btrfs: open code btrfs_dev_replace_clear_lock_blocking

There's a single caller and the function name does not say it's actually
taking the lock, so open coding makes it more explicit.

For now, btrfs_dev_replace_read_lock is used instead of read_lock so
it's paired with the unlocking wrapper in the same block.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/dev-replace.c

@@ -998,18 +998,6 @@ void btrfs_dev_replace_set_lock_blocking(
 	read_unlock(&dev_replace->lock);
 }
 
-/* acquire read lock and dec blocking cnt */
-void btrfs_dev_replace_clear_lock_blocking(
-					struct btrfs_dev_replace *dev_replace)
-{
-	/* only set blocking for read lock */
-	ASSERT(atomic_read(&dev_replace->blocking_readers) > 0);
-	read_lock(&dev_replace->lock);
-	/* Barrier implied by atomic_dec_and_test */
-	if (atomic_dec_and_test(&dev_replace->blocking_readers))
-		cond_wake_up_nomb(&dev_replace->read_lock_wq);
-}
-
 void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info)
 {
 	percpu_counter_inc(&fs_info->bio_counter);

fs/btrfs/dev-replace.h

@@ -28,8 +28,6 @@ void btrfs_dev_replace_read_unlock(struct btrfs_dev_replace *dev_replace);
 void btrfs_dev_replace_write_lock(struct btrfs_dev_replace *dev_replace);
 void btrfs_dev_replace_write_unlock(struct btrfs_dev_replace *dev_replace);
 void btrfs_dev_replace_set_lock_blocking(struct btrfs_dev_replace *dev_replace);
-void btrfs_dev_replace_clear_lock_blocking(
-					struct btrfs_dev_replace *dev_replace);
 
 static inline void btrfs_dev_replace_stats_inc(atomic64_t *stat_value)
 {

fs/btrfs/volumes.c

@@ -5904,7 +5904,11 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 	}
 out:
 	if (dev_replace_is_ongoing) {
-		btrfs_dev_replace_clear_lock_blocking(dev_replace);
+		ASSERT(atomic_read(&dev_replace->blocking_readers) > 0);
+		btrfs_dev_replace_read_lock(dev_replace);
+		/* Barrier implied by atomic_dec_and_test */
+		if (atomic_dec_and_test(&dev_replace->blocking_readers))
+			cond_wake_up_nomb(&dev_replace->read_lock_wq);
 		btrfs_dev_replace_read_unlock(dev_replace);
 	}
 	free_extent_map(em);