ipmi_si: Introduce ipmi_panic_event_str[] array

Instead of repeating twice the constant literals, introduce
ipmi_panic_event_str[] array. It allows to simplify the code
with help of match_string() API.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Message-Id: <20210402174334.13466-6-andriy.shevchenko@linux.intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_msghandler.c

@@ -49,11 +49,17 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
 static bool initialized;
 static bool drvregistered;
 
+/* Numbers in this enumerator should be mapped to ipmi_panic_event_str */
 enum ipmi_panic_event_op {
 	IPMI_SEND_PANIC_EVENT_NONE,
 	IPMI_SEND_PANIC_EVENT,
-	IPMI_SEND_PANIC_EVENT_STRING
+	IPMI_SEND_PANIC_EVENT_STRING,
+	IPMI_SEND_PANIC_EVENT_MAX
 };
+
+/* Indices in this array should be mapped to enum ipmi_panic_event_op */
+static const char *const ipmi_panic_event_str[] = { "none", "event", "string", NULL };
+
 #ifdef CONFIG_IPMI_PANIC_STRING
 #define IPMI_PANIC_DEFAULT IPMI_SEND_PANIC_EVENT_STRING
 #elif defined(CONFIG_IPMI_PANIC_EVENT)
@@ -68,46 +74,27 @@ static int panic_op_write_handler(const char *val,
 				  const struct kernel_param *kp)
 {
 	char valcp[16];
-	char *s;
-
-	strncpy(valcp, val, 15);
-	valcp[15] = '\0';
-
-	s = strstrip(valcp);
+	int e;
 
-	if (strcmp(s, "none") == 0)
-		ipmi_send_panic_event = IPMI_SEND_PANIC_EVENT_NONE;
-	else if (strcmp(s, "event") == 0)
-		ipmi_send_panic_event = IPMI_SEND_PANIC_EVENT;
-	else if (strcmp(s, "string") == 0)
-		ipmi_send_panic_event = IPMI_SEND_PANIC_EVENT_STRING;
-	else
-		return -EINVAL;
+	strscpy(valcp, val, sizeof(valcp));
+	e = match_string(ipmi_panic_event_str, -1, strstrip(valcp));
+	if (e < 0)
+		return e;
 
+	ipmi_send_panic_event = e;
 	return 0;
 }
 
 static int panic_op_read_handler(char *buffer, const struct kernel_param *kp)
 {
-	switch (ipmi_send_panic_event) {
-	case IPMI_SEND_PANIC_EVENT_NONE:
-		strcpy(buffer, "none\n");
-		break;
+	const char *event_str;
 
-	case IPMI_SEND_PANIC_EVENT:
-		strcpy(buffer, "event\n");
-		break;
-
-	case IPMI_SEND_PANIC_EVENT_STRING:
-		strcpy(buffer, "string\n");
-		break;
-
-	default:
-		strcpy(buffer, "???\n");
-		break;
-	}
+	if (ipmi_send_panic_event >= IPMI_SEND_PANIC_EVENT_MAX)
+		event_str = "???";
+	else
+		event_str = ipmi_panic_event_str[ipmi_send_panic_event];
 
-	return strlen(buffer);
+	return sprintf(buffer, "%s\n", event_str);
 }
 
 static const struct kernel_param_ops panic_op_ops = {