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