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Commit 4993e5b3 authored by Jose Abreu's avatar Jose Abreu Committed by David S. Miller
Browse files

net: stmmac: Re-work the queue selection for TSO packets 



Ben Hutchings says:
	"This is the wrong place to change the queue mapping.
	stmmac_xmit() is called with a specific TX queue locked,
	and accessing a different TX queue results in a data race
	for all of that queue's state.

	I think this commit should be reverted upstream and in all
	stable branches.  Instead, the driver should implement the
	ndo_select_queue operation and override the queue mapping there."

Fixes: c5acdbee ("net: stmmac: Send TSO packets always from Queue 0")
Suggested-by: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarJose Abreu <joabreu@synopsys.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 36c4357c

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+18 −10
Original line number Diff line number Diff line
@@ -3045,18 +3045,9 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) 


	/* Manage oversized TCP frames for GMAC4 device */

	if (skb_is_gso(skb) && priv->tso) {

		if (skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)) {

			/*

			 * There is no way to determine the number of TSO

			 * capable Queues. Let's use always the Queue 0

			 * because if TSO is supported then at least this

			 * one will be capable.

			 */

			skb_set_queue_mapping(skb, 0);



		if (skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))

			return stmmac_tso_xmit(skb, dev);

	}

	}



	if (unlikely(stmmac_tx_avail(priv, queue) < nfrags + 1)) {

		if (!netif_tx_queue_stopped(netdev_get_tx_queue(dev, queue))) {
@@ -3872,6 +3863,22 @@ static int stmmac_setup_tc(struct net_device *ndev, enum tc_setup_type type, 
	}

}



static u16 stmmac_select_queue(struct net_device *dev, struct sk_buff *skb,

			       struct net_device *sb_dev)

{

	if (skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)) {

		/*

		 * There is no way to determine the number of TSO

		 * capable Queues. Let's use always the Queue 0

		 * because if TSO is supported then at least this

		 * one will be capable.

		 */

		return 0;

	}



	return netdev_pick_tx(dev, skb, NULL) % dev->real_num_tx_queues;

}



static int stmmac_set_mac_address(struct net_device *ndev, void *addr)

{

	struct stmmac_priv *priv = netdev_priv(ndev);
@@ -4088,6 +4095,7 @@ static const struct net_device_ops stmmac_netdev_ops = { 
	.ndo_tx_timeout = stmmac_tx_timeout,

	.ndo_do_ioctl = stmmac_ioctl,

	.ndo_setup_tc = stmmac_setup_tc,

	.ndo_select_queue = stmmac_select_queue,

#ifdef CONFIG_NET_POLL_CONTROLLER

	.ndo_poll_controller = stmmac_poll_controller,

#endif