btrfs: Remove unused arguments from btrfs_changed_cb_t

btrfs_changed_cb_t represents the signature of the callback being passed
to btrfs_compare_trees. Currently there is only one such callback,
namely changed_cb in send.c. This function doesn't really uses the first
2 parameters, i.e. the roots. Since there are not other functions
implementing the btrfs_changed_cb_t let's remove the unused parameters
from the prototype and implementation.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.c

@@ -5496,8 +5496,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
 			goto out;
 		} else if (left_end_reached) {
 			if (right_level == 0) {
-				ret = changed_cb(left_root, right_root,
-						left_path, right_path,
+				ret = changed_cb(left_path, right_path,
 						&right_key,
 						BTRFS_COMPARE_TREE_DELETED,
 						ctx);
@@ -5508,8 +5507,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
 			continue;
 		} else if (right_end_reached) {
 			if (left_level == 0) {
-				ret = changed_cb(left_root, right_root,
-						left_path, right_path,
+				ret = changed_cb(left_path, right_path,
 						&left_key,
 						BTRFS_COMPARE_TREE_NEW,
 						ctx);
@@ -5523,8 +5521,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
 		if (left_level == 0 && right_level == 0) {
 			cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
 			if (cmp < 0) {
-				ret = changed_cb(left_root, right_root,
-						left_path, right_path,
+				ret = changed_cb(left_path, right_path,
 						&left_key,
 						BTRFS_COMPARE_TREE_NEW,
 						ctx);
@@ -5532,8 +5529,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
 					goto out;
 				advance_left = ADVANCE;
 			} else if (cmp > 0) {
-				ret = changed_cb(left_root, right_root,
-						left_path, right_path,
+				ret = changed_cb(left_path, right_path,
 						&right_key,
 						BTRFS_COMPARE_TREE_DELETED,
 						ctx);
@@ -5550,8 +5546,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
 					result = BTRFS_COMPARE_TREE_CHANGED;
 				else
 					result = BTRFS_COMPARE_TREE_SAME;
-				ret = changed_cb(left_root, right_root,
-						 left_path, right_path,
+				ret = changed_cb(left_path, right_path,
 						 &left_key, result, ctx);
 				if (ret < 0)
 					goto out;

fs/btrfs/ctree.h

@@ -2821,9 +2821,7 @@ enum btrfs_compare_tree_result {
 	BTRFS_COMPARE_TREE_CHANGED,
 	BTRFS_COMPARE_TREE_SAME,
 };
-typedef int (*btrfs_changed_cb_t)(struct btrfs_root *left_root,
-				  struct btrfs_root *right_root,
-				  struct btrfs_path *left_path,
+typedef int (*btrfs_changed_cb_t)(struct btrfs_path *left_path,
 				  struct btrfs_path *right_path,
 				  struct btrfs_key *key,
 				  enum btrfs_compare_tree_result result,

fs/btrfs/send.c

@@ -6159,9 +6159,7 @@ out:
  * Updates compare related fields in sctx and simply forwards to the actual
  * changed_xxx functions.
  */
-static int changed_cb(struct btrfs_root *left_root,
-		      struct btrfs_root *right_root,
-		      struct btrfs_path *left_path,
+static int changed_cb(struct btrfs_path *left_path,
 		      struct btrfs_path *right_path,
 		      struct btrfs_key *key,
 		      enum btrfs_compare_tree_result result,
@@ -6243,8 +6241,8 @@ static int full_send_tree(struct send_ctx *sctx)
 		slot = path->slots[0];
 		btrfs_item_key_to_cpu(eb, &found_key, slot);
 
-		ret = changed_cb(send_root, NULL, path, NULL,
-				&found_key, BTRFS_COMPARE_TREE_NEW, sctx);
+		ret = changed_cb(path, NULL, &found_key,
+				 BTRFS_COMPARE_TREE_NEW, sctx);
 		if (ret < 0)
 			goto out;