Re: [PATCH v14 1/4] usb: Add support for Intel LJCA device

[Oliver Neukum <oneukum@suse.com>]

On 05.09.23 04:20, Wu, Wentong wrote:

Hi,

>> That is that you will hang arbitrarily long in disconnect?
> This routine isn't called in an interrupt context, and it allows sleep or wait
> something before the real shutdown like many drivers' remove() or
> disconnect() do.

It is, however, in the context of a kernel thread. We can wait, but not for
arbitrary periods.

> If we want to speed up the disconnect(), below changes is to complete the
> cmd_completion if usb_kill_urb() has been called, but there is still possibility
> ljca client init one more transfer before auxiliary_device_delete()
> 
> @@ -206,7 +206,11 @@ static void ljca_recv(struct urb *urb)
>   
>          if (urb->status) {
>                  /* sync/async unlink faults aren't errors */
> -               if (urb->status == -ENOENT || urb->status == -ECONNRESET ||
> +               if (urb->status == -ENOENT) {
> +                       complete(&adap->cmd_completion);
> +                       return;

I'd say you'd break suspend() by such a change.
You cannot complete in the interrupt handler, unless you can determine
why the URB is killed.
  
> +               }
> +               if (urb->status == -ECONNRESET ||
>                      urb->status == -ESHUTDOWN)
>                          return;
> 
> perhaps we could add one more 'status' field in ljca_adapter to represent
> disconnect() happen or not, and it will be checked in the beginning of
> ljca_send() to avoid any new transfer.

That would be a solution.


	Regards
		Oliver