From: Gerrit Renker Date: Sat, 17 May 2008 07:35:36 +0000 (+0100) Subject: [SC92031] Using padto turned driver into an IPv6-only interface X-Git-Tag: v2.6.26-rc4~7^2~1^2~20 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5a0a92e67b5009a71e011658da04fb92dad8961f;p=linux-2.6 [SC92031] Using padto turned driver into an IPv6-only interface IPv4 would work with this driver only with static arp table entries, the patch reverts a padto introduced in commit 26a17b7bbb36a8552d531bc1ad08472fb5aa3007 sc92031: start transmit return value bugfix The padto does not work because the driver code evaluates `len' later on and there are cases where skb->len is not updated accordingly. This was observed with ARP frames (skb->len = 42 bytes, !skb_cloned(), skb_tailroom = 84 bytes). Then in skb_pad(), the first condition is true, where skb->len is not updated. As a consequence, the driver uses 42 bytes instead of the 60 bytes, and the ARP frame never makes it onto the wire. Signed-off-by: Gerrit Renker Signed-off-by: Jeff Garzik --- diff --git a/drivers/net/sc92031.c b/drivers/net/sc92031.c index f64a860029..b4b63805ee 100644 --- a/drivers/net/sc92031.c +++ b/drivers/net/sc92031.c @@ -953,9 +953,6 @@ static int sc92031_start_xmit(struct sk_buff *skb, struct net_device *dev) unsigned entry; u32 tx_status; - if (skb_padto(skb, ETH_ZLEN)) - return NETDEV_TX_OK; - if (unlikely(skb->len > TX_BUF_SIZE)) { dev->stats.tx_dropped++; goto out; @@ -975,6 +972,11 @@ static int sc92031_start_xmit(struct sk_buff *skb, struct net_device *dev) skb_copy_and_csum_dev(skb, priv->tx_bufs + entry * TX_BUF_SIZE); len = skb->len; + if (unlikely(len < ETH_ZLEN)) { + memset(priv->tx_bufs + entry * TX_BUF_SIZE + len, + 0, ETH_ZLEN - len); + len = ETH_ZLEN; + } wmb();