Commit 4977d121 authored Oct 28, 2020 by Naohiro Aota Committed by Jens Axboe Oct 28, 2020

block: advance iov_iter on bio_add_hw_page failure



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: 0512a75b ("block: Introduce REQ_OP_ZONE_APPEND")
Cc: stable@vger.kernel.org # 5.8+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 35bc10b2

block/bio.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -1044,6 +1044,7 @@ 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;
		@@ -1066,15 +1067,17 @@ 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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