
->bi_opf
|= REQ_NOWAIT
;
833 #endif /* CONFIG_BLOCK */
834 #endif /* __LINUX_BIO_H */