From: Chris Leech Date: Wed, 2 Aug 2006 21:21:19 +0000 (-0700) Subject: [I/OAT]: Remove CPU hotplug lock from net_dma_rebalance X-Git-Tag: v2.6.18-rc4~65^2~2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=e6eb307d48c81d688804f8b39a0a3ddde3cd3458;p=linux-2.6-block.git [I/OAT]: Remove CPU hotplug lock from net_dma_rebalance Remove the lock_cpu_hotplug()/unlock_cpu_hotplug() calls from net_dma_rebalance The lock_cpu_hotplug()/unlock_cpu_hotplug() sequence in net_dma_rebalance is both incorrect (as pointed out by David Miller) because lock_cpu_hotplug() may sleep while the net_dma_event_lock spinlock is held, and unnecessary (as pointed out by Andrew Morton) as spin_lock() disables preemption which protects from CPU hotplug events. Signed-off-by: Chris Leech Signed-off-by: David S. Miller --- diff --git a/net/core/dev.c b/net/core/dev.c index 5b630cece707..f25d7ecaf035 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3419,12 +3419,9 @@ static void net_dma_rebalance(void) unsigned int cpu, i, n; struct dma_chan *chan; - lock_cpu_hotplug(); - if (net_dma_count == 0) { for_each_online_cpu(cpu) rcu_assign_pointer(per_cpu(softnet_data.net_dma, cpu), NULL); - unlock_cpu_hotplug(); return; } @@ -3444,8 +3441,6 @@ static void net_dma_rebalance(void) i++; } rcu_read_unlock(); - - unlock_cpu_hotplug(); } /**