Re: [PATCH] Address USB abort races

[Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost>]

> Date: Mon, 23 Dec 2019 14:17:18 +0000
> From: Nick Hudson <nick.hudson%gmx.co.uk@localhost>
> 
> - Any reason that dwc2 and ahci didn't get the conversion? At least dwc2
>    should be done - I'm not sure ahci ever worked, but I've tried to keep
>    it up-to-date in the past.  slhci probably needs some love too.

I forgot to check it.  I searched for *hci but dwc2 doesn't match that
pattern!

> - It appears to me that upm_abort could be removed in favour of
>    ubm_abortx and all the xfer cancel logic contained there, but that
>    could be a future change

Root intr transfer handling doesn't go through the same path.  Perhaps
it could; perhaps that would be simpler.

> - Off list you mentioned ohci getting stuck during testing and I would
>    agree it's unlikely that these diffs caused the issue.  I have some
>    changes to ohci aborting on nhusb which I'll try and fixup when this
>    diff goes in.

Based on some tests I did shortly before leaving for the weekend, I
realized it might be a mistake in the root intr transfer handling.
Will investigate further.