Patch "net: alx: Work around the DMA RX overflow issue" has been added to the 3.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    net: alx: Work around the DMA RX overflow issue

to the 3.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-alx-work-around-the-dma-rx-overflow-issue.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Jul  6 17:30:58 PDT 2016
From: Feng Tang <feng.tang@intel.com>
Date: Fri, 24 Jun 2016 15:26:05 +0800
Subject: net: alx: Work around the DMA RX overflow issue
Status: RO
Content-Length: 1764
Lines: 47

From: Feng Tang <feng.tang@intel.com>

[ Upstream commit 881d0327db37ad917a367c77aff1afa1ee41e0a9 ]

Note: This is a verified backported patch for stable 4.4 kernel, and it
could also be applied to 4.3/4.2/4.1/3.18/3.16

There is a problem with alx devices, that the network link will be
lost in 1-5 minutes after the device is up.

>>From debugging without datasheet, we found the error always
happen when the DMA RX address is set to 0x....fc0, which is very
likely to be a HW/silicon problem.

This patch will apply rx skb with 64 bytes longer space, and if the
allocated skb has a 0x...fc0 address, it will use skb_resever(skb, 64)
to advance the address, so that the RX overflow can be avoided.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=70761
Signed-off-by: Feng Tang <feng.tang@intel.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Tested-by: Ole Lukoie <olelukoie@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/atheros/alx/main.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/drivers/net/ethernet/atheros/alx/main.c
@@ -86,9 +86,14 @@ static int alx_refill_rx_ring(struct alx
 	while (!cur_buf->skb && next != rxq->read_idx) {
 		struct alx_rfd *rfd = &rxq->rfd[cur];
 
-		skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size, gfp);
+		skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size + 64, gfp);
 		if (!skb)
 			break;
+
+		/* Workround for the HW RX DMA overflow issue */
+		if (((unsigned long)skb->data & 0xfff) == 0xfc0)
+			skb_reserve(skb, 64);
+
 		dma = dma_map_single(&alx->hw.pdev->dev,
 				     skb->data, alx->rxbuf_size,
 				     DMA_FROM_DEVICE);


Patches currently in stable-queue which might be from feng.tang@intel.com are

queue-3.14/net-alx-work-around-the-dma-rx-overflow-issue.patch