[3.16.y-ckt stable] Patch "xen-netfront: respect user provided max_queues" has been added to the 3.16.y-ckt tree

[Luis Henriques]

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

    xen-netfront: respect user provided max_queues

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt24.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From 01e9c91271f523344ce3dc91b97514627756ed13 Mon Sep 17 00:00:00 2001
From: Wei Liu <wei.liu2 at citrix.com>
Date: Thu, 10 Sep 2015 11:18:58 +0100
Subject: xen-netfront: respect user provided max_queues

commit 32a844056fd43dda647e1c3c6b9983bdfa04d17d upstream.

Originally that parameter was always reset to num_online_cpus during
module initialisation, which renders it useless.

The fix is to only set max_queues to num_online_cpus when user has not
provided a value.

Signed-off-by: Wei Liu <wei.liu2 at citrix.com>
Cc: David Vrabel <david.vrabel at citrix.com>
Reviewed-by: David Vrabel <david.vrabel at citrix.com>
Tested-by: David Vrabel <david.vrabel at citrix.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/xen-netfront.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 9d3bdea182cd..2fb7f5d23608 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -2405,8 +2405,11 @@ static int __init netif_init(void)

 	pr_info("Initialising Xen virtual ethernet driver\n");

-	/* Allow as many queues as there are CPUs, by default */
-	xennet_max_queues = num_online_cpus();
+	/* Allow as many queues as there are CPUs if user has not
+	 * specified a value.
+	 */
+	if (xennet_max_queues == 0)
+		xennet_max_queues = num_online_cpus();

 	return xenbus_register_frontend(&netfront_driver);
 }