[PATCH] swapoff: use atomic_inc_not_zero() on mm_users
Now that we have atomic_inc_not_zero, it's more elegant for try_to_unuse to
use that on mm_users: doesn't actually matter at present, but safer to be
sure that once mm_users has gone to 0, nothing raises it for an instant.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index fbceed6..f2824c3c3 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -772,10 +772,8 @@
while (*swap_map > 1 && !retval &&
(p = p->next) != &start_mm->mmlist) {
mm = list_entry(p, struct mm_struct, mmlist);
- if (atomic_inc_return(&mm->mm_users) == 1) {
- atomic_dec(&mm->mm_users);
+ if (!atomic_inc_not_zero(&mm->mm_users))
continue;
- }
spin_unlock(&mmlist_lock);
mmput(prev_mm);
prev_mm = mm;
