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

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 [off-list ref] know about it.

From foo@baz Wed Jul  6 17:30:58 PDT 2016

From: Feng Tang <redacted>
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 <redacted>

[ 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.

quoted

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 <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>
Tested-by: Ole Lukoie <redacted>
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