[PATCH] mm/shmem/shmem_swapin_folio(): Fix uninitialized use of folio

[SeongJae Park]

Commit 2b58b3f33ba2 ("mm/shmem: convert shmem_swapin_page() to
shmem_swapin_folio()") in 'mm-unstable' tree introduces uninitialized
variable access as below when 'shmem_swapin_folio()' goes to 'failed'
path early.  This commit fixes it.

    linux/mm/shmem.c: In function ‘shmem_swapin_folio.isra.0’:
    linux/mm/shmem.c:1761:5: warning: ‘folio’ is used
    uninitialized in this function [-Wuninitialized]
     1761 |  if (folio) {
          |     ^

Fixes: 2b58b3f33ba2 ("mm/shmem: convert shmem_swapin_page() to shmem_swapin_folio()")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 820fde6c2ef6..6a18641a90ff 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1682,7 +1682,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
 	struct shmem_inode_info *info = SHMEM_I(inode);
 	struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL;
 	struct page *page;
-	struct folio *folio;
+	struct folio *folio = NULL;
 	swp_entry_t swap;
 	int error;
 
-- 
2.25.1