Commit 6dc4f100c175 ("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@xxxxxxx>
Cc: linux-btrfs@xxxxxxxxxxxxxxx
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Reported-and-Tested-by: Qu Wenruo <quwenruo.btrfs@xxxxxxx>
Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
include/linux/bio.h | 20 ++++++++++++--------
include/linux/bvec.h | 23 +++++++++++++++--------
2 files changed, 27 insertions(+), 16 deletions(-)
diff --git a/include/linux/bio.h b/include/linux/bio.h
index bb6090aa165d..9c583bf98ff9 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -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)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index f6275c4da13a..67eda310b643 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -47,8 +47,9 @@ struct bvec_iter {
struct bvec_iter_all {
struct bio_vec bv;
- int idx;
- unsigned done;
+ int idx; /* current index into bvec table */
+ unsigned bvec_done; /* number of bytes completed in
+ currnet bvec */
};
static inline struct page *bvec_nth_page(struct page *page, int idx)
@@ -145,18 +146,18 @@ 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->bvec_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->bvec_done) {
bv->bv_page = nth_page(bv->bv_page, 1);
bv->bv_offset = 0;
} else {
@@ -164,7 +165,13 @@ static inline void mp_bvec_next_segment(const struct bio_vec *bvec,
bv->bv_offset = bvec->bv_offset;
}
bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
- bvec->bv_len - iter_all->done);
+ bvec->bv_len - iter_all->bvec_done);
+ iter_all->bvec_done += bv->bv_len;
+
+ if (iter_all->bvec_done == bvec->bv_len) {
+ iter_all->idx++;
+ iter_all->bvec_done = 0;
+ }
}
/*
--
2.9.5
