From eae792b722fef08dcf3aee88266ee7def9710757 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 15 Jul 2008 03:03:33 -0700 Subject: netdev: Add netdev->select_queue() method. Devices or device layers can set this to control the queue selection performed by dev_pick_tx(). This function runs under RCU protection, which allows overriding functions to have some way of synchronizing with things like dynamic ->real_num_tx_queues adjustments. This makes the spinlock prefetch in dev_queue_xmit() a little bit less effective, but that's the price right now for correctness. Signed-off-by: David S. Miller --- net/core/dev.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'net/core') diff --git a/net/core/dev.c b/net/core/dev.c index f027a1ac4fbb..7ca9564d2f44 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1670,6 +1670,9 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev, { u16 queue_index = 0; + if (dev->select_queue) + queue_index = dev->select_queue(dev, skb); + skb_set_queue_mapping(skb, queue_index); return netdev_get_tx_queue(dev, queue_index); } @@ -1710,14 +1713,14 @@ int dev_queue_xmit(struct sk_buff *skb) } gso: - txq = dev_pick_tx(dev, skb); - spin_lock_prefetch(&txq->lock); - /* Disable soft irqs for various locks below. Also * stops preemption for RCU. */ rcu_read_lock_bh(); + txq = dev_pick_tx(dev, skb); + spin_lock_prefetch(&txq->lock); + /* Updates of qdisc are serialized by queue->lock. * The struct Qdisc which is pointed to by qdisc is now a * rcu structure - it may be accessed without acquiring -- cgit v1.2.3