Fixes a regression introduced with commit 179ef71cbc085252
"mm: save soft-dirty bits on swapped pages"
The maybe_same_pte() function is used to match a swap pte independent
of the swap software dirty bit set with pte_swp_mksoft_dirty().
For CONFIG_HAVE_ARCH_SOFT_DIRTY=y but CONFIG_MEM_SOFT_DIRTY=n the
software dirty bit may be set but maybe_same_pte() will not recognize
a software dirty swap pte. Due to this a 'swapoff -a' will hang.
The straightforward solution is to replace CONFIG_MEM_SOFT_DIRTY
with HAVE_ARCH_SOFT_DIRTY in maybe_same_pte().
Cc: linux-mm@xxxxxxxxx
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
mm/swapfile.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 5887731..bf7da58 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1113,7 +1113,7 @@ unsigned int count_swap_pages(int type, int free)
static inline int maybe_same_pte(pte_t pte, pte_t swp_pte)
{
-#ifdef CONFIG_MEM_SOFT_DIRTY
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
/*
* When pte keeps soft dirty bit the pte generated
* from swap entry does not has it, still it's same
--
1.9.1
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