tree 8d480975d95adf85f3a87dd478e36e4ac0b0edd0
parent 1d678f365dae28420fa7329a2a35390b3582678d
author Manfred Spraul <manfred@colorfullife.com> 1228166042 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1228190125 -0800

lib/idr.c: fix rcu related race with idr_find

2nd part of the fixes needed for
http://bugzilla.kernel.org/show_bug.cgi?id=11796.

When the idr tree is either grown or shrunk, then the update to the number
of layers and the top pointer were not atomic.  This race caused crashes.

The attached patch fixes that by replicating the layers counter in each
layer, thus idr_find doesn't need idp->layers anymore.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Clement Calmels <cboulte@gmail.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>