[PATCH] mm: return -ENOMEM for page-table allocation failure in insert_pages()

[Avi Weiss <thnkslprpt@gmail.com>]

walk_to_pmd() returns NULL only when p4d_alloc(), pud_alloc(), or
pmd_alloc() fails. These are page-table allocation failures, but
insert_pages() currently reports them as -EFAULT.

Return -ENOMEM instead, consistent with the subsequent pte_alloc()
failure and with the single-page insert_page() path, which reports
failure of the same page-table allocation chain as -ENOMEM.

Address and range validation failures in vm_insert_pages() continue to
return -EFAULT. Keep the later -EFAULT return for
pte_offset_map_lock(), which is not an allocation failure.

Fixes: 8cd3984d81d5 ("mm/memory.c: add vm_insert_pages()")
Signed-off-by: Avi Weiss <thnkslprpt@gmail.com>
---
 mm/memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index ff338c2abe92..d8eddca8e251 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2436,7 +2436,7 @@ static int insert_pages(struct vm_area_struct *vma, unsigned long addr,
 	unsigned long pages_to_write_in_pmd;
 	int ret;
 more:
-	ret = -EFAULT;
+	ret = -ENOMEM;
 	pmd = walk_to_pmd(mm, addr);
 	if (!pmd)
 		goto out;
-- 
2.43.0