Linux Virtualization - Feb 2015 - [PATCH] vhost: drop hard-coded num_buffers size

The 2 that we use for copy_to_iter comes from sizeof(u16),
it used to be that way before the iov iter update.
Fix it up, making it obvious the size of stack access
is right.

Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
 drivers/vhost/net.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ca70434..2bbfc25 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -621,7 +621,8 @@ static void handle_rx(struct vhost_net *net)
 
 		num_buffers = cpu_to_vhost16(vq, headcount);
 		if (likely(mergeable) &&
-		    copy_to_iter(&num_buffers, 2, &fixup) != 2) {
+		    copy_to_iter(&num_buffers, sizeof num_buffers,
+				 &fixup) != sizeof num_buffers) {
 			vq_err(vq, "Failed num_buffers write");
 			vhost_discard_vq_desc(vq, headcount);
 			break;
-- 
MST

From: "Michael S. Tsirkin" <mst at redhat.com>
Date: Tue, 24 Feb 2015 17:31:10 +0100
> The 2 that we use for copy_to_iter comes from sizeof(u16),
> it used to be that way before the iov iter update.
> Fix it up, making it obvious the size of stack access
> is right.
> 
> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Michael, what tree do you want these two patches to go through?

On Wed, Feb 25, 2015 at 04:56:52PM -0500, David Miller
wrote:
> From: "Michael S. Tsirkin" <mst at redhat.com>
> Date: Tue, 24 Feb 2015 17:31:10 +0100
> 
> > The 2 that we use for copy_to_iter comes from sizeof(u16),
> > it used to be that way before the iov iter update.
> > Fix it up, making it obvious the size of stack access
> > is right.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
> 
> Michael, what tree do you want these two patches to go through?
Sorry about being unclear.
They are net specific so I'd like them merged for 4.0 through net tree.
If that's a problem, pls let me know.

Thanks,
-- 
MST

From: "Michael S. Tsirkin" <mst at redhat.com>
Date: Tue, 24 Feb 2015 17:31:10 +0100
> The 2 that we use for copy_to_iter comes from sizeof(u16),
> it used to be that way before the iov iter update.
> Fix it up, making it obvious the size of stack access
> is right.
> 
> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Applied.