Staging: xgifb: XGI_main_26.c: Refactored the function

Refactored the function `XGIfb_search_refresh_rate` by removing a level
of `if...else` block nesting. Removed unnecessary parantheses. Removed
potential bug of array underflow.
Signed-off-by: Pratik Jain <pratik.jain0509@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/xgifb/XGI_main_26.c

@@ -544,41 +544,42 @@ static u8 XGIfb_search_refresh_rate(struct xgifb_video_info *xgifb_info,
 	yres = XGIbios_mode[xgifb_info->mode_idx].yres;
 
 	xgifb_info->rate_idx = 0;
-	while ((XGIfb_vrate[i].idx != 0) && (XGIfb_vrate[i].xres <= xres)) {
-		if ((XGIfb_vrate[i].xres == xres) &&
-		    (XGIfb_vrate[i].yres == yres)) {
-			if (XGIfb_vrate[i].refresh == rate) {
+
+	while (XGIfb_vrate[i].idx != 0 && XGIfb_vrate[i].xres <= xres) {
+		/* Skip values with xres or yres less than specified */
+		if ((XGIfb_vrate[i].yres != yres) ||
+		    (XGIfb_vrate[i].xres != xres)) {
+			i++;
+			continue;
+		}
+		if (XGIfb_vrate[i].refresh == rate) {
+			xgifb_info->rate_idx = XGIfb_vrate[i].idx;
+			break;
+		} else if (XGIfb_vrate[i].refresh > rate) {
+			if (XGIfb_vrate[i].refresh - rate <= 3) {
+				pr_debug("Adjusting rate from %d up to %d\n",
+					rate, XGIfb_vrate[i].refresh);
 				xgifb_info->rate_idx = XGIfb_vrate[i].idx;
-				break;
-			} else if (XGIfb_vrate[i].refresh > rate) {
-				if ((XGIfb_vrate[i].refresh - rate) <= 3) {
-					pr_debug("Adjusting rate from %d up to %d\n",
-						 rate, XGIfb_vrate[i].refresh);
-					xgifb_info->rate_idx =
-						XGIfb_vrate[i].idx;
-					xgifb_info->refresh_rate =
-						XGIfb_vrate[i].refresh;
-				} else if (((rate - XGIfb_vrate[i - 1].refresh)
-						<= 2) && (XGIfb_vrate[i].idx
-						!= 1)) {
-					pr_debug("Adjusting rate from %d down to %d\n",
-						 rate,
-						 XGIfb_vrate[i - 1].refresh);
-					xgifb_info->rate_idx =
-						XGIfb_vrate[i - 1].idx;
-					xgifb_info->refresh_rate =
-						XGIfb_vrate[i - 1].refresh;
-				}
-				break;
-			} else if ((rate - XGIfb_vrate[i].refresh) <= 2) {
+				xgifb_info->refresh_rate =
+					XGIfb_vrate[i].refresh;
+			} else if ((XGIfb_vrate[i].idx != 1) &&
+				   (rate - XGIfb_vrate[i - 1].refresh <= 2)) {
 				pr_debug("Adjusting rate from %d down to %d\n",
-					 rate, XGIfb_vrate[i].refresh);
-				xgifb_info->rate_idx = XGIfb_vrate[i].idx;
-				break;
+					rate, XGIfb_vrate[i - 1].refresh);
+				xgifb_info->rate_idx = XGIfb_vrate[i - 1].idx;
+				xgifb_info->refresh_rate =
+					XGIfb_vrate[i - 1].refresh;
 			}
+			break;
+		} else if (rate - XGIfb_vrate[i].refresh <= 2) {
+			pr_debug("Adjusting rate from %d down to %d\n",
+				rate, XGIfb_vrate[i].refresh);
+			xgifb_info->rate_idx = XGIfb_vrate[i].idx;
+			break;
 		}
 		i++;
 	}
+
 	if (xgifb_info->rate_idx > 0)
 		return xgifb_info->rate_idx;
 	pr_info("Unsupported rate %d for %dx%d\n",