Viewing file:  bio.h (21.15 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2001 Jens Axboe <[email protected]>
*/
#ifndef __LINUX_BIO_H
#define __LINUX_BIO_H
#include <linux/mempool.h>
/* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
#include <linux/blk_types.h>
#include <linux/uio.h>
#define BIO_MAX_VECS 256U
struct queue_limits;
static inline unsigned int bio_max_segs(unsigned int nr_segs)
{
return min(nr_segs, BIO_MAX_VECS);
}
#define bio_prio(bio) (bio)->bi_ioprio
#define bio_set_prio(bio, prio) ((bio)->bi_ioprio = prio)
#define bio_iter_iovec(bio, iter) \
bvec_iter_bvec((bio)->bi_io_vec, (iter))
#define bio_iter_page(bio, iter) \
bvec_iter_page((bio)->bi_io_vec, (iter))
#define bio_iter_len(bio, iter) \
bvec_iter_len((bio)->bi_io_vec, (iter))
#define bio_iter_offset(bio, iter) \
bvec_iter_offset((bio)->bi_io_vec, (iter))
#define bio_page(bio) bio_iter_page((bio), (bio)->bi_iter)
#define bio_offset(bio) bio_iter_offset((bio), (bio)->bi_iter)
#define bio_iovec(bio) bio_iter_iovec((bio), (bio)->bi_iter)
#define bvec_iter_sectors(iter) ((iter).bi_size >> 9)
#define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
#define bio_sectors(bio) bvec_iter_sectors((bio)->bi_iter)
#define bio_end_sector(bio) bvec_iter_end_sector((bio)->bi_iter)
/*
* Return the data direction, READ or WRITE.
*/
#define bio_data_dir(bio) \
(op_is_write(bio_op(bio)) ? WRITE : READ)
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
static inline bool bio_has_data(struct bio *bio)
{
if (bio &&
bio->bi_iter.bi_size &&
bio_op(bio) != REQ_OP_DISCARD &&
bio_op(bio) != REQ_OP_SECURE_ERASE &&
bio_op(bio) != REQ_OP_WRITE_ZEROES)
return true;
return false;
}
static inline bool bio_no_advance_iter(const struct bio *bio)
{
return bio_op(bio) == REQ_OP_DISCARD ||
bio_op(bio) == REQ_OP_SECURE_ERASE ||
bio_op(bio) == REQ_OP_WRITE_ZEROES;
}
static inline void *bio_data(struct bio *bio)
{
if (bio_has_data(bio))
return page_address(bio_page(bio)) + bio_offset(bio);
return NULL;
}
static inline bool bio_next_segment(const struct bio *bio,
struct bvec_iter_all *iter)
{
if (iter->idx >= bio->bi_vcnt)
return false;
bvec_advance(&bio->bi_io_vec[iter->idx], iter);
return true;
}
/*
* drivers should _never_ use the all version - the bio may have been split
* before it got to the driver and the driver won't own all of it
*/
#define bio_for_each_segment_all(bvl, bio, iter) \
for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
static inline void bio_advance_iter(const struct bio *bio,
struct bvec_iter *iter, unsigned int bytes)
{
iter->bi_sector += bytes >> 9;
if (bio_no_advance_iter(bio))
iter->bi_size -= bytes;
else
bvec_iter_advance(bio->bi_io_vec, iter, bytes);
/* TODO: It is reasonable to complete bio with error here. */
}
/* @bytes should be less or equal to bvec[i->bi_idx].bv_len */
static inline void bio_advance_iter_single(const struct bio *bio,
struct bvec_iter *iter,
unsigned int bytes)
{
iter->bi_sector += bytes >> 9;
if (bio_no_advance_iter(bio))
iter->bi_size -= bytes;
else
bvec_iter_advance_single(bio->bi_io_vec, iter, bytes);
}
void __bio_advance(struct bio *, unsigned bytes);
/**
* bio_advance - increment/complete a bio by some number of bytes
* @bio: bio to advance
* @nbytes: number of bytes to complete
*
* This updates bi_sector, bi_size and bi_idx; if the number of bytes to
* complete doesn't align with a bvec boundary, then bv_len and bv_offset will
* be updated on the last bvec as well.
*
* @bio will then represent the remaining, uncompleted portion of the io.
