From fcc042a2806064ffcaed7a0c5cb710eca0e99108 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Sun, 6 Mar 2011 13:33:49 +0200
Subject: [PATCH] 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>
---
drivers/vhost/vhost.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b0cc7f8ca4de..2ab291241635 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);
--
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