Btrfs: Cleanup btrfs_bio_counter_inc_blocked()

1: Remove no-need DEFINE_WAIT(wait)
2: Add likely() for BTRFS_FS_STATE_DEV_REPLACING condition
3: Use while loop instead of goto
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

fs/btrfs/dev-replace.c

@@ -932,15 +932,15 @@ void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)
 
 void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
 {
-	DEFINE_WAIT(wait);
-again:
+	while (1) {
 		percpu_counter_inc(&fs_info->bio_counter);
-	if (test_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state)) {
+		if (likely(!test_bit(BTRFS_FS_STATE_DEV_REPLACING,
+				     &fs_info->fs_state)))
+			break;
+
 		btrfs_bio_counter_dec(fs_info);
 		wait_event(fs_info->replace_wait,
 			   !test_bit(BTRFS_FS_STATE_DEV_REPLACING,
 				     &fs_info->fs_state));
-		goto again;
 	}
-
 }