Messages in this thread | | | From | Marin Mitov <> | Subject | Is netif_tx_lock() SMP PREEMPT safe? | Date | Fri, 15 Feb 2008 17:25:05 +0200 |
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Hi all,
As in: include/linux/netdevice.h (kernel-2.6.24.2) one finds:
static inline void __netif_tx_lock(struct net_device *dev, int cpu) { spin_lock(&dev->_xmit_lock); dev->xmit_lock_owner = cpu; }
static inline void netif_tx_lock(struct net_device *dev) { __netif_tx_lock(dev, smp_processor_id()); }
Does netif_tx_lock(struct net_device *dev) expands into:
cpu = smp_processor_id(); <preempt & shift to another cpu (bogus)> spin_lock(&dev->_xmit_lock); dev->xmit_lock_owner = cpu; /* cpu is not the lock owner */
Or to:
spin_lock(&dev->_xmit_lock); dev->xmit_lock_owner = smp_processor_id();
which is correct?
Thanks in advance for your answer.
Regards
Marin Mitov
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