Re: [patch 1/2] net: don't use in_atomic() in gfp_any()

[David Miller <davem@davemloft.net>]

From: akpm@linux-foundation.org
Date: Wed, 11 Feb 2009 13:27:19 -0800

> The problem is that in_atomic() will return false inside spinlocks if
> CONFIG_PREEMPT=n.  This will lead to deadlockable GFP_KERNEL allocations
> from spinlocked regions.
> 
> Secondly, if CONFIG_PREEMPT=y, this bug solves itself because networking
> will instead use GFP_ATOMIC from this callsite.  Hence we won't get the
> might_sleep() debugging warnings which would have informed us of the buggy
> callsites.
> 
> Solve both these problems by switching to in_interrupt().  Now, if someone
> runs a gfp_any() allocation from inside spinlock we will get the warning
> if CONFIG_PREEMPT=y.
> 
> I reviewed all callsites and most of them were too complex for my little
> brain and none of them documented their interface requirements.  I have no
> idea what this patch will do.
> 
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Applied.