]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: remove VM_LOCK_RMAP code
authorRik van Riel <riel@redhat.com>
Fri, 5 Mar 2010 21:42:10 +0000 (13:42 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 6 Mar 2010 19:26:26 +0000 (11:26 -0800)
commitfc148a5f7e0532750c312385c7ee9fa3e9311f34
treedfd132ed225a113f73c61f5e2018e5644bb3f677
parentc44b674323f4a2480dbeb65d4b487fa5f06f49e0
mm: remove VM_LOCK_RMAP code

When a VMA is in an inconsistent state during setup or teardown, the worst
that can happen is that the rmap code will not be able to find the page.

The mapping is in the process of being torn down (PTEs just got
invalidated by munmap), or set up (no PTEs have been instantiated yet).

It is also impossible for the rmap code to follow a pointer to an already
freed VMA, because the rmap code holds the anon_vma->lock, which the VMA
teardown code needs to take before the VMA is removed from the anon_vma
chain.

Hence, we should not need the VM_LOCK_RMAP locking at all.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/mm.h
mm/mmap.c
mm/rmap.c