diff options
| author |   Ming Lei <ming.lei@redhat.com> | 2020-08-17 18:00:55 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2020-09-02 20:59:40 -0600 |
| commit | 7e24969022cbd61ddc586f14824fc205661bb124 (patch) | |
| tree | 64854a523b26e7ae9f058097b5d0e5bbacaf4bd7 | |
| parent | blk-stat: make q->stats->lock irqsafe (diff) | |
| download | wireguard-linux-7e24969022cbd61ddc586f14824fc205661bb124.tar.xz wireguard-linux-7e24969022cbd61ddc586f14824fc205661bb124.zip | |
block: allow for_each_bvec to support zero len bvec
Block layer usually doesn't support or allow zero-length bvec. Since
commit 1bdc76aea115 ("iov_iter: use bvec iterator to implement
iterate_bvec()"), iterate_bvec() switches to bvec iterator. However,
Al mentioned that 'Zero-length segments are not disallowed' in iov_iter.
Fixes for_each_bvec() so that it can move on after seeing one zero
length bvec.
Fixes: 1bdc76aea115 ("iov_iter: use bvec iterator to implement iterate_bvec()")
Reported-by: syzbot <syzbot+61acc40a49a3e46e25ea@syzkaller.appspotmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Link: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2262077.html
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | include/linux/bvec.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index ac0c7299d5b8..dd74503f7e5e 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -117,11 +117,18 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv, return true; } +static inline void bvec_iter_skip_zero_bvec(struct bvec_iter *iter) +{ + iter->bi_bvec_done = 0; + iter->bi_idx++; +} + #define for_each_bvec(bvl, bio_vec, iter, start) \ for (iter = (start); \ (iter).bi_size && \ ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \ - bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len)) + (bvl).bv_len ? (void)bvec_iter_advance((bio_vec), &(iter), \ + (bvl).bv_len) : bvec_iter_skip_zero_bvec(&(iter))) /* for iterating one bio from start to end */ #define BVEC_ITER_ALL_INIT (struct bvec_iter) \ |