From: Andrew Morton <akpm@linux-foundation.org>
Date: Tue, 11 Sep 2007 22:24:10 +0000 (-0700)
Subject: revert "highmem: catch illegal nesting"
X-Git-Tag: v2.6.23-rc7~71
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4150d3f549fe2355625017b2a6ff72aec98bcef0;p=pandora-kernel.git

revert "highmem: catch illegal nesting"

Revert

	commit 656dad312fb41ed95ef08325e9df9bece3aacbbb
	Author: Ingo Molnar <mingo@elte.hu>
	Date:   Sat Feb 10 01:46:36 2007 -0800

	[PATCH] highmem: catch illegal nesting

	Catch illegally nested kmap_atomic()s even if the page that is mapped by
	the 'inner' instance is from lowmem.

	This avoids spuriously zapped kmap-atomic ptes and turns hard to find
	crashes into clear asserts at the bug site.

Problem is, a get_zeroed_page(GFP_KERNEL) from interrupt context will trigger
this check if non-irq code on this CPU holds a KM_USER0 mapping.  But that
get_zeroed_page() will never be altering the kmap slot anyway due to the
GFP_KERNEL.

Cc: Christoph Lameter <clameter@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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