From 4977d121bc9bc5138d4d48b85469123001859573 Mon Sep 17 00:00:00 2001
From: Naohiro Aota <naohiro.aota@wdc.com>
Date: Wed, 28 Oct 2020 16:25:36 +0900
Subject: [PATCH] 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: 0512a75b98f8 ("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>
---
block/bio.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index e6e26d7a1ffbb..fa01bef35bb1f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -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;
}
/**
--
2.30.2