diff options
Diffstat (limited to 'target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch')
| -rw-r--r-- | target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch b/target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch new file mode 100644 index 0000000000..4171a69d1d --- /dev/null +++ b/target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch @@ -0,0 +1,104 @@ +From a3b0b6479700a5b0af2c631cb2ec0fb7a0d978f2 Mon Sep 17 00:00:00 2001 +From: Vladimir Oltean <vladimir.oltean@nxp.com> +Date: Sun, 1 Nov 2020 21:16:09 +0200 +Subject: [PATCH] net: dsa: implement a central TX reallocation procedure + +At the moment, taggers are left with the task of ensuring that the skb +headers are writable (which they aren't, if the frames were cloned for +TX timestamping, for flooding by the bridge, etc), and that there is +enough space in the skb data area for the DSA tag to be pushed. + +Moreover, the life of tail taggers is even harder, because they need to +ensure that short frames have enough padding, a problem that normal +taggers don't have. + +The principle of the DSA framework is that everything except for the +most intimate hardware specifics (like in this case, the actual packing +of the DSA tag bits) should be done inside the core, to avoid having +code paths that are very rarely tested. + +So provide a TX reallocation procedure that should cover the known needs +of DSA today. + +Note that this patch also gives the network stack a good hint about the +headroom/tailroom it's going to need. Up till now it wasn't doing that. +So the reallocation procedure should really be there only for the +exceptional cases, and for cloned packets which need to be unshared. + +Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> +Tested-by: Christian Eggers <ceggers@arri.de> # For tail taggers only +Tested-by: Kurt Kanzenbach <kurt@linutronix.de> +Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> +Signed-off-by: Jakub Kicinski <kuba@kernel.org> +--- + net/dsa/slave.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ + 1 file changed, 45 insertions(+) + +--- a/net/dsa/slave.c ++++ b/net/dsa/slave.c +@@ -548,6 +548,30 @@ netdev_tx_t dsa_enqueue_skb(struct sk_bu + } + EXPORT_SYMBOL_GPL(dsa_enqueue_skb); + ++static int dsa_realloc_skb(struct sk_buff *skb, struct net_device *dev) ++{ ++ int needed_headroom = dev->needed_headroom; ++ int needed_tailroom = dev->needed_tailroom; ++ ++ /* For tail taggers, we need to pad short frames ourselves, to ensure ++ * that the tail tag does not fail at its role of being at the end of ++ * the packet, once the master interface pads the frame. Account for ++ * that pad length here, and pad later. ++ */ ++ if (unlikely(needed_tailroom && skb->len < ETH_ZLEN)) ++ needed_tailroom += ETH_ZLEN - skb->len; ++ /* skb_headroom() returns unsigned int... */ ++ needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0); ++ needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0); ++ ++ if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb))) ++ /* No reallocation needed, yay! */ ++ return 0; ++ ++ return pskb_expand_head(skb, needed_headroom, needed_tailroom, ++ GFP_ATOMIC); ++} ++ + static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev) + { + struct dsa_slave_priv *p = netdev_priv(dev); +@@ -567,6 +591,17 @@ static netdev_tx_t dsa_slave_xmit(struct + */ + dsa_skb_tx_timestamp(p, skb); + ++ if (dsa_realloc_skb(skb, dev)) { ++ dev_kfree_skb_any(skb); ++ return NETDEV_TX_OK; ++ } ++ ++ /* needed_tailroom should still be 'warm' in the cache line from ++ * dsa_realloc_skb(), which has also ensured that padding is safe. ++ */ ++ if (dev->needed_tailroom) ++ eth_skb_pad(skb); ++ + /* Transmit function may have to reallocate the original SKB, + * in which case it must have freed it. Only free it here on error. + */ +@@ -1825,6 +1860,16 @@ int dsa_slave_create(struct dsa_port *po + slave_dev->netdev_ops = &dsa_slave_netdev_ops; + if (ds->ops->port_max_mtu) + slave_dev->max_mtu = ds->ops->port_max_mtu(ds, port->index); ++ if (cpu_dp->tag_ops->tail_tag) ++ slave_dev->needed_tailroom = cpu_dp->tag_ops->overhead; ++ else ++ slave_dev->needed_headroom = cpu_dp->tag_ops->overhead; ++ /* Try to save one extra realloc later in the TX path (in the master) ++ * by also inheriting the master's needed headroom and tailroom. ++ * The 8021q driver also does this. ++ */ ++ slave_dev->needed_headroom += master->needed_headroom; ++ slave_dev->needed_tailroom += master->needed_tailroom; + SET_NETDEV_DEVTYPE(slave_dev, &dsa_type); + + netdev_for_each_tx_queue(slave_dev, dsa_slave_set_lockdep_class_one, |