Ensure that the skb is not cloned and has enough tail room for the tail
tag. This code will be removed from the drivers in the next commits.
Signed-off-by: Christian Eggers <cegg...@arri.de>
---
net/dsa/dsa_priv.h | 3 +++
net/dsa/slave.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 12998bf04e55..975001c625b1 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -77,6 +77,9 @@ struct dsa_slave_priv {
/* Copy of CPU port xmit for faster access in slave transmit hot path */
struct sk_buff * (*xmit)(struct sk_buff *skb,
struct net_device *dev);
+ /* same for tail_tag and overhead */
+ bool tail_tag;
+ unsigned int overhead;
struct pcpu_sw_netstats __percpu *stats64;
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 3bc5ca40c9fb..49a19a3b0736 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -553,6 +553,7 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb,
struct net_device *dev)
struct dsa_slave_priv *p = netdev_priv(dev);
struct pcpu_sw_netstats *s;
struct sk_buff *nskb;
+ int padlen;
s = this_cpu_ptr(p->stats64);
u64_stats_update_begin(&s->syncp);
@@ -567,6 +568,41 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb,
struct net_device *dev)
*/
dsa_skb_tx_timestamp(p, skb);
+ /* We have to pad he packet to the minimum Ethernet frame size,
+ * if necessary, before adding the trailer (tail tagging only).
+ */
+ padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
+
+ /* To keep the slave's xmit() methods simple, don't pass cloned skbs to
+ * them. Additionally ensure, that suitable room for tail tagging is
+ * available.
+ */
+ if (skb_cloned(skb) ||
+ (p->tail_tag && skb_tailroom(skb) < (padlen + p->overhead))) {
+ struct sk_buff *nskb;
+
+ nskb = alloc_skb(NET_IP_ALIGN + skb->len +
+ padlen + p->overhead, GFP_ATOMIC);
+ if (!nskb) {
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+ }
+ skb_reserve(nskb, NET_IP_ALIGN);
+
+ skb_reset_mac_header(nskb);
+ skb_set_network_header(nskb,
+ skb_network_header(skb) - skb->head);
+ skb_set_transport_header(nskb,
+ skb_transport_header(skb) - skb->head);
+ skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
+ consume_skb(skb);
+
+ if (padlen)
+ skb_put_zero(nskb, padlen);
+
+ skb = nskb;
+ }
+
/* Transmit function may have to reallocate the original SKB,
* in which case it must have freed it. Only free it here on error.
*/
@@ -1814,6 +1850,8 @@ int dsa_slave_create(struct dsa_port *port)
p->dp = port;
INIT_LIST_HEAD(&p->mall_tc_list);
p->xmit = cpu_dp->tag_ops->xmit;
+ p->tail_tag = cpu_dp->tag_ops->tail_tag;
+ p->overhead = cpu_dp->tag_ops->overhead;
port->slave = slave_dev;
rtnl_lock();
--
Christian Eggers
Embedded software developer
Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer:
HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer:
HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger;
Markus Zeiler
