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block: fix "check bi_size overflow before merge" 

This partially reverts commit e3a5d8e386.

Commit e3a5d8e386 ("check bi_size overflow before merge") adds a bio_full
check to __bio_try_merge_page.  This will cause __bio_try_merge_page to fail
when the last bi_io_vec has been reached.  Instead, what we want here is only
the bi_size overflow check.

Fixes: e3a5d8e386 ("block: check bi_size overflow before merge")
Cc: stable@vger.kernel.org # v5.4+
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
alistair/sunxi64-5.5-dsi
Andreas Gruenbacher 2019-12-09 20:11:14 +01:00 committed by Jens Axboe
parent dc3ecfc981
commit cc90bc6842
1 changed files with 3 additions and 1 deletions
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block/bio.c
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@ -754,10 +754,12 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
return false;
if (bio->bi_vcnt > 0 && !bio_full(bio, len)) {
if (bio->bi_vcnt > 0) {
struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
if (page_is_mergeable(bv, page, len, off, same_page)) {
if (bio->bi_iter.bi_size > UINT_MAX - len)
return false;
bv->bv_len += len;
bio->bi_iter.bi_size += len;
return true;