mm: Fix is_zero_page() usage in try_grab_page()

The backport of upstream commit c8070b787519 ("mm: Don't pin ZERO_PAGE
in pin_user_pages()") into v6.1.130 noted below in Fixes does not
account for commit 0f0892356fa1 ("mm: allow multiple error returns in
try_grab_page()"), which changed the return value of try_grab_page()
from bool to int.  Therefore returning 0, success in the upstream
version, becomes an error here.  Fix the return value.

Fixes: 476c1dfefab8 ("mm: Don't pin ZERO_PAGE in pin_user_pages()")
Link: https://lore.kernel.org/all/Z_6uhLQjJ7SSzI13@eldamar.lan
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Reported-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: stable@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/gup.c b/mm/gup.c
index b4edb67087332086517327ac69dc221b376024ac..37c55e61460e2acadc67b7e803dfec07e2a88ee2 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -232,7 +232,7 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags)
                 * and it is used in a *lot* of places.
                 */
                if (is_zero_page(page))
-                       return 0;
+                       return true;
 
                /*
                 * Similar to try_grab_folio(): be sure to *also*