rdmacg: Convert to use match_string() helper

The new helper returns index of the matching string in an array.
We are going to use it here.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/cgroup/rdma.c b/kernel/cgroup/rdma.c
index defad3c..d3bbb75 100644
--- a/kernel/cgroup/rdma.c
+++ b/kernel/cgroup/rdma.c
@@ -362,35 +362,32 @@ EXPORT_SYMBOL(rdmacg_unregister_device);
 static int parse_resource(char *c, int *intval)
 {
 	substring_t argstr;
-	const char **table = &rdmacg_resource_names[0];
 	char *name, *value = c;
 	size_t len;
-	int ret, i = 0;
+	int ret, i;
 
 	name = strsep(&value, "=");
 	if (!name || !value)
 		return -EINVAL;
 
+	i = match_string(rdmacg_resource_names, RDMACG_RESOURCE_MAX, name);
+	if (i < 0)
+		return i;
+
 	len = strlen(value);
 
-	for (i = 0; i < RDMACG_RESOURCE_MAX; i++) {
-		if (strcmp(table[i], name))
-			continue;
+	argstr.from = value;
+	argstr.to = value + len;
 
-		argstr.from = value;
-		argstr.to = value + len;
-
-		ret = match_int(&argstr, intval);
-		if (ret >= 0) {
-			if (*intval < 0)
-				break;
-			return i;
-		}
-		if (strncmp(value, RDMACG_MAX_STR, len) == 0) {
-			*intval = S32_MAX;
-			return i;
-		}
-		break;
+	ret = match_int(&argstr, intval);
+	if (ret >= 0) {
+		if (*intval < 0)
+			return -EINVAL;
+		return i;
+	}
+	if (strncmp(value, RDMACG_MAX_STR, len) == 0) {
+		*intval = S32_MAX;
+		return i;
 	}
 	return -EINVAL;
 }