md: replace sysfs api sync_action with new helpers

To get rid of extrem long if else if usage, and make code cleaner.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240611132251.1967786-6-yukuai1@huaweicloud.com

drivers/md/md.c

@@ -4950,27 +4950,9 @@ const char *md_sync_action_name(enum sync_action action)
 static ssize_t
 action_show(struct mddev *mddev, char *page)
 {
-	char *type = "idle";
-	unsigned long recovery = mddev->recovery;
-	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
-		type = "frozen";
-	else if (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
-	    (md_is_rdwr(mddev) && test_bit(MD_RECOVERY_NEEDED, &recovery))) {
-		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
-			type = "reshape";
-		else if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
-			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
-				type = "resync";
-			else if (test_bit(MD_RECOVERY_CHECK, &recovery))
-				type = "check";
-			else
-				type = "repair";
-		} else if (test_bit(MD_RECOVERY_RECOVER, &recovery))
-			type = "recover";
-		else if (mddev->reshape_position != MaxSector)
-			type = "reshape";
-	}
-	return sprintf(page, "%s\n", type);
+	enum sync_action action = md_sync_action(mddev);
+
+	return sprintf(page, "%s\n", md_sync_action_name(action));
 }
 
 /**
@@ -5113,35 +5095,63 @@ static int mddev_start_reshape(struct mddev *mddev)
 static ssize_t
 action_store(struct mddev *mddev, const char *page, size_t len)
 {
+	int ret;
+	enum sync_action action;
+
 	if (!mddev->pers || !mddev->pers->sync_request)
 		return -EINVAL;
 
+	action = md_sync_action_by_name(page);
 
-	if (cmd_match(page, "idle"))
-		idle_sync_thread(mddev);
-	else if (cmd_match(page, "frozen"))
-		frozen_sync_thread(mddev);
-	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
-		return -EBUSY;
-	else if (cmd_match(page, "resync"))
-		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
-	else if (cmd_match(page, "recover")) {
-		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
-		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
-	} else if (cmd_match(page, "reshape")) {
-		int err = mddev_start_reshape(mddev);
-
-		if (err)
-			return err;
+	/* TODO: mdadm rely on "idle" to start sync_thread. */
+	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
+		switch (action) {
+		case ACTION_FROZEN:
+			frozen_sync_thread(mddev);
+			return len;
+		case ACTION_IDLE:
+			idle_sync_thread(mddev);
+			break;
+		case ACTION_RESHAPE:
+		case ACTION_RECOVER:
+		case ACTION_CHECK:
+		case ACTION_REPAIR:
+		case ACTION_RESYNC:
+			return -EBUSY;
+		default:
+			return -EINVAL;
+		}
 	} else {
-		if (cmd_match(page, "check"))
+		switch (action) {
+		case ACTION_FROZEN:
+			set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+			return len;
+		case ACTION_RESHAPE:
+			clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+			ret = mddev_start_reshape(mddev);
+			if (ret)
+				return ret;
+			break;
+		case ACTION_RECOVER:
+			clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
+			break;
+		case ACTION_CHECK:
 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
-		else if (!cmd_match(page, "repair"))
+			fallthrough;
+		case ACTION_REPAIR:
+			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
+			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+			fallthrough;
+		case ACTION_RESYNC:
+		case ACTION_IDLE:
+			clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+			break;
+		default:
 			return -EINVAL;
-		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
-		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
-		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+		}
 	}
+
 	if (mddev->ro == MD_AUTO_READ) {
 		/* A write to sync_action is enough to justify
 		 * canceling read-auto mode