From: Krishna Kumar Date: Thu, 15 Nov 2007 05:05:37 +0000 (+0530) Subject: IPoIB: Remove redundant check of netif_queue_stopped() in xmit handler X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=48fe5e594c979177b7f20affd027be56e8ea2767;p=openwrt%2Fstaging%2Fblogic.git IPoIB: Remove redundant check of netif_queue_stopped() in xmit handler qdisc_run() now tests for queue_stopped() before calling __qdisc_run(), and the same check is done in every iteration of __qdisc_run(), so another check is not required in the driver xmit. This means that ipoib_start_xmit() no longer needs to test netif_queue_stopped(); the test was added to fix earlier kernels, where the networking stack did not guarantee that the xmit method of an LLTX driver would not be called after the queue was stopped, but current kernels do provide this guarantee. To validate, I put a debug in the TX_BUSY path which never hit with 64 threads running overnight exercising this code a few 100 million times. Signed-off-by: Krishna Kumar Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c index d7330451685c..a082466f4a83 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -672,16 +672,6 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev) if (unlikely(!spin_trylock_irqsave(&priv->tx_lock, flags))) return NETDEV_TX_LOCKED; - /* - * Check if our queue is stopped. Since we have the LLTX bit - * set, we can't rely on netif_stop_queue() preventing our - * xmit function from being called with a full queue. - */ - if (unlikely(netif_queue_stopped(dev))) { - spin_unlock_irqrestore(&priv->tx_lock, flags); - return NETDEV_TX_BUSY; - } - if (likely(skb->dst && skb->dst->neighbour)) { if (unlikely(!*to_ipoib_neigh(skb->dst->neighbour))) { ipoib_path_lookup(skb, dev);