mremap: don't do uneccesary checks if new_len == old_len
authorOleg Nesterov <oleg@redhat.com>
Fri, 4 Sep 2015 22:48:10 +0000 (15:48 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 4 Sep 2015 23:54:41 +0000 (16:54 -0700)
commit1d3916869798755968b3cd764ab21f2bb86ffff7
treed8a9baa17fab65069a49000cfe4c741982f1ccfe
parentd456fb9e5254df433d4806769d7ff75d80d66aa4
mremap: don't do uneccesary checks if new_len == old_len

The "new_len > old_len" branch in vma_to_resize() looks very confusing.
It only covers the VM_DONTEXPAND/pgoff checks but everything below is
equally unneeded if new_len == old_len.

Change this code to return if "new_len == old_len", new_len < old_len is
not possible, otherwise the code below is wrong anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/mremap.c