btrfs: Make btrfs_find_device_by_path return struct btrfs_device

Currently this function returns an error code as well as uses one of
its arguments as a return value for struct btrfs_device. Change the
function so that it returns btrfs_device directly and use the usual
"encode error in pointer" mechanics if something goes wrong. No
functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ea9845a5e6012b71893ae35d1a03cd0ec4838bee..3e21e07d3f0337ec8a6cfee945ca3a57bdb19ee4 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2108,9 +2108,8 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev)
        call_rcu(&tgtdev->rcu, free_device_rcu);
 }
 
-static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
-                                    const char *device_path,
-                                    struct btrfs_device **device)
+static struct btrfs_device *btrfs_find_device_by_path(
+               struct btrfs_fs_info *fs_info, const char *device_path)
 {
        int ret = 0;
        struct btrfs_super_block *disk_super;
@@ -2118,21 +2117,21 @@ static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
        u8 *dev_uuid;
        struct block_device *bdev;
        struct buffer_head *bh;
+       struct btrfs_device *device;
 
-       *device = NULL;
        ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
                                    fs_info->bdev_holder, 0, &bdev, &bh);
        if (ret)
-               return ret;
+               return ERR_PTR(ret);
        disk_super = (struct btrfs_super_block *)bh->b_data;
        devid = btrfs_stack_device_id(&disk_super->dev_item);
        dev_uuid = disk_super->dev_item.uuid;
-       *device = btrfs_find_device(fs_info, devid, dev_uuid, disk_super->fsid);
+       device = btrfs_find_device(fs_info, devid, dev_uuid, disk_super->fsid);
        brelse(bh);
-       if (!*device)
-               ret = -ENOENT;
+       if (!device)
+               device = ERR_PTR(-ENOENT);
        blkdev_put(bdev, FMODE_READ);
-       return ret;
+       return device;
 }
 
 int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
@@ -2155,11 +2154,13 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
 
                if (!*device)
                        return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
-
-               return 0;
        } else {
-               return btrfs_find_device_by_path(fs_info, device_path, device);
+               *device = btrfs_find_device_by_path(fs_info, device_path);
+               if (IS_ERR(*device))
+                       return PTR_ERR(*device);
        }
+
+       return 0;
 }
 
 /*