From: Michael S. Tsirkin <mst@redhat.com>
Date: Sun, 6 Mar 2011 11:33:49 +0000 (+0200)
Subject: vhost: copy_from_user -> __copy_from_user
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=fcc042a2806064ffcaed7a0c5cb710eca0e99108;p=mv-sheeva.git

vhost: copy_from_user -> __copy_from_user

copy_from_user is pretty high on perf top profile,
replacing it with __copy_from_user helps.
It's also safe because we do access_ok checks during setup.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b0cc7f8ca4d..2ab29124163 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1171,7 +1171,7 @@ int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
 			       i, vq->num, head);
 			return -EINVAL;
 		}
-		ret = copy_from_user(&desc, vq->desc + i, sizeof desc);
+		ret = __copy_from_user(&desc, vq->desc + i, sizeof desc);
 		if (unlikely(ret)) {
 			vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
 			       i, vq->desc + i);