[PATCH 6.6 098/396] block: Fix page refcounts for unaligned buffers in __bio_release_pages()

Greg Kroah-Hartman
2024-04-01T16:40:01Z

From: Tony Battersby <tonyb@cybernetics.com>

[ Upstream commit 38b43539d64b2fa020b3b9a752a986769f87f7a6 ]

Fix an incorrect number of pages being released for buffers that do not
start at the beginning of a page.

Fixes: 1b151e2435fc ("block: Remove special-casing of compound pages")
Cc: stable@vger.kernel.org
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Tested-by: Greg Edwards <gedwards@ddn.com>
Link: https://lore.kernel.org/r/86e592a9-98d4-4cff-a646-0c0084328356@cybernetics.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/bio.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 270f6b99926ea..62419aa09d731 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1149,7 +1149,7 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty)

bio_for_each_folio_all(fi, bio) {
struct page *page;
- size_t done = 0;
+ size_t nr_pages;

if (mark_dirty) {
folio_lock(fi.folio);
@@ -1157,10 +1157,11 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty)
folio_unlock(fi.folio);
}
page = folio_page(fi.folio, fi.offset / PAGE_SIZE);
+ nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE -
+ fi.offset / PAGE_SIZE + 1;
do {
bio_release_page(bio, page++);
- done += PAGE_SIZE;
- } while (done < fi.length);
+ } while (--nr_pages != 0);
}
}
EXPORT_SYMBOL_GPL(__bio_release_pages);
--
2.43.0