linux/kernel/range.c
Yinghai Lu 0541881502 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 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>
2013-06-18 11:32:10 -05:00

163 lines
3 KiB
C

/*
* Range add and subtract
*/
#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)
{
if (start >= end)
return nr_range;
/* Out of slots: */
if (nr_range >= az)
return nr_range;
range[nr_range].start = start;
range[nr_range].end = end;
nr_range++;
return nr_range;
}
int add_range_with_merge(struct range *range, int az, int nr_range,
u64 start, u64 end)
{
int i;
if (start >= end)
return nr_range;
/* get new start/end: */
for (i = 0; i < nr_range; i++) {
u64 common_start, common_end;
if (!range[i].end)
continue;
common_start = max(range[i].start, start);
common_end = min(range[i].end, end);
if (common_start > common_end)
continue;
/* new start/end, will add it back at last */
start = min(range[i].start, start);
end = max(range[i].end, 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: */
return add_range(range, az, nr_range, start, end);
}
void subtract_range(struct range *range, int az, u64 start, u64 end)
{
int i, j;
if (start >= end)
return;
for (j = 0; j < az; j++) {
if (!range[j].end)
continue;
if (start <= range[j].start && end >= range[j].end) {
range[j].start = 0;
range[j].end = 0;
continue;
}
if (start <= range[j].start && end < range[j].end &&
range[j].start < end) {
range[j].start = end;
continue;
}
if (start > range[j].start && end >= range[j].end &&
range[j].end > start) {
range[j].end = start;
continue;
}
if (start > range[j].start && end < range[j].end) {
/* Find the new spare: */
for (i = 0; i < az; i++) {
if (range[i].end == 0)
break;
}
if (i < az) {
range[i].end = range[j].end;
range[i].start = end;
} else {
pr_err("%s: run out of slot in ranges\n",
__func__);
}
range[j].end = start;
continue;
}
}
}
static int cmp_range(const void *x1, const void *x2)
{
const struct range *r1 = x1;
const struct range *r2 = x2;
s64 start1, start2;
start1 = r1->start;
start2 = r2->start;
return start1 - start2;
}
int clean_sort_range(struct range *range, int az)
{
int i, j, k = az - 1, nr_range = az;
for (i = 0; i < k; i++) {
if (range[i].end)
continue;
for (j = k; j > i; j--) {
if (range[j].end) {
k = j;
break;
}
}
if (j == i)
break;
range[i].start = range[k].start;
range[i].end = range[k].end;
range[k].start = 0;
range[k].end = 0;
k--;
}
/* count it */
for (i = 0; i < az; i++) {
if (!range[i].end) {
nr_range = i;
break;
}
}
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
return nr_range;
}
void sort_range(struct range *range, int nr_range)
{
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
}