DM RAID: Move 'rebuild' checking code to its own function

DM RAID:  Move chunk of code to it's own function

The code that checks whether device replacements/rebuilds are possible given
a specific RAID type is moved to it's own function.  It will further expand
when the code to check RAID10 is added.  A separate function makes it easier
to read.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/dm-raid.c

@@ -337,6 +337,52 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 	return 0;
 }
 
+/*
+ * validate_rebuild_devices
+ * @rs
+ *
+ * Determine if the devices specified for rebuild can result in a valid
+ * usable array that is capable of rebuilding the given devices.
+ *
+ * Returns: 0 on success, -EINVAL on failure.
+ */
+static int validate_rebuild_devices(struct raid_set *rs)
+{
+	unsigned i, rebuild_cnt = 0;
+
+	if (!(rs->print_flags & DMPF_REBUILD))
+		return 0;
+
+	for (i = 0; i < rs->md.raid_disks; i++)
+		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
+			rebuild_cnt++;
+
+	switch (rs->raid_type->level) {
+	case 1:
+		if (rebuild_cnt >= rs->md.raid_disks)
+			goto too_many;
+		break;
+	case 4:
+	case 5:
+	case 6:
+		if (rebuild_cnt > rs->raid_type->parity_devs)
+			goto too_many;
+		break;
+	case 10:
+	default:
+		DMERR("The rebuild parameter is not supported for %s",
+		      rs->raid_type->name);
+		rs->ti->error = "Rebuild not supported for this RAID type";
+		return -EINVAL;
+	}
+
+	return 0;
+
+too_many:
+	rs->ti->error = "Too many rebuild devices specified";
+	return -EINVAL;
+}
+
 /*
  * Possible arguments are...
  *	<chunk_size> [optional_args]
@@ -365,7 +411,7 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
 {
 	char *raid10_format = "near";
 	unsigned raid10_copies = 2;
-	unsigned i, rebuild_cnt = 0;
+	unsigned i;
 	unsigned long value, region_size = 0;
 	sector_t sectors_per_dev = rs->ti->len;
 	sector_t max_io_len;
@@ -461,30 +507,6 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
 
 		/* Parameters that take a numeric value are checked here */
 		if (!strcasecmp(key, "rebuild")) {
-			rebuild_cnt++;
-
-			switch (rs->raid_type->level) {
-			case 1:
-				if (rebuild_cnt >= rs->md.raid_disks) {
-					rs->ti->error = "Too many rebuild devices specified";
-					return -EINVAL;
-				}
-				break;
-			case 4:
-			case 5:
-			case 6:
-				if (rebuild_cnt > rs->raid_type->parity_devs) {
-					rs->ti->error = "Too many rebuild devices specified for given RAID type";
-					return -EINVAL;
-				}
-				break;
-			case 10:
-			default:
-				DMERR("The rebuild parameter is not supported for %s", rs->raid_type->name);
-				rs->ti->error = "Rebuild not supported for this RAID type";
-				return -EINVAL;
-			}
-
 			if (value > rs->md.raid_disks) {
 				rs->ti->error = "Invalid rebuild index given";
 				return -EINVAL;
@@ -608,6 +630,9 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
 	}
 	rs->md.dev_sectors = sectors_per_dev;
 
+	if (validate_rebuild_devices(rs))
+		return -EINVAL;
+
 	/* Assume there are no metadata devices until the drives are parsed */
 	rs->md.persistent = 0;
 	rs->md.external = 1;