From: Michael S. Tsirkin <mst@redhat.com>
Date: Tue, 9 Jul 2013 10:19:18 +0000 (+0300)
Subject: virtio: support unlocked queue poll
X-Git-Tag: v3.2.50~57
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1e079ec5c16199e63c9c5e0e346a0fdf47681f32;p=pandora-kernel.git

virtio: support unlocked queue poll

commit cc229884d3f77ec3b1240e467e0236c3e0647c0c upstream.

This adds a way to check ring empty state after enable_cb outside any
locks. Will be used by virtio_net.

Note: there's room for more optimization: caller is likely to have a
memory barrier already, which means we might be able to get rid of a
barrier here.  Deferring this optimization until we do some
benchmarking.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[wg: Backported to 3.2]
Signed-off-by: Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

Reading git-diff-tree failed