block: Fix page refcounts for unaligned buffers in __bio_release_pages()

commit 38b43539d64b2fa020b3b9a752a986769f87f7a6 upstream.

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>
[ Tony: backport to v6.1 by replacing bio_release_page() loop with
  folio_put_refs() as commits fd363244e883 and e4cc64657bec are not
  present. ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/block/bio.c b/block/bio.c
index 74c2818c7ec99dcb7fda12060ef870c1180e81bb..3318e0022fdfd19584f12b5c2b18c14ce7d99c4f 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1112,19 +1112,16 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty)
        struct folio_iter fi;
 
        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);
                        folio_mark_dirty(fi.folio);
                        folio_unlock(fi.folio);
                }
-               page = folio_page(fi.folio, fi.offset / PAGE_SIZE);
-               do {
-                       folio_put(fi.folio);
-                       done += PAGE_SIZE;
-               } while (done < fi.length);
+               nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE -
+                          fi.offset / PAGE_SIZE + 1;
+               folio_put_refs(fi.folio, nr_pages);
        }
 }
 EXPORT_SYMBOL_GPL(__bio_release_pages);