From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: IGMP and rwlock: Dead ocurred again on TILEPro
Date: Thu, 17 Feb 2011 14:53:33 -0800 (PST)
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From: Chris Metcalf <cmetcalf@tilera.com>
Date: Thu, 17 Feb 2011 17:49:46 -0500

> The fix is to disable interrupts for the arch_read_lock family of methods. 

How does that help handle the race when it happens between different
cpus, instead of between IRQ and non-IRQ context on the same CPU?

Why don't you just use the generic spinlock based rwlock code on Tile,
since that is all that your atomic instructions can handle
sufficiently?