Commit 70af7c5c authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds

[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: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9637a5ef
...@@ -772,10 +772,8 @@ static int try_to_unuse(unsigned int type) ...@@ -772,10 +772,8 @@ static int try_to_unuse(unsigned int type)
while (*swap_map > 1 && !retval && while (*swap_map > 1 && !retval &&
(p = p->next) != &start_mm->mmlist) { (p = p->next) != &start_mm->mmlist) {
mm = list_entry(p, struct mm_struct, mmlist); mm = list_entry(p, struct mm_struct, mmlist);
if (atomic_inc_return(&mm->mm_users) == 1) { if (!atomic_inc_not_zero(&mm->mm_users))
atomic_dec(&mm->mm_users);
continue; continue;
}
spin_unlock(&mmlist_lock); spin_unlock(&mmlist_lock);
mmput(prev_mm); mmput(prev_mm);
prev_mm = mm; prev_mm = mm;
......
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