linux-kernel - Re: [PATCH v2] USB: serial: mos7720: defer state restore to a workqueue

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Date:   Wed, 18 Nov 2020 11:11:30 +0100
From:   Johan Hovold <johan@...nel.org>
To:     Davidlohr Bueso <dave@...olabs.net>
Cc:     Johan Hovold <johan@...nel.org>, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, Davidlohr Bueso <dbueso@...e.de>
Subject: Re: [PATCH v2] USB: serial: mos7720: defer state restore to a
 workqueue

On Tue, Nov 17, 2020 at 08:48:37AM -0800, Davidlohr Bueso wrote:
> The parallel port restore operation currently defers writes
> to a tasklet, if it sees a locked disconnect mutex. The
> driver goes to a lot of trouble to ensure writes happen
> in a non-blocking context, but things can be greatly
> simplified if it's done in regular process context and
> this is not a system performance critical path. As such,
> instead of doing the state restore writes in irq context,
> use a workqueue and just do regular synchronous writes.
> 
> In addition to the cleanup, this also imposes less on the
> overall system as tasklets have been deprecated because
> of it's BH implications, potentially blocking a higher
> priority task from running. We also get rid of hacks
> such as trylocking a mutex in irq, something which does

So this was never done in irq either. Perhaps you can remove that bit
too.

> not play nice with priority boosting in PREEMPT_RT.
> 
> Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
> ---
> Changes from v1: remove bogus irq comment.

You seem to have some problem with your mail setup. The patch fails to
apply, and both checkpatch and git warn about the patch being corrupt:

	warning: Patch sent with format=flowed; space at the end of lines might be lost.
	Applying: USB: serial: mos7720: defer state restore to a workqueue
	error: corrupt patch at line 12
	Patch failed at 0001 USB: serial: mos7720: defer state restore to a workqueue

Can you look into that and verify that you can send the patch to
yourself and apply it first?

Johan