*/
static inline void bio_advance(struct bio *bio, unsigned int nbytes)
{
if (nbytes == bio->bi_iter.bi_size) {
bio->bi_iter.bi_size = 0;
return;
}
__bio_advance(bio, nbytes);
}
#define __bio_for_each_segment(bvl, bio, iter, start) \
for (iter = (start); \
(iter).bi_size && \
((bvl = bio_iter_iovec((bio), (iter))), 1); \
bio_advance_iter_single((bio), &(iter), (bvl).bv_len))
#define bio_for_each_segment(bvl, bio, iter) \
__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
#define __bio_for_each_bvec(bvl, bio, iter, start) \
for (iter = (start); \
(iter).bi_size && \
((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
bio_advance_iter_single((bio), &(iter), (bvl).bv_len))
/* iterate over multi-page bvec */
#define bio_for_each_bvec(bvl, bio, iter) \
__bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
/*
* Iterate over all multi-page bvecs. Drivers shouldn't use this version for the
* same reasons as bio_for_each_segment_all().
*/
#define bio_for_each_bvec_all(bvl, bio, i) \
for (i = 0, bvl = bio_first_bvec_all(bio); \
i < (bio)->bi_vcnt; i++, bvl++)
#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
static inline unsigned bio_segments(struct bio *bio)
{
unsigned segs = 0;
struct bio_vec bv;
struct bvec_iter iter;
/*
* We special case discard/write same/write zeroes, because they
* interpret bi_size differently:
*/
switch (bio_op(bio)) {
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_ZEROES:
return 0;
default:
break;
}
bio_for_each_segment(bv, bio, iter)
segs++;
return segs;
}
/*
* get a reference to a bio, so it won't disappear. the intended use is
* something like:
*
* bio_get(bio);
* submit_bio(rw, bio);
* if (bio->bi_flags ...)
* do_something
* bio_put(bio);
*
* without the bio_get(), it could potentially complete I/O before submit_bio
* returns. and then bio would be freed memory when if (bio->bi_flags ...)
* runs
*/
static inline void bio_get(struct bio *bio)
{
bio->bi_flags |= (1 << BIO_REFFED);
smp_mb__before_atomic();
atomic_inc(&bio->__bi_cnt);
}
static inline void bio_cnt_set(struct bio *bio, unsigned int count)
{
if (count != 1) {
bio->bi_flags |= (1 << BIO_REFFED);
smp_mb();
}
atomic_set(&bio->__bi_cnt, count);
}
static inline bool bio_flagged(struct bio *bio, unsigned int bit)
{
return bio->bi_flags & (1U << bit);
}
static inline void bio_set_flag(struct bio *bio, unsigned int bit)
{
bio->bi_flags |= (1U << bit);
}
static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
{
bio->bi_flags &= ~(1U << bit);
}
static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
{
WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
return bio->bi_io_vec;
}
static inline struct page *bio_first_page_all(struct bio *bio)
{
return bio_first_bvec_all(bio)->bv_page;
}
static inline struct folio *bio_first_folio_all(struct bio *bio)
{
return page_folio(bio_first_page_all(bio));
}
static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
{
WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
return &bio->bi_io_vec[bio->bi_vcnt - 1];
}
/**
* struct folio_iter - State for iterating all folios in a bio.
* @folio: The current folio we're iterating. NULL after the last folio.
* @offset: The byte offset within the current folio.
* @length: The number of bytes in this iteration (will not cross folio
* boundary).
*/
struct folio_iter {
struct folio *folio;
size_t offset;
size_t length;
/* private: for use by the iterator */
struct folio *_next;
size_t _seg_count;
int _i;
};
static inline void bio_first_folio(struct folio_iter *fi, struct bio *bio,
int i)
{
struct bio_vec *bvec = bio_first_bvec_all(bio) + i;
if (unlikely(i >= bio->bi_vcnt)) {
fi->folio = NULL;
return;
}
fi->folio = page_folio(bvec->bv_page);
fi->offset = bvec->bv_offset +
PAGE_SIZE * (bvec->bv_page - &fi->folio->page);
fi->_seg_count = bvec->bv_len;
fi->length = min(folio_size(fi->folio) - fi->offset, fi->_seg_count);
fi->_next = folio_next(fi->folio);
fi->_i = i;
}
static inline void bio_next_folio(struct folio_iter *fi, struct bio *bio)
{
fi->_seg_count -= fi->length;
if (fi->_seg_count) {
fi->folio = fi->_next;
fi->offset = 0;
fi->length = min(folio_size(fi->folio), fi->_seg_count);
fi->_next = folio_next(fi->folio);
} else {
bio_first_folio(fi, bio, fi->_i + 1);
}
}
/**
* bio_for_each_folio_all - Iterate over each folio in a bio.
