[ 3.8.y.z extended stable ] Patch "atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring" has been added to staging queue

[Kamal Mostafa]

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

    atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.7.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 797217540b4cd9e4d119a533ce7b6693c926064f Mon Sep 17 00:00:00 2001
From: Neil Horman <nhorman at tuxdriver.com>
Date: Fri, 26 Jul 2013 12:47:14 -0400
Subject: atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring

commit ebe7fdbaf3e90ea22feade6c9f5e50f42b23b6d8 upstream.

atl1c uses netdev_alloc_skb to refill its rx dma ring, but that call makes no
guarantees about the suitability of the memory for use in DMA.  As a result
we've gotten reports of atl1c drivers occasionally hanging and needing to be
reset:
https://bugzilla.kernel.org/show_bug.cgi?id=54021

Fix this by modifying the call to use the internal version __netdev_alloc_skb,
where you can set the gfp_mask explicitly to include GFP_DMA.

Tested by two reporters in the above bug, who have the hardware to validate it.
Both report immediate cessation of the problem with this patch

Signed-off-by: Neil Horman <nhorman at tuxdriver.com>
CC: Jay Cliburn <jcliburn at gmail.com>
CC: "David S. Miller" <davem at davemloft.net>
Tested-by: Luis Henriques <luis.henriques at canonical.com>
Tested-by: Vincent Alquier <vincent.alquier at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/ethernet/atheros/atl1c/atl1c_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
index bfcb8bc..4e438ff 100644
--- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
@@ -1663,7 +1663,7 @@ static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
 	while (next_info->flags & ATL1C_BUFFER_FREE) {
 		rfd_desc = ATL1C_RFD_DESC(rfd_ring, rfd_next_to_use);

-		skb = netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len);
+		skb = __netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len, GFP_ATOMIC|GFP_DMA);
 		if (unlikely(!skb)) {
 			if (netif_msg_rx_err(adapter))
 				dev_warn(&pdev->dev, "alloc rx buffer failed\n");
--
1.8.1.2