mm: swapfile: clean up unuse_pte race handling

The conditional mem_cgroup_cancel_charge_swapin() is a leftover from when
the function would continue to reestablish the page even after
mem_cgroup_try_charge_swapin() failed.  After 85d9fc8 "memcg: fix refcnt
handling at swapoff", the condition is always true when this code is
reached.

Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: KAMEZAWA Hiroyuki <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 63958d60ecb080728343c52f3728b4aebe93c5bd..14e254c768fc5090e9c2276085b3c6f96c6255f6 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -835,8 +835,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 
        pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
        if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) {
-               if (ret > 0)
-                       mem_cgroup_cancel_charge_swapin(memcg);
+               mem_cgroup_cancel_charge_swapin(memcg);
                ret = 0;
                goto out;
        }