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authorDavid S. Miller <davem@davemloft.net>2008-03-27 20:42:50 -0400
committerDavid S. Miller <davem@davemloft.net>2008-03-27 20:42:50 -0400
commit50fd4407b8bfbde7c1a0bfe4f24de7df37164342 (patch)
tree57a9f05b130903fb2c6c12412352928bb24dc3a7 /include
parent8eeee8b152ae6bbe181518efaf62ba8e9c613693 (diff)
[NET]: Use local_irq_{save,restore}() in napi_complete().
Based upon a lockdep report. Since ->poll() can be invoked from netpoll with interrupts disabled, we must not unconditionally enable interrupts in napi_complete(). Instead we must use local_irq_{save,restore}(). Noticed by Peter Zijlstra: <irqs disabled> netpoll_poll() poll_napi() spin_trylock(&napi->poll_lock) poll_one_napi() napi->poll() := sky2_poll() napi_complete() local_irq_disable() local_irq_enable() <--- *BUG* <irq> irq_exit() do_softirq() net_rx_action() spin_lock(&napi->poll_lock) <--- Deadlock! Because we still hold the lock.... Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/netdevice.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a2f003239c85..fae6a7ececdb 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -383,9 +383,11 @@ static inline void __napi_complete(struct napi_struct *n)
383 383
384static inline void napi_complete(struct napi_struct *n) 384static inline void napi_complete(struct napi_struct *n)
385{ 385{
386 local_irq_disable(); 386 unsigned long flags;
387
388 local_irq_save(flags);
387 __napi_complete(n); 389 __napi_complete(n);
388 local_irq_enable(); 390 local_irq_restore(flags);
389} 391}
390 392
391/** 393/**