* @fi: struct folio_iter which is updated for each folio.
* @bio: struct bio to iterate over.
*/
#define bio_for_each_folio_all(fi, bio) \
for (bio_first_folio(&fi, bio, 0); fi.folio; bio_next_folio(&fi, bio))
enum bip_flags {
BIP_BLOCK_INTEGRITY = 1 << 0, /* block layer owns integrity data */
BIP_MAPPED_INTEGRITY = 1 << 1, /* ref tag has been remapped */
BIP_CTRL_NOCHECK = 1 << 2, /* disable HBA integrity checking */
BIP_DISK_NOCHECK = 1 << 3, /* disable disk integrity checking */
BIP_IP_CHECKSUM = 1 << 4, /* IP checksum */
BIP_INTEGRITY_USER = 1 << 5, /* Integrity payload is user address */
BIP_COPY_USER = 1 << 6, /* Kernel bounce buffer in use */
};
/*
* bio integrity payload
*/
struct bio_integrity_payload {
struct bio *bip_bio; /* parent bio */
struct bvec_iter bip_iter;
unsigned short bip_vcnt; /* # of integrity bio_vecs */
unsigned short bip_max_vcnt; /* integrity bio_vec slots */
unsigned short bip_flags; /* control flags */
struct bvec_iter bio_iter; /* for rewinding parent bio */
struct work_struct bip_work; /* I/O completion */
struct bio_vec *bip_vec;
struct bio_vec bip_inline_vecs[];/* embedded bvec array */
};
#if defined(CONFIG_BLK_DEV_INTEGRITY)
static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
{
if (bio->bi_opf & REQ_INTEGRITY)
return bio->bi_integrity;
return NULL;
}
static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
{
struct bio_integrity_payload *bip = bio_integrity(bio);
if (bip)
return bip->bip_flags & flag;
return false;
}
static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
{
return bip->bip_iter.bi_sector;
}
static inline void bip_set_seed(struct bio_integrity_payload *bip,
sector_t seed)
{
bip->bip_iter.bi_sector = seed;
}
#endif /* CONFIG_BLK_DEV_INTEGRITY */
void bio_trim(struct bio *bio, sector_t offset, sector_t size);
extern struct bio *bio_split(struct bio *bio, int sectors,
gfp_t gfp, struct bio_set *bs);
struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
unsigned *segs, struct bio_set *bs, unsigned max_bytes);
/**
* bio_next_split - get next @sectors from a bio, splitting if necessary
* @bio: bio to split
* @sectors: number of sectors to split from the front of @bio
* @gfp: gfp mask
* @bs: bio set to allocate from
*
* Return: a bio representing the next @sectors of @bio - if the bio is smaller
* than @sectors, returns the original bio unchanged.
*/
static inline struct bio *bio_next_split(struct bio *bio, int sectors,
gfp_t gfp, struct bio_set *bs)
{
if (sectors >= bio_sectors(bio))
return bio;
return bio_split(bio, sectors, gfp, bs);
}
enum {
BIOSET_NEED_BVECS = BIT(0),
BIOSET_NEED_RESCUER = BIT(1),
BIOSET_PERCPU_CACHE = BIT(2),
};
extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
extern void bioset_exit(struct bio_set *);
extern int biovec_init_pool(mempool_t *pool, int pool_entries);
struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,
blk_opf_t opf, gfp_t gfp_mask,
struct bio_set *bs);
struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask);
extern void bio_put(struct bio *);
struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src,
gfp_t gfp, struct bio_set *bs);
int bio_init_clone(struct block_device *bdev, struct bio *bio,
struct bio *bio_src, gfp_t gfp);
extern struct bio_set fs_bio_set;
static inline struct bio *bio_alloc(struct block_device *bdev,
unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp_mask)
{
return bio_alloc_bioset(bdev, nr_vecs, opf, gfp_mask, &fs_bio_set);
}
void submit_bio(struct bio *bio);
extern void bio_endio(struct bio *);
static inline void bio_io_error(struct bio *bio)
{
bio->bi_status = BLK_STS_IOERR;
bio_endio(bio);
}
static inline void bio_wouldblock_error(struct bio *bio)
{
bio_set_flag(bio, BIO_QUIET);
bio->bi_status = BLK_STS_AGAIN;
bio_endio(bio);
}
/*
* Calculate number of bvec segments that should be allocated to fit data
* pointed by @iter. If @iter is backed by bvec it's going to be reused
* instead of allocating a new one.
