From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>, netdev@vger.kernel.org
Subject: netif_poll_enable() & barrier
Date: Wed, 20 Dec 2006 14:44:12 +1100 [thread overview]
Message-ID: <1166586252.19254.118.camel@localhost.localdomain> (raw)
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.
next reply other threads:[~2006-12-20 3:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-20 3:44 Benjamin Herrenschmidt [this message]
2006-12-29 5:09 ` netif_poll_enable() & barrier David Miller
2006-12-29 5:45 ` Benjamin Herrenschmidt
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