md: Binary search in linear raid
Replace the linear search with binary search in which_dev.
Signed-off-by: Sandeep K Sinha <sandeepksinha@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 529a3d3..9b02a73 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -27,14 +27,26 @@
*/
static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector)
{
- dev_info_t *hash;
+ int lo, mid, hi;
linear_conf_t *conf = mddev->private;
- hash = conf->disks;
+ lo = 0;
+ hi = mddev->raid_disks - 1;
- while (sector >= hash->end_sector)
- hash++;
- return hash;
+ /*
+ * Binary Search
+ */
+
+ while (hi > lo) {
+
+ mid = (hi + lo) / 2;
+ if (sector < conf->disks[mid].end_sector)
+ hi = mid;
+ else
+ lo = mid + 1;
+ }
+
+ return conf->disks + lo;
}
/**