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this_cpu: Eliminate get/put_cpu

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There are cases where we can use this_cpu_ptr and as the result
of using this_cpu_ptr() we no longer need to determine the
currently executing cpu.

In those places no get/put_cpu combination is needed anymore.
The local cpu variable can be eliminated.

Preemption still needs to be disabled and enabled since the
modifications of the per cpu variables is not atomic. There may
be multiple per cpu variables modified and those must all
be from the same processor.

Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
cc: Eric Biederman <ebiederm@aristanetworks.com>
cc: Stephen Hemminger <shemminger@vyatta.com>
cc: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christoph Lameter
2009-10-03 19:48:23 +09:00
committed by Tejun Heo
parent ca0c9584b1
commit e7dcaa4755
2 changed files with 16 additions and 27 deletions
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7
drivers/net/veth.c
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@@ -153,7 +153,7 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
struct net_device *rcv = NULL;
struct veth_priv *priv, *rcv_priv;
struct veth_net_stats *stats, *rcv_stats;
int length, cpu;
int length;
skb_orphan(skb);
@@ -161,9 +161,8 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
rcv = priv->peer;
rcv_priv = netdev_priv(rcv);
cpu = smp_processor_id();
stats = per_cpu_ptr(priv->stats, cpu);
rcv_stats = per_cpu_ptr(rcv_priv->stats, cpu);
stats = this_cpu_ptr(priv->stats);
rcv_stats = this_cpu_ptr(rcv_priv->stats);
if (!(rcv->flags & IFF_UP))
goto tx_drop;