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block: don't use for-inside-for in bio_for_each_segment_all

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Commit 6dc4f100c1 ("block: allow bio_for_each_segment_all() to
iterate over multi-page bvec") changes bio_for_each_segment_all()
to use for-inside-for.

This way breaks all bio_for_each_segment_all() call with error out
branch via 'break', since now 'break' can only break from the inner
loop.

Fixes this issue by implementing bio_for_each_segment_all() via
single 'for' loop, and now the logic is very similar with normal
bvec iterator.

Cc: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: linux-btrfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: Omar Sandoval <osandov@fb.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-and-Tested-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
Fixes: 6dc4f100c1 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2019-04-08 19:02:38 +08:00 • committed by Jens Axboe
parent 15ade5d2e7
commit 1200e07f3a
2 changed files with 22 additions and 12 deletions
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20
include/linux/bio.h
View file

@ -120,19 +120,23 @@ static inline bool bio_full(struct bio *bio)
return bio->bi_vcnt >= bio->bi_max_vecs;
}
#define mp_bvec_for_each_segment(bv, bvl, i, iter_all) \
for (bv = bvec_init_iter_all(&iter_all); \
(iter_all.done < (bvl)->bv_len) && \
(mp_bvec_next_segment((bvl), &iter_all), 1); \
iter_all.done += bv->bv_len, i += 1)
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, i, iter_all) \
for (i = 0, iter_all.idx = 0; iter_all.idx < (bio)->bi_vcnt; iter_all.idx++) \
mp_bvec_for_each_segment(bvl, &((bio)->bi_io_vec[iter_all.idx]), i, iter_all)
#define bio_for_each_segment_all(bvl, bio, i, iter) \
for (i = 0, bvl = bvec_init_iter_all(&iter); \
bio_next_segment((bio), &iter); i++)
static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
unsigned bytes)

14
include/linux/bvec.h
View file

@ -145,18 +145,18 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv,
static inline struct bio_vec *bvec_init_iter_all(struct bvec_iter_all *iter_all)
{
iter_all->bv.bv_page = NULL;
iter_all->done = 0;
iter_all->idx = 0;
return &iter_all->bv;
}
static inline void mp_bvec_next_segment(const struct bio_vec *bvec,
struct bvec_iter_all *iter_all)
static inline void bvec_advance(const struct bio_vec *bvec,
struct bvec_iter_all *iter_all)
{
struct bio_vec *bv = &iter_all->bv;
if (bv->bv_page) {
if (iter_all->done) {
bv->bv_page = nth_page(bv->bv_page, 1);
bv->bv_offset = 0;
} else {
@ -165,6 +165,12 @@ static inline void mp_bvec_next_segment(const struct bio_vec *bvec,
}
bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
bvec->bv_len - iter_all->done);
iter_all->done += bv->bv_len;
if (iter_all->done == bvec->bv_len) {
iter_all->idx++;
iter_all->done = 0;
}
}
/*