[3.11.y.z extended stable] Patch "xen-netback: remove pointless clause from if statement" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    xen-netback: remove pointless clause from if statement

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 2e9d85534f5fbd5e81620ed7e90877b2dbafc9b9 Mon Sep 17 00:00:00 2001
From: Paul Durrant <Paul.Durrant at citrix.com>
Date: Fri, 28 Mar 2014 11:39:05 +0000
Subject: xen-netback: remove pointless clause from if statement

commit 0576eddf24df716d8570ef8ca11452a9f98eaab2 upstream.

This patch removes a test in start_new_rx_buffer() that checks whether
a copy operation is less than MAX_BUFFER_OFFSET in length, since
MAX_BUFFER_OFFSET is defined to be PAGE_SIZE and the only caller of
start_new_rx_buffer() already limits copy operations to PAGE_SIZE or less.

Signed-off-by: Paul Durrant <paul.durrant at citrix.com>
Cc: Ian Campbell <ian.campbell at citrix.com>
Cc: Wei Liu <wei.liu2 at citrix.com>
Cc: Sander Eikelenboom <linux at eikelenboom.it>
Reported-By: Sander Eikelenboom <linux at eikelenboom.it>
Tested-By: Sander Eikelenboom <linux at eikelenboom.it>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/xen-netback/netback.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index ac55997..3335983 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -354,8 +354,8 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head)
 	 * into multiple copies tend to give large frags their
 	 * own buffers as before.
 	 */
-	if ((offset + size > MAX_BUFFER_OFFSET) &&
-	    (size <= MAX_BUFFER_OFFSET) && offset && !head)
+	BUG_ON(size > MAX_BUFFER_OFFSET);
+	if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head)
 		return true;

 	return false;
--
1.9.1