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Commit 05418815 authored by Yinghai Lu's avatar Yinghai Lu Committed by H. Peter Anvin
Browse files

range: Do not add new blank slot with add_range_with_merge 



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 fbe06b7b.

The reason is add_range_with_merge could generate blank spot.

We could avoid that by searching new expanded start/end, that
new range should include all connected ranges in range array.
At last add the new expanded start/end to the range array.
Also move up left array so do not add new blank slot in the
range array.

-v2: move left array to avoid enhance add_range()
-v3: include fix from Joshua about memmove declaring when
     DYN_DEBUG is used.

Reported-by: default avatarJoshua Covington <joshuacov@googlemail.com>
Tested-by: default avatarJoshua Covington <joshuacov@googlemail.com>
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1371154622-8929-3-git-send-email-yinghai@kernel.org


Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent d8d386c1

kernel/range.c

+11 −10
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 
#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/sort.h>



#include <linux/string.h>

#include <linux/range.h>



int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
@@ -32,9 +32,8 @@ int add_range_with_merge(struct range *range, int az, int nr_range, 
	if (start >= end)

		return nr_range;



	/* Try to merge it with old one: */

	/* get new start/end: */

	for (i = 0; i < nr_range; i++) {

		u64 final_start, final_end;

		u64 common_start, common_end;



		if (!range[i].end)
@@ -45,14 +44,16 @@ int add_range_with_merge(struct range *range, int az, int nr_range, 
		if (common_start > common_end)

			continue;



		final_start = min(range[i].start, start);

		final_end = max(range[i].end, end);

		/* new start/end, will add it back at last */

		start = min(range[i].start, start);

		end = max(range[i].end, end);



		/* clear it and add it back for further merge */

		range[i].start = 0;

		range[i].end =  0;

		return add_range_with_merge(range, az, nr_range,

			final_start, final_end);

		memmove(&range[i], &range[i + 1],

			(nr_range - (i + 1)) * sizeof(range[i]));

		range[nr_range - 1].start = 0;

		range[nr_range - 1].end   = 0;

		nr_range--;

		i--;

	}



	/* Need to add it: */