From 9eb8bc593a5eed167dac2029abef343854c5ba75 Mon Sep 17 00:00:00 2001 From: DENG Qingfang Date: Mon, 1 Mar 2021 01:08:23 +0800 Subject: net: dsa: tag_rtl4_a: fix egress tags Commit 86dd9868b878 has several issues, but was accepted too soon before anyone could take a look. - Double free. dsa_slave_xmit() will free the skb if the xmit function returns NULL, but the skb is already freed by eth_skb_pad(). Use __skb_put_padto() to avoid that. - Unnecessary allocation. It has been done by DSA core since commit a3b0b6479700. - A u16 pointer points to skb data. It should be __be16 for network byte order. - Typo in comments. "numer" -> "number". Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags") Signed-off-by: DENG Qingfang Reviewed-by: Florian Fainelli Reviewed-by: Linus Walleij Signed-off-by: David S. Miller --- net/dsa/tag_rtl4_a.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'net/dsa/tag_rtl4_a.c') diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c index c17d39b4a1a0..e9176475bac8 100644 --- a/net/dsa/tag_rtl4_a.c +++ b/net/dsa/tag_rtl4_a.c @@ -35,14 +35,12 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); + __be16 *p; u8 *tag; - u16 *p; u16 out; /* Pad out to at least 60 bytes */ - if (unlikely(eth_skb_pad(skb))) - return NULL; - if (skb_cow_head(skb, RTL4_A_HDR_LEN) < 0) + if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false))) return NULL; netdev_dbg(dev, "add realtek tag to package to port %d\n", @@ -53,13 +51,13 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb, tag = skb->data + 2 * ETH_ALEN; /* Set Ethertype */ - p = (u16 *)tag; + p = (__be16 *)tag; *p = htons(RTL4_A_ETHERTYPE); out = (RTL4_A_PROTOCOL_RTL8366RB << 12) | (2 << 8); - /* The lower bits is the port numer */ + /* The lower bits is the port number */ out |= (u8)dp->index; - p = (u16 *)(tag + 2); + p = (__be16 *)(tag + 2); *p = htons(out); return skb; -- cgit v1.2.3