*/
static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs)
{
if (iov_iter_is_bvec(iter))
return 0;
return iov_iter_npages(iter, max_segs);
}
struct request_queue;
extern int submit_bio_wait(struct bio *bio);
void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table,
unsigned short max_vecs, blk_opf_t opf);
extern void bio_uninit(struct bio *);
void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf);
void bio_chain(struct bio *, struct bio *);
int __must_check bio_add_page(struct bio *bio, struct page *page, unsigned len,
unsigned off);
bool __must_check bio_add_folio(struct bio *bio, struct folio *folio,
size_t len, size_t off);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
unsigned int, unsigned int);
int bio_add_zone_append_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int offset);
void __bio_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int off);
void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len,
size_t off);
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter);
void __bio_release_pages(struct bio *bio, bool mark_dirty);
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);
extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
struct bio *src, struct bvec_iter *src_iter);
extern void bio_copy_data(struct bio *dst, struct bio *src);
extern void bio_free_pages(struct bio *bio);
void guard_bio_eod(struct bio *bio);
void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
static inline void zero_fill_bio(struct bio *bio)
{
zero_fill_bio_iter(bio, bio->bi_iter);
}
static inline void bio_release_pages(struct bio *bio, bool mark_dirty)
{
if (bio_flagged(bio, BIO_PAGE_PINNED))
__bio_release_pages(bio, mark_dirty);
}
#define bio_dev(bio) \
disk_devt((bio)->bi_bdev->bd_disk)
#ifdef CONFIG_BLK_CGROUP
void bio_associate_blkg(struct bio *bio);
void bio_associate_blkg_from_css(struct bio *bio,
struct cgroup_subsys_state *css);
void bio_clone_blkg_association(struct bio *dst, struct bio *src);
void blkcg_punt_bio_submit(struct bio *bio);
#else /* CONFIG_BLK_CGROUP */
static inline void bio_associate_blkg(struct bio *bio) { }
static inline void bio_associate_blkg_from_css(struct bio *bio,
struct cgroup_subsys_state *css)
{ }
static inline void bio_clone_blkg_association(struct bio *dst,
struct bio *src) { }
static inline void blkcg_punt_bio_submit(struct bio *bio)
{
submit_bio(bio);
}
#endif /* CONFIG_BLK_CGROUP */
static inline void bio_set_dev(struct bio *bio, struct block_device *bdev)
{
bio_clear_flag(bio, BIO_REMAPPED);
if (bio->bi_bdev != bdev)
bio_clear_flag(bio, BIO_BPS_THROTTLED);
bio->bi_bdev = bdev;
bio_associate_blkg(bio);
}
/*
* BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
*
* A bio_list anchors a singly-linked list of bios chained through the bi_next
* member of the bio. The bio_list also caches the last list member to allow
* fast access to the tail.
*/
struct bio_list {
struct bio *head;
struct bio *tail;
};
static inline int bio_list_empty(const struct bio_list *bl)
{
return bl->head == NULL;
}
static inline void bio_list_init(struct bio_list *bl)
{
bl->head = bl->tail = NULL;
}
#define BIO_EMPTY_LIST { NULL, NULL }
#define bio_list_for_each(bio, bl) \
for (bio = (bl)->head; bio; bio = bio->bi_next)
static inline unsigned bio_list_size(const struct bio_list *bl)
{
unsigned sz = 0;
struct bio *bio;
bio_list_for_each(bio, bl)
sz++;
return sz;
}
static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
{
bio->bi_next = NULL;
if (bl->tail)
bl->tail->bi_next = bio;
else
bl->head = bio;
bl->tail = bio;
}
static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
{
bio->bi_next = bl->head;
bl->head = bio;
if (!bl->tail)
bl->tail = bio;
}
static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
{
if (!bl2->head)
return;
if (bl->tail)
bl->tail->bi_next = bl2->head;
else
bl->head = bl2->head;
bl->tail = bl2->tail;
}
static inline void bio_list_merge_head(struct bio_list *bl,
struct bio_list *bl2)
{
if (!bl2->head)
return;
if (bl->head)
bl2->tail->bi_next = bl->head;
else
bl->tail = bl2->tail;
bl->head = bl2->head;
}
static inline struct bio *bio_list_peek(struct bio_list *bl)
{
return bl->head;
}
static inline struct bio *bio_list_pop(struct bio_list *bl)
{
struct bio *bio = bl->head;
if (bio) {
bl->head = bl->head->bi_next;
if (!bl->head)
bl->tail = NULL;
bio->bi_next = NULL;
}
return bio;
}
static inline struct bio *bio_list_get(struct bio_list *bl)
{
struct bio *bio = bl->head;
bl->head = bl->tail = NULL;
return bio;
}
/*
* Increment chain count for the bio. Make sure the CHAIN flag update
* is visible before the raised count.
