When the bio's size reaches max_append_sectors, bio_add_hw_page returns 0 then __bio_iov_append_get_pages returns -EINVAL. This is an expected result of building a small enough bio not to be split in the IO path. However, iov_iter is not advanced in this case, causing the same pages are filled for the bio again and again.

Fix the case by properly advancing the iov_iter for already processed pages.

Fixes: 0512a75b98f8 ("block: Introduce REQ_OP_ZONE_APPEND") Cc: stable@vger.kernel.org # 5.8+ Signed-off-by: Naohiro Aota naohiro.aota@wdc.com --- block/bio.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/block/bio.c b/block/bio.c index e0d41ccc4e90..2dfe40be4d6b 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1082,6 +1082,7 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter) ssize_t size, left; unsigned len, i; size_t offset; + int ret = 0;

if (WARN_ON_ONCE(!max_append_sectors)) return 0; @@ -1104,15 +1105,17 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)

len = min_t(size_t, PAGE_SIZE - offset, left); if (bio_add_hw_page(q, bio, page, len, offset, - max_append_sectors, &same_page) != len) - return -EINVAL; + max_append_sectors, &same_page) != len) { + ret = -EINVAL; + break; + } if (same_page) put_page(page); offset = 0; }

- iov_iter_advance(iter, size); - return 0; + iov_iter_advance(iter, size - left); + return ret; }

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