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range: Do not add new blank slot with add_range_with_merge

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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 fbe06b7bae.

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: 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/1371154622-8929-3-git-send-email-yinghai@kernel.org
Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Yinghai Lu 2013-06-13 13:17:02 -07:00 committed by H. Peter Anvin
parent d8d386c106
commit 0541881502
1 changed files with 11 additions and 10 deletions
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21
kernel/range.c
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@ -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: */