[PATCH] block: Fix potential page reference leak in __bio_iov_append_get_pages()

[Miaohe Lin]

When bio_add_hw_page() failed, we left page reference still held in pages.
Release these references and advance the iov_iter according to what we
have done successfully yet.

Fixes: 0512a75b98f8 ("block: Introduce REQ_OP_ZONE_APPEND")
Signed-off-by: Miaohe Lin <linmia...@huawei.com>
---
 block/bio.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index e113073958cb..a323a5446221 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1080,7 +1080,7 @@ 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;
+                       goto put_pages;
                if (same_page)
                        put_page(page);
                offset = 0;
@@ -1088,6 +1088,16 @@ static int __bio_iov_append_get_pages(struct bio *bio, 
struct iov_iter *iter)
 
        iov_iter_advance(iter, size);
        return 0;
+put_pages:
+       iov_iter_advance(iter, size - left);
+       for (; left > 0; left -= len, i++) {
+               struct page *page = pages[i];
+
+               len = min_t(size_t, PAGE_SIZE - offset, left);
+               put_page(page);
+               offset = 0;
+       }
+       return -EINVAL;
 }
 
 /**
-- 
2.19.1