* netif_poll_enable() & barrier
@ 2006-12-20 3:44 Benjamin Herrenschmidt
0 siblings, 0 replies; only message in thread
From: Benjamin Herrenschmidt @ 2006-12-20 3:44 UTC (permalink / raw)
To: David S. Miller; +Cc: Linux Kernel list, netdev
Hi !
I stumbled accross what might be a bug on out of order architecture:
netif_poll_enable() only does a clear_bit(). However,
netif_poll_disable/enable pairs are often used as simili-spinlocks.
(netif_poll_enable() has pretty much spin_lock semantics except that it
schedules instead of looping).
Thus, shouldn't netif_poll_disable() do an smp_wmb(); before clearing
the bit to make sure that any stores done within the poll-disabled
section are properly visible to the rest of the system before clearing
the bit ?
Cheers,
Ben.
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