ublk: remove "can't touch 'ublk_io' any more" comments

The struct ublk_io is in fact accessed in __ublk_complete_rq() after the
comment. But it's not racy to access the ublk_io between clearing its
UBLK_IO_FLAG_OWNED_BY_SRV flag and completing the request, as no other
thread can use the ublk_io in the meantime.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: calebsander

drivers/block/ublk_drv.c

@@ -3349,7 +3349,6 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd,
 			io_buffer_unregister_bvec(cmd, buf_idx, issue_flags);
 		compl = ublk_need_complete_req(ub, io);
 
-		/* can't touch 'ublk_io' any more */
 		if (req_op(req) == REQ_OP_ZONE_APPEND)
 			req->__sector = addr;
 		if (compl)
@@ -3681,7 +3680,6 @@ static int ublk_batch_commit_io(struct ublk_queue *ubq,
 		return ret;
 	}
 
-	/* can't touch 'ublk_io' any more */
 	if (buf_idx != UBLK_INVALID_BUF_IDX)
 		io_buffer_unregister_bvec(data->cmd, buf_idx, data->issue_flags);
 	if (req_op(req) == REQ_OP_ZONE_APPEND)