[SRU][Noble][PATCH 2/3] mm/filemap: return early if failed to allocate memory for split

[Matthew Ruffell]

From: Kairui Song <kasong at tencent.com>

BugLink: https://bugs.launchpad.net/bugs/2085495

commit de60fd8ddeda2b41fbe11df11733838c5f684616 upstream.

xas_split_alloc could fail with NOMEM, and in such case, it should abort
early instead of keep going and fail the xas_split below.

Link: https://lkml.kernel.org/r/20240416071722.45997-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240415171857.19244-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240415171857.19244-2-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong at tencent.com>
Acked-by: Matthew Wilcox (Oracle) <willy at infradead.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Stable-dep-of: 6758c1128ceb ("mm/filemap: optimize filemap folio adding")
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit ff3c557fa93e7fcf5891e38fa7285b3c44e994b3 6.6.y)
Signed-off-by: Matthew Ruffell <matthew.ruffell at canonical.com>
Signed-off-by: Chengen Du <chengen.du at canonical.com>
---
 mm/filemap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 605a779e23ca..33ad16c126c0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -871,9 +871,12 @@ noinline int __filemap_add_folio(struct address_space *mapping,
 		unsigned int order = xa_get_order(xas.xa, xas.xa_index);
 		void *entry, *old = NULL;
 
-		if (order > folio_order(folio))
+		if (order > folio_order(folio)) {
 			xas_split_alloc(&xas, xa_load(xas.xa, xas.xa_index),
 					order, gfp);
+			if (xas_error(&xas))
+				goto error;
+		}
 		xas_lock_irq(&xas);
 		xas_for_each_conflict(&xas, entry) {
 			old = entry;
-- 
2.45.2