btrfs: Remove 'tree' argument from read_extent_buffer_pages

This function always uses the btree inode's io_tree. Stop taking the
tree as a function argument and instead access it internally from
read_extent_buffer_pages. No functional changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
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/disk-io.c

@@ -465,8 +465,7 @@ static int btree_read_extent_buffer_pages(struct extent_buffer *eb,
 	io_tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
 	while (1) {
 		clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
-		ret = read_extent_buffer_pages(io_tree, eb, WAIT_COMPLETE,
-					       mirror_num);
+		ret = read_extent_buffer_pages(eb, WAIT_COMPLETE, mirror_num);
 		if (!ret) {
 			if (verify_parent_transid(io_tree, eb,
 						   parent_transid, 0))
@@ -1034,15 +1033,13 @@ static const struct address_space_operations btree_aops = {
 void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr)
 {
 	struct extent_buffer *buf = NULL;
-	struct inode *btree_inode = fs_info->btree_inode;
 	int ret;
 
 	buf = btrfs_find_create_tree_block(fs_info, bytenr);
 	if (IS_ERR(buf))
 		return;
 
-	ret = read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf,
-			WAIT_NONE, 0);
+	ret = read_extent_buffer_pages(buf, WAIT_NONE, 0);
 	if (ret < 0)
 		free_extent_buffer_stale(buf);
 	else
@@ -1053,8 +1050,6 @@ int reada_tree_block_flagged(struct btrfs_fs_info *fs_info, u64 bytenr,
 			 int mirror_num, struct extent_buffer **eb)
 {
 	struct extent_buffer *buf = NULL;
-	struct inode *btree_inode = fs_info->btree_inode;
-	struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
 	int ret;
 
 	buf = btrfs_find_create_tree_block(fs_info, bytenr);
@@ -1063,8 +1058,7 @@ int reada_tree_block_flagged(struct btrfs_fs_info *fs_info, u64 bytenr,
 
 	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
 
-	ret = read_extent_buffer_pages(io_tree, buf, WAIT_PAGE_LOCK,
-				       mirror_num);
+	ret = read_extent_buffer_pages(buf, WAIT_PAGE_LOCK, mirror_num);
 	if (ret) {
 		free_extent_buffer_stale(buf);
 		return ret;

fs/btrfs/extent_io.c

@@ -5330,8 +5330,7 @@ void set_extent_buffer_uptodate(struct extent_buffer *eb)
 	}
 }
 
-int read_extent_buffer_pages(struct extent_io_tree *tree,
-			     struct extent_buffer *eb, int wait, int mirror_num)
+int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num)
 {
 	int i;
 	struct page *page;
@@ -5343,6 +5342,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	unsigned long num_reads = 0;
 	struct bio *bio = NULL;
 	unsigned long bio_flags = 0;
+	struct extent_io_tree *tree = &BTRFS_I(eb->fs_info->btree_inode)->io_tree;
 
 	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
 		return 0;

fs/btrfs/extent_io.h

@@ -433,8 +433,7 @@ void free_extent_buffer_stale(struct extent_buffer *eb);
 #define WAIT_NONE	0
 #define WAIT_COMPLETE	1
 #define WAIT_PAGE_LOCK	2
-int read_extent_buffer_pages(struct extent_io_tree *tree,
-			     struct extent_buffer *eb, int wait,
+int read_extent_buffer_pages(struct extent_buffer *eb, int wait,
 			     int mirror_num);
 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);