[PATCH -next] btrfs: remove set but not used variable 'tree'

[YueHaibing]

Fixes gcc '-Wunused-but-set-variable' warning:

fs/btrfs/extent_io.c: In function 'end_extent_writepage':
fs/btrfs/extent_io.c:2406:25: warning:
 variable 'tree' set but not used [-Wunused-but-set-variable]

It not used any more after
commit 2922040236f9 ("btrfs: Remove extent_io_ops::writepage_end_io_hook")

Signed-off-by: YueHaibing <yuehaib...@huawei.com>
---
 fs/btrfs/extent_io.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0f8f9c0..17a15cc 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2403,11 +2403,8 @@ static int bio_readpage_error(struct bio *failed_bio, 
u64 phy_offset,
 void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
 {
        int uptodate = (err == 0);
-       struct extent_io_tree *tree;
        int ret = 0;
 
-       tree = &BTRFS_I(page->mapping->host)->io_tree;
-
        btrfs_writepage_endio_finish_ordered(page, start, end, NULL, uptodate);
 
        if (!uptodate) {