mm/nommu: remove unnecessary VMA locking

Since CONFIG_PER_VMA_LOCK depends on CONFIG_MMU, the changes in nommu are
not needed.  Remove them.

Link: https://lkml.kernel.org/r/20230301190457.1498985-1-surenb@google.com
Fixes: bad94decd6a4 ("mm: write-lock VMAs before removing them from VMA tree")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Link: https://lore.kernel.org/all/Y%2F8CJQGNuMUTdLwP@localhost/
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/nommu.c b/mm/nommu.c
index 2ab162d773e217264e85c5a95668ac8d2bd6d999..57ba243c6a37f466962891f6d71b7dc0910ffce7 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -588,7 +588,6 @@ static int delete_vma_from_mm(struct vm_area_struct *vma)
                       current->pid);
                return -ENOMEM;
        }
-       vma_start_write(vma);
        cleanup_vma_from_mm(vma);
 
        /* remove from the MM's tree and list */
@@ -1520,10 +1519,6 @@ void exit_mmap(struct mm_struct *mm)
         */
        mmap_write_lock(mm);
        for_each_vma(vmi, vma) {
-               /*
-                * No need to lock VMA because this is the only mm user and no
-                * page fault handled can race with it.
-                */
                cleanup_vma_from_mm(vma);
                delete_vma(mm, vma);
                cond_resched();