btrfs: Remove extent_io_ops::split_extent_hook callback

This is the counterpart to merge_extent_hook, similarly, it's used only
for data/freespace inodes so let's remove it, rename it and call it
directly where necessary. No functional changes.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -3156,6 +3156,8 @@ void btrfs_clear_delalloc_extent(struct inode *inode,
 				 struct extent_state *state, unsigned *bits);
 void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
 				 struct extent_state *other);
+void btrfs_split_delalloc_extent(struct inode *inode,
+				 struct extent_state *orig, u64 split);
 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
 			 size_t size, struct bio *bio,
 			 unsigned long bio_flags);

fs/btrfs/extent_io.c

@@ -445,13 +445,6 @@ static int insert_state(struct extent_io_tree *tree,
 	return 0;
 }
 
-static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
-		     u64 split)
-{
-	if (tree->ops && tree->ops->split_extent_hook)
-		tree->ops->split_extent_hook(tree->private_data, orig, split);
-}
-
 /*
  * split a given extent state struct in two, inserting the preallocated
  * struct 'prealloc' as the newly created second half.  'split' indicates an
@@ -471,7 +464,8 @@ static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 {
 	struct rb_node *node;
 
-	split_cb(tree, orig, split);
+	if (tree->private_data && is_data_inode(tree->private_data))
+		btrfs_split_delalloc_extent(tree->private_data, orig, split);
 
 	prealloc->start = orig->start;
 	prealloc->end = split - 1;

fs/btrfs/extent_io.h

@@ -102,12 +102,6 @@ struct extent_io_ops {
 				    struct page *page, u64 start, u64 end,
 				    int mirror);
 	int (*readpage_io_failed_hook)(struct page *page, int failed_mirror);
-
-	/*
-	 * Optional hooks, called if the pointer is not NULL
-	 */
-	void (*split_extent_hook)(void *private_data,
-				  struct extent_state *orig, u64 split);
 };
 
 struct extent_io_tree {

fs/btrfs/inode.c

@@ -1609,10 +1609,9 @@ int btrfs_run_delalloc_range(void *private_data, struct page *locked_page,
 	return ret;
 }
 
-static void btrfs_split_extent_hook(void *private_data,
+void btrfs_split_delalloc_extent(struct inode *inode,
 				 struct extent_state *orig, u64 split)
 {
-	struct inode *inode = private_data;
 	u64 size;
 
 	/* not delalloc, ignore it */
@@ -10504,9 +10503,6 @@ static const struct extent_io_ops btrfs_extent_io_ops = {
 	.submit_bio_hook = btrfs_submit_bio_hook,
 	.readpage_end_io_hook = btrfs_readpage_end_io_hook,
 	.readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
-
-	/* optional callbacks */
-	.split_extent_hook = btrfs_split_extent_hook,
 };
 
 /*