[PATCH v2 net-next 5/9] net: dsa: tag_ksz: do not rely on skb_mac_header() in TX paths

From: Vladimir Oltean
Date: Thu Apr 20 2023 - 18:56:41 EST


skb_mac_header() will no longer be available in the TX path when
reverting commit 6d1ccff62780 ("net: reset mac header in
dev_start_xmit()"). As preparation for that, let's use skb_eth_hdr() to
get to the Ethernet header's MAC DA instead, helper which assumes this
header is located at skb->data (assumption which holds true here).

Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
net/dsa/tag_ksz.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index 0eb1c7784c3d..ea100bd25939 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -120,18 +120,18 @@ static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
+ struct ethhdr *hdr;
u8 *tag;
- u8 *addr;

if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
return NULL;

/* Tag encoding */
tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
- addr = skb_mac_header(skb);
+ hdr = skb_eth_hdr(skb);

*tag = 1 << dp->index;
- if (is_link_local_ether_addr(addr))
+ if (is_link_local_ether_addr(hdr->h_dest))
*tag |= KSZ8795_TAIL_TAG_OVERRIDE;

return skb;
@@ -273,8 +273,8 @@ static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
u16 queue_mapping = skb_get_queue_mapping(skb);
u8 prio = netdev_txq_to_tc(dev, queue_mapping);
struct dsa_port *dp = dsa_slave_to_port(dev);
+ struct ethhdr *hdr;
__be16 *tag;
- u8 *addr;
u16 val;

if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
@@ -284,13 +284,13 @@ static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
ksz_xmit_timestamp(dp, skb);

tag = skb_put(skb, KSZ9477_INGRESS_TAG_LEN);
- addr = skb_mac_header(skb);
+ hdr = skb_eth_hdr(skb);

val = BIT(dp->index);

val |= FIELD_PREP(KSZ9477_TAIL_TAG_PRIO, prio);

- if (is_link_local_ether_addr(addr))
+ if (is_link_local_ether_addr(hdr->h_dest))
val |= KSZ9477_TAIL_TAG_OVERRIDE;

*tag = cpu_to_be16(val);
@@ -337,7 +337,7 @@ static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
u16 queue_mapping = skb_get_queue_mapping(skb);
u8 prio = netdev_txq_to_tc(dev, queue_mapping);
struct dsa_port *dp = dsa_slave_to_port(dev);
- u8 *addr;
+ struct ethhdr *hdr;
u8 *tag;

if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
@@ -347,13 +347,13 @@ static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
ksz_xmit_timestamp(dp, skb);

tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
- addr = skb_mac_header(skb);
+ hdr = skb_eth_hdr(skb);

*tag = BIT(dp->index);

*tag |= FIELD_PREP(KSZ9893_TAIL_TAG_PRIO, prio);

- if (is_link_local_ether_addr(addr))
+ if (is_link_local_ether_addr(hdr->h_dest))
*tag |= KSZ9893_TAIL_TAG_OVERRIDE;

return ksz_defer_xmit(dp, skb);
--
2.34.1