The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4993e5b37e8bcb55ac90f76eb6d2432647273747 Mon Sep 17 00:00:00 2001

From: Jose Abreu Jose.Abreu@synopsys.com Date: Mon, 8 Jul 2019 14:26:28 +0200 Subject: [PATCH] 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: c5acdbee22a1 ("net: stmmac: Send TSO packets always from Queue 0") Suggested-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Jose Abreu joabreu@synopsys.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 06358fe5b245..11b6feb33b54 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -3045,17 +3045,8 @@ 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)) { @@ -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