x86, mtrr: Fix original mtrr range get for mtrr_cleanup
authorYinghai Lu <yinghai@kernel.org>
Thu, 13 Jun 2013 20:17:01 +0000 (13:17 -0700)
committerH. Peter Anvin <hpa@linux.intel.com>
Tue, 18 Jun 2013 16:32:02 +0000 (11:32 -0500)
commitd8d386c10630d8f7837700f4c466443d49e12cc0
tree227534edaf07e34e7613c2847674fb0fd8b6c01a
parent7d132055814ef17a6c7b69f342244c410a5e000f
x86, mtrr: Fix original mtrr range get for mtrr_cleanup

Joshua reported: Commit cd7b304dfaf1 (x86, range: fix missing merge
during add range) broke mtrr cleanup on his setup in 3.9.5.
corresponding commit in upstream is fbe06b7bae7c.

  *BAD*gran_size: 64K chunk_size: 16M num_reg: 6 lose cover RAM: -0G

https://bugzilla.kernel.org/show_bug.cgi?id=59491

So it rejects new var mtrr layout.

It turns out we have some problem with initial mtrr range retrieval.
The current sequence is:
x86_get_mtrr_mem_range
==> bunchs of add_range_with_merge
==> bunchs of subract_range
==> clean_sort_range
add_range_with_merge for [0,1M)
sort_range()

add_range_with_merge could have blank slots, so we can not just
sort only, that will have final result have extra blank slot in head.

So move that calling add_range_with_merge for [0,1M), with that we
could avoid extra clean_sort_range calling.

Reported-by: Joshua Covington <joshuacov@googlemail.com>
Tested-by: Joshua Covington <joshuacov@googlemail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1371154622-8929-2-git-send-email-yinghai@kernel.org
Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
arch/x86/kernel/cpu/mtrr/cleanup.c