Messages in this thread | | | Date | Mon, 16 Nov 2020 14:31:02 -0800 | From | Davidlohr Bueso <> | Subject | Re: [PATCH] USB: serial: mos7720: defer state restore to a workqueue |
| |
On Mon, 16 Nov 2020, Johan Hovold wrote:
>On Fri, Nov 13, 2020 at 08:27:25PM -0800, Davidlohr Bueso wrote: >> @@ -1883,21 +1724,17 @@ static void mos7720_release(struct usb_serial *serial) >> if (mos_parport->msg_pending) >> wait_for_completion_timeout(&mos_parport->syncmsg_compl, >> msecs_to_jiffies(MOS_WDR_TIMEOUT)); >> + /* >> + * If delayed work is currently scheduled, wait for it to >> + * complete. This also implies barriers that ensure the >> + * below serial clearing is not hoisted above the ->work. >> + */ >> + cancel_work_sync(&mos_parport->work); > >As I mentioned, this needs to be done *after* deregistering the port or >you could theoretically end up with the work item being requeued.
Hmm sorry yes I forgot to mention this. I was counting on the private_data already being null to prevent any new work being actually scheduled, so an incoming restore state, for example, would be a nop.
> >Yes, the same applies for the "synchronous" requests, but that's a >preexisting issue.
Per the above I also assumed sync requests were also safe as is.
But I can certainly re-order things, how about:
mos7720_release(): mos_parport->pp->private_data = NULL; parport_remove_port(mos_parport->pp);
wait_for_completion_timeout(); cancel_work_sync();
usb_set_serial_data(serial, NULL); mos_parport->serial = NULL;
parport_del_port(mos_parport->pp); kref_put();
Thanks, Davidlohr
| |