On Mon, Dec 09, 2019 at 08:11:14PM +0100, Andreas Gruenbacher wrote:
This partially reverts commit e3a5d8e386c3fb973fa75f2403622a8f3640ec06.
Commit e3a5d8e386c3 ("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: e3a5d8e386c3 ("block: check bi_size overflow before merge") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Andreas Gruenbacher agruenba@redhat.com
block/bio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/block/bio.c b/block/bio.c index 9d54aa37ce6c..a5d75f6bf4c7 100644 --- a/block/bio.c +++ b/block/bio.c @@ -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;
page merging doesn't consume new bvec, so this patch is correct:
Reviewed-by: Ming Lei ming.lei@redhat.com
Thanks, Ming