block: remove the blk_flush_integrity call in blk_integrity_unregister

Now that there are no indirect calls for PI processing there is no
way to dereference a NULL pointer here.  Additionally drivers now always
freeze the queue (or in case of stacking drivers use their internal
equivalent) around changing the integrity profile.

This is effectively a revert of commit 3df4996 ("block: flush the
integrity workqueue in blk_integrity_unregister").

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Christoph Hellwig

block/blk-integrity.c

@@ -401,8 +401,6 @@ void blk_integrity_unregister(struct gendisk *disk)
 	if (!bi->tuple_size)
 		return;
 
-	/* ensure all bios are off the integrity workqueue */
-	blk_flush_integrity();
 	blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, disk->queue);
 	memset(bi, 0, sizeof(*bi));
 }