netdev - Re: [PATCH 2/9] dma: Convert from tasklet to BH workqueue

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Message-Id: <678ba20b-9f1d-41cb-8a25-e716b61ffafe@app.fastmail.com>
Date: Thu, 28 Mar 2024 20:49:44 +0100
From: "Arnd Bergmann" <arnd@...db.de>
To: Allen <allen.lkml@...il.com>, "Vinod Koul" <vