x86: Move range related operation to one file
We have almost the same code for mtrr cleanup and amd_bus checkup, and
this code will also be used in replacing bootmem with early_res,
so try to move them together and reuse it from different parts.
Also rename update_range to subtract_range as that is what the
function is actually doing.
-v2: update comments as Christoph requested
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-4-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/kernel/range.c b/kernel/range.c
new file mode 100644
index 0000000..71e0021
--- /dev/null
+++ b/kernel/range.c
@@ -0,0 +1,163 @@
+/*
+ * Range add and subtract
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sort.h>
+
+#include <linux/range.h>
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+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;
+
+ /* Try to merge it with old one: */
+ for (i = 0; i < nr_range; i++) {
+ u64 final_start, final_end;
+ 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 + 1)
+ continue;
+
+ final_start = min(range[i].start, start);
+ final_end = max(range[i].end, end);
+
+ range[i].start = final_start;
+ range[i].end = final_end;
+ return nr_range;
+ }
+
+ /* 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 + 1) {
+ range[j].start = end + 1;
+ continue;
+ }
+
+
+ if (start > range[j].start && end >= range[j].end &&
+ range[j].end > start - 1) {
+ range[j].end = start - 1;
+ 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 + 1;
+ } else {
+ printk(KERN_ERR "run of slot in ranges\n");
+ }
+ range[j].end = start - 1;
+ 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 = 0;
+
+ 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);
+}