swapfile rcu fix

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 3992959c087251c2fa1bd42c7eb9666c545d01d1..5c2a2615e83547268e4cada9f085643117cfe623 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2105,6 +2105,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type,
        MA_STATE(mas, &mm->mm_mt, 0, 0);
 
        mmap_read_lock(mm);
+       mas_lock(&mas);
        mas_for_each(&mas, vma, ULONG_MAX) {
                if (vma->anon_vma) {
                        ret = unuse_vma(vma, type, frontswap,
@@ -2112,8 +2113,13 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type,
                        if (ret)
                                break;
                }
+
+               mas_unlock(&mas);
+               mas_pause(&mas);
                cond_resched();
+               mas_lock(&mas);
        }
+       mas_unlock(&mas);
        mmap_read_unlock(mm);
        return ret;
 }