btrfs: Make btrfs_find_device_by_devspec return btrfs_device directly

Instead of returning an error value and using one of the parameters for
returning the actual object we are interested in just refactor the
function to directly return btrfs_device *. Also bubble up the error
handling for the special BTRFS_ERROR_DEV_MISSING_NOT_FOUND value into
btrfs_rm_device. 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>

fs/btrfs/dev-replace.c

@@ -409,10 +409,10 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 	struct btrfs_device *tgt_device = NULL;
 	struct btrfs_device *src_device = NULL;
 
-	ret = btrfs_find_device_by_devspec(fs_info, srcdevid,
-					    srcdev_name, &src_device);
-	if (ret)
-		return ret;
+	src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
+						  srcdev_name);
+	if (IS_ERR(src_device))
+		return PTR_ERR(src_device);
 
 	ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
 					    src_device, &tgt_device);

fs/btrfs/volumes.c

@@ -1889,10 +1889,16 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
 	if (ret)
 		goto out;
 
-	ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
-					   &device);
-	if (ret)
+	device = btrfs_find_device_by_devspec(fs_info, devid, device_path);
+
+	if (IS_ERR(device)) {
+		if (PTR_ERR(device) == -ENOENT &&
+		    strcmp(device_path, "missing") == 0)
+			ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
+		else
+			ret = PTR_ERR(device);
 		goto out;
+	}
 
 	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
 		ret = BTRFS_ERROR_DEV_TGT_REPLACE;
@@ -2163,30 +2169,21 @@ static struct btrfs_device *btrfs_find_device_missing_or_by_path(
 /*
  * Lookup a device given by device id, or the path if the id is 0.
  */
-int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
-				 const char *devpath,
-				 struct btrfs_device **device)
+struct btrfs_device *btrfs_find_device_by_devspec(
+		struct btrfs_fs_info *fs_info, u64 devid, const char *devpath)
 {
-	int ret = 0;
+	struct btrfs_device *device;
 
 	if (devid) {
-		*device = btrfs_find_device(fs_info, devid, NULL, NULL);
-		if (!*device)
-			ret = -ENOENT;
+		device = btrfs_find_device(fs_info, devid, NULL, NULL);
+		if (!device)
+			return ERR_PTR(-ENOENT);
 	} else {
 		if (!devpath || !devpath[0])
-			return -EINVAL;
-
-		*device = btrfs_find_device_missing_or_by_path(fs_info, devpath);
-		if (IS_ERR(*device)) {
-			if (PTR_ERR(*device) == -ENOENT &&
-			    strcmp(devpath, "missing") == 0)
-				ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
-			else
-				ret = PTR_ERR(*device);
-		}
+			return ERR_PTR(-EINVAL);
+		device = btrfs_find_device_missing_or_by_path(fs_info, devpath);
 	}
-	return ret;
+	return device;
 }
 
 /*

fs/btrfs/volumes.h

@@ -410,9 +410,9 @@ int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
 void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step);
 void btrfs_assign_next_active_device(struct btrfs_device *device,
 				     struct btrfs_device *this_dev);
-int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
-					 const char *devpath,
-					 struct btrfs_device **device);
+struct btrfs_device *btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info,
+						  u64 devid,
+						  const char *devpath);
 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
 					const u64 *devid,
 					const u8 *uuid);