Re: [PATCH v3 4/8] scsi: call scsi_stop_queue() without state_mutex held

Christoph Hellwig
2023-06-08T05:44:56Z

> > Thanks. This wasn't obvious to me from the current code. I'll add a
> > comment in the next version.
>
> The crucial question is now, is it sufficient to call
> blk_mq_quiesce_queue_nowait() under the mutex, or does the call to
> blk_mq_wait_quiesce_done() have to be under the mutex, too?
> The latter would actually kill off our attempt to fix the delay
> in fc_remote_port_delete() that was caused by repeated
> synchronize_rcu() calls.
>
> But if I understand you correctly, moving the wait out of the mutex
> should be ok. I'll update the series accordingly.

I can't think of a reason we'd want to lock over the wait, but Bart
knows this code way better than I do.