ext4: remove buffer_uninit handling

There isn't any need for setting BH_Uninit on buffers anymore.  It was
only used to signal we need to mark io_end as needing extent
conversion in add_bh_to_extent() but now we can mark the io_end
directly when mapping extent.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 90a164f..0a9b729 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2653,20 +2653,17 @@
 extern int ext4_mmp_csum_verify(struct super_block *sb,
 				struct mmp_struct *mmp);
 
-/* BH_Uninit flag: blocks are allocated but uninitialized on disk */
+/*
+ * Note that these flags will never ever appear in a buffer_head's state flag.
+ * See EXT4_MAP_... to see where this is used.
+ */
 enum ext4_state_bits {
 	BH_Uninit	/* blocks are allocated but uninitialized on disk */
-	  = BH_JBDPrivateStart,
+	 = BH_JBDPrivateStart,
 	BH_AllocFromCluster,	/* allocated blocks were part of already
-				 * allocated cluster. Note that this flag will
-				 * never, ever appear in a buffer_head's state
-				 * flag. See EXT4_MAP_FROM_CLUSTER to see where
-				 * this is used. */
+				 * allocated cluster. */
 };
 
-BUFFER_FNS(Uninit, uninit)
-TAS_BUFFER_FNS(Uninit, uninit)
-
 /*
  * Add new method to test whether block and inode bitmaps are properly
  * initialized. With uninit_bg reading the block from disk is not enough