openwrtv4/target/linux/generic/patches-3.10/775-bgmac-check-length-of-received-frame.patch

From 2d12a9abf3f81de5b51852e3cfcba8cedac82642 Mon Sep 17 00:00:00 2001
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Fri, 6 Dec 2013 01:14:52 +0100
Subject: [PATCH] bgmac: check length of received frame

---
 drivers/net/ethernet/broadcom/bgmac.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -349,6 +349,7 @@ static int bgmac_dma_rx_read(struct bgma
 		struct sk_buff *skb = slot->skb;
 		struct bgmac_rx_header *rx;
 		u16 len, flags;
+		int count;
 
 		/* Unmap buffer to make it accessible to the CPU */
 		dma_sync_single_for_cpu(dma_dev, slot->dma_addr,
@@ -357,6 +358,12 @@ static int bgmac_dma_rx_read(struct bgma
 		/* Get info from the header */
 		rx = (struct bgmac_rx_header *)skb->data;
 		len = le16_to_cpu(rx->len);
+		for (count = 0; count < 200; count++) {
+			len = le16_to_cpu(rx->len);
+			if (len)
+				break;
+			udelay(1);
+		}
 		flags = le16_to_cpu(rx->flags);
 
 		do {
@@ -364,7 +371,7 @@ static int bgmac_dma_rx_read(struct bgma
 			int err;
 
 			/* Check for poison and drop or pass the packet */
-			if (len == 0xdead && flags == 0xbeef) {
+			if (!len || (len == 0xdead && flags == 0xbeef)) {
 				bgmac_err(bgmac, "Found poisoned packet at slot %d, DMA issue!\n",
 					  ring->start);
 				dma_sync_single_for_device(dma_dev,