tree 2a0c920af1a2a7f748d81248cb027ca12f7f0bb5
parent e403d295817cf9f8be3110eb7ee1a03981287495
author Jason Wang <jasowang@redhat.com> 1370476473 +0000
committer David S. Miller <davem@davemloft.net> 1370674148 -0700

macvtap: fix a possible race between queue selection and changing queues

Complier may generate codes that re-read the vlan->numvtaps during
macvtap_get_queue(). This may lead a race if vlan->numvtaps were changed in the
same time and which can lead unexpected result (e.g. very huge value).

We need prevent the compiler from generating such codes by adding an
ACCESS_ONCE() to make sure vlan->numvtaps were only read once.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>