btrfs: sink extent_write_locked_range tree parameter

This function is called only from submit_compressed_extents and the
io tree being passed is always that of the inode. But we are also
passing the inode, so just move getting the io tree pointer in
extent_write_locked_range to simplify the signature.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 16ae832..c0b2bf6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4073,11 +4073,12 @@ int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
 	return ret;
 }
 
-int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
-			      u64 start, u64 end, int mode)
+int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
+			      int mode)
 {
 	int ret = 0;
 	struct address_space *mapping = inode->i_mapping;
+	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 	struct page *page;
 	unsigned long nr_pages = (end - start + PAGE_SIZE) >>
 		PAGE_SHIFT;