mm/mmap.c: don't unlock VMAs in remap_file_pages()

Since this call uses MAP_FIXED, do_mmap() will munlock the necessary
range.  There is also an error in the loop test expression which will
evaluate as false and the loop body has never execute.

Link: https://lkml.kernel.org/r/20210223235010.2296915-1-Liam.Howlett@Oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index 347ef9b..c1b848f 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3029,25 +3029,9 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 
        flags &= MAP_NONBLOCK;
        flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
-       if (vma->vm_flags & VM_LOCKED) {
-               struct vm_area_struct *tmp;
+       if (vma->vm_flags & VM_LOCKED)
                flags |= MAP_LOCKED;
 
-               /* drop PG_Mlocked flag for over-mapped range */
-               for (tmp = vma; tmp->vm_start >= start + size;
-                               tmp = tmp->vm_next) {
-                       /*
-                        * Split pmd and munlock page on the border
-                        * of the range.
-                        */
-                       vma_adjust_trans_huge(tmp, start, start + size, 0);
-
-                       munlock_vma_pages_range(tmp,
-                                       max(tmp->vm_start, start),
-                                       min(tmp->vm_end, start + size));
-               }
-       }
-
        file = get_file(vma->vm_file);
        ret = do_mmap(vma->vm_file, start, size,
                        prot, flags, pgoff, &populate, NULL);