btrfs: drop num argument from find_live_mirror()

Obtain the stripes info from the map directly and so no need
to pass it as an argument.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -5274,13 +5274,22 @@ int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 }
 
 static int find_live_mirror(struct btrfs_fs_info *fs_info,
-			    struct map_lookup *map, int first, int num,
+			    struct map_lookup *map, int first,
 			    int optimal, int dev_replace_is_ongoing)
 {
 	int i;
+	int num_stripes;
 	int tolerance;
 	struct btrfs_device *srcdev;
 
+	ASSERT((map->type &
+		 (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)));
+
+	if (map->type & BTRFS_BLOCK_GROUP_RAID10)
+		num_stripes = map->sub_stripes;
+	else
+		num_stripes = map->num_stripes;
+
 	if (dev_replace_is_ongoing &&
 	    fs_info->dev_replace.cont_reading_from_srcdev_mode ==
 	     BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
@@ -5297,7 +5306,7 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info,
 		if (map->stripes[optimal].dev->bdev &&
 		    (tolerance || map->stripes[optimal].dev != srcdev))
 			return optimal;
-		for (i = first; i < first + num; i++) {
+		for (i = first; i < first + num_stripes; i++) {
 			if (map->stripes[i].dev->bdev &&
 			    (tolerance || map->stripes[i].dev != srcdev))
 				return i;
@@ -5834,7 +5843,6 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 			stripe_index = mirror_num - 1;
 		else {
 			stripe_index = find_live_mirror(fs_info, map, 0,
-					    map->num_stripes,
 					    current->pid % map->num_stripes,
 					    dev_replace_is_ongoing);
 			mirror_num = stripe_index + 1;
@@ -5863,7 +5871,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 			int old_stripe_index = stripe_index;
 			stripe_index = find_live_mirror(fs_info, map,
 					      stripe_index,
-					      map->sub_stripes, stripe_index +
+					      stripe_index +
 					      current->pid % map->sub_stripes,
 					      dev_replace_is_ongoing);
 			mirror_num = stripe_index - old_stripe_index + 1;