*/
static inline void bio_inc_remaining(struct bio *bio)
{
bio_set_flag(bio, BIO_CHAIN);
smp_mb__before_atomic();
atomic_inc(&bio->__bi_remaining);
}
/*
* bio_set is used to allow other portions of the IO system to
* allocate their own private memory pools for bio and iovec structures.
* These memory pools in turn all allocate from the bio_slab
* and the bvec_slabs[].
*/
#define BIO_POOL_SIZE 2
struct bio_set {
struct kmem_cache *bio_slab;
unsigned int front_pad;
/*
* per-cpu bio alloc cache
*/
struct bio_alloc_cache __percpu *cache;
mempool_t bio_pool;
mempool_t bvec_pool;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
mempool_t bio_integrity_pool;
mempool_t bvec_integrity_pool;
#endif
unsigned int back_pad;
/*
* Deadlock avoidance for stacking block drivers: see comments in
* bio_alloc_bioset() for details
*/
spinlock_t rescue_lock;
struct bio_list rescue_list;
struct work_struct rescue_work;
struct workqueue_struct *rescue_workqueue;
/*
* Hot un-plug notifier for the per-cpu cache, if used
*/
struct hlist_node cpuhp_dead;
};
static inline bool bioset_initialized(struct bio_set *bs)
{
return bs->bio_slab != NULL;
}
#if defined(CONFIG_BLK_DEV_INTEGRITY)
#define bip_for_each_vec(bvl, bip, iter) \
for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
#define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
for_each_bio(_bio) \
bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t len, u32 seed);
extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
extern bool bio_integrity_prep(struct bio *);
extern void bio_integrity_advance(struct bio *, unsigned int);
extern void bio_integrity_trim(struct bio *);
extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
extern int bioset_integrity_create(struct bio_set *, int);
extern void bioset_integrity_free(struct bio_set *);
extern void bio_integrity_init(void);
#else /* CONFIG_BLK_DEV_INTEGRITY */
static inline void *bio_integrity(struct bio *bio)
{
return NULL;
}
static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
{
return 0;
}
static inline void bioset_integrity_free (struct bio_set *bs)
{
return;
}
static inline bool bio_integrity_prep(struct bio *bio)
{
return true;
}
static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
gfp_t gfp_mask)
{
return 0;
}
static inline void bio_integrity_advance(struct bio *bio,
unsigned int bytes_done)
{
return;
}
static inline void bio_integrity_trim(struct bio *bio)
{
return;
}
static inline void bio_integrity_init(void)
{
return;
}
static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
{
return false;
}
static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
unsigned int nr)
{
return ERR_PTR(-EINVAL);
}
static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
return 0;
}
static inline int bio_integrity_map_user(struct bio *bio, void __user *ubuf,
ssize_t len, u32 seed)
{
return -EINVAL;
}
#endif /* CONFIG_BLK_DEV_INTEGRITY */
/*
* Mark a bio as polled. Note that for async polled IO, the caller must
* expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
* We cannot block waiting for requests on polled IO, as those completions
* must be found by the caller. This is different than IRQ driven IO, where
* it's safe to wait for IO to complete.
*/
static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
{
bio->bi_opf |= REQ_POLLED;
if (kiocb->ki_flags & IOCB_NOWAIT)
bio->bi_opf |= REQ_NOWAIT;
}
static inline void bio_clear_polled(struct bio *bio)
{
bio->bi_opf &= ~REQ_POLLED;
}
struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
unsigned int nr_pages, blk_opf_t opf, gfp_t gfp);
#endif /* __LINUX_BIO_H */
|