[PATCH 04/22] shmem: move the shmem_mapping assert into shmem_get_folio_gfp

Christoph Hellwig
2024-02-19T06:27:44Z

Move the check that the inode really is a shmemfs one from
shmem_read_folio_gfp to shmem_get_folio_gfp given that shmem_get_folio
can also be called from outside of shmem.c. Also turn it into a
WARN_ON_ONCE and error return instead of BUG_ON to be less severe.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
mm/shmem.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 1900916aa84d13..ad533b2f0721a7 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1972,6 +1972,9 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
int error;
bool alloced;

+ if (WARN_ON_ONCE(!shmem_mapping(inode->i_mapping)))
+ return -EINVAL;
+
if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
return -EFBIG;
repeat:
@@ -4915,7 +4918,6 @@ struct folio *shmem_read_folio_gfp(struct address_space *mapping,
struct folio *folio;
int error;

- BUG_ON(!shmem_mapping(mapping));
error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE,
gfp, NULL, NULL);
if (error)
--
2.39.2