1 files changed, 20 insertions, 14 deletions

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 88e4f3ff0cb8..dbfe3e61d2c2 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -183,32 +183,38 @@ static void cec_timer_fn(struct timer_list *unused)
  */
 static int __find_elem(struct ce_array *ca, u64 pfn, unsigned int *to)
 {
+        int min = 0, max = ca->n - 1;
         u64 this_pfn;
-        int min = 0, max = ca->n;
 
-        while (min < max) {
-                int tmp = (max + min) >> 1;
+        while (min <= max) {
+                int i = (min + max) >> 1;
 
-                this_pfn = PFN(ca->array[tmp]);
+                this_pfn = PFN(ca->array[i]);
 
                 if (this_pfn < pfn)
-                        min = tmp + 1;
+                        min = i + 1;
                 else if (this_pfn > pfn)
-                        max = tmp;
-                else {
-                        min = tmp;
-                        break;
+                        max = i - 1;
+                else if (this_pfn == pfn) {
+                        if (to)
+                                *to = i;
+
+                        return i;
                 }
         }
 
+        /*
+         * When the loop terminates without finding @pfn, min has the index of
+         * the element slot where the new @pfn should be inserted. The loop
+         * terminates when min > max, which means the min index points to the
+         * bigger element while the max index to the smaller element, in-between
+         * which the new @pfn belongs to.
+         *
+         * For more details, see exercise 1, Section 6.2.1 in TAOCP, vol. 3.
+         */
         if (to)
                 *to = min;
 
-        this_pfn = PFN(ca->array[min]);
-
-        if (this_pfn == pfn)
-                return min;
-
         return -ENOKEY;
 }