mm: enable maple tree RCU mode by default.

we don't need to free the nodes with RCU

Link: https://lkml.kernel.org/r/20230227173632.3292573-9-surenb@google.com
Link: https://lore.kernel.org/linux-mm/000000000000b0a65805f663ace6@google.com/
Link: https://lkml.kernel.org/r/20230327185532.2354250-9-Liam.Howlett@oracle.com
Cc: stable@vger.kernel.org
Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: syzbot+8d95422d3537159ca390@syzkaller.appspotmail.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index a30e8a784b5371c19882e5a43d576df1f25f3f27..ff68a67a2a7c3477fa19c93d740a3f26617545b9 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2277,8 +2277,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
        int count = 0;
        int error = -ENOMEM;
        MA_STATE(mas_detach, &mt_detach, 0, 0);
-       mt_init_flags(&mt_detach, vmi->mas.tree->ma_flags &
-                     (MT_FLAGS_LOCK_MASK | MT_FLAGS_USE_RCU));
+       mt_init_flags(&mt_detach, vmi->mas.tree->ma_flags & MT_FLAGS_LOCK_MASK);
        mt_set_external_lock(&mt_detach, &mm->mmap_lock);
 
        /*