From 18b461796b737f94286f73710debc8649467161b Mon Sep 17 00:00:00 2001
From: "Carlos E. Ugarte" <Carlos.E.Ugarte.1@gsfc.nasa.gov>
Date: Mon, 4 Jun 2007 11:49:19 -0400
Subject: [PATCH] ieee1394: fix to ether1394_tx in ether1394.c
This patch fixes a problem that occurs when packets cannot be sent across
the ieee1394 bus and we return NETDEV_TX_BUSY in the net driver "hard start
xmit" routine ether1394_tx. When we return NETDEV_TX_BUSY the stack will
call ether1394_tx again with the same skb. So we need to restore the header
to look like it did before we munged it for xmit over ieee1394.
[Stefan Richter: changed whitespace, deleted a local variable]
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
drivers/ieee1394/eth1394.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/ieee1394/eth1394.c b/drivers/ieee1394/eth1394.c
index 5f026b5d785..7c13fb3c167 100644
--- a/drivers/ieee1394/eth1394.c
+++ b/drivers/ieee1394/eth1394.c
@@ -1565,7 +1565,7 @@ static void ether1394_complete_cb(void *__ptask)
/* Transmit a packet (called by kernel) */
static int ether1394_tx(struct sk_buff *skb, struct net_device *dev)
{
- struct eth1394hdr *eth;
+ struct eth1394hdr hdr_buf;
struct eth1394_priv *priv = netdev_priv(dev);
__be16 proto;
unsigned long flags;
@@ -1595,16 +1595,17 @@ static int ether1394_tx(struct sk_buff *skb, struct net_device *dev)
if (!skb)
goto fail;
- /* Get rid of the fake eth1394 header, but save a pointer */
- eth = (struct eth1394hdr *)skb->data;
+ /* Get rid of the fake eth1394 header, but first make a copy.
+ * We might need to rebuild the header on tx failure. */
+ memcpy(&hdr_buf, skb->data, sizeof(hdr_buf));
skb_pull(skb, ETH1394_HLEN);
- proto = eth->h_proto;
+ proto = hdr_buf.h_proto;
dg_size = skb->len;
/* Set the transmission type for the packet. ARP packets and IP
* broadcast packets are sent via GASP. */
- if (memcmp(eth->h_dest, dev->broadcast, ETH1394_ALEN) == 0 ||
+ if (memcmp(hdr_buf.h_dest, dev->broadcast, ETH1394_ALEN) == 0 ||
proto == htons(ETH_P_ARP) ||
(proto == htons(ETH_P_IP) &&
IN_MULTICAST(ntohl(ip_hdr(skb)->daddr)))) {
@@ -1616,7 +1617,7 @@ static int ether1394_tx(struct sk_buff *skb, struct net_device *dev)
if (max_payload < dg_size + hdr_type_len[ETH1394_HDR_LF_UF])
priv->bc_dgl++;
} else {
- __be64 guid = get_unaligned((u64 *)eth->h_dest);
+ __be64 guid = get_unaligned((u64 *)hdr_buf.h_dest);
node = eth1394_find_node_guid(&priv->ip_node_list,
be64_to_cpu(guid));
@@ -1673,6 +1674,14 @@ static int ether1394_tx(struct sk_buff *skb, struct net_device *dev)
if (dest_node == (LOCAL_BUS | ALL_NODES))
goto fail;
+ /* At this point we want to restore the packet. When we return
+ * here with NETDEV_TX_BUSY we will get another entrance in this
+ * routine with the same skb and we need it to look the same.
+ * So we pull 4 more bytes, then build the header again. */
+ skb_pull(skb, 4);
+ ether1394_header(skb, dev, ntohs(hdr_buf.h_proto),
+ hdr_buf.h_dest, NULL, 0);
+
/* Most failures of ether1394_send_packet are recoverable. */
netif_stop_queue(dev);
priv->wake_node = dest_node;
--
2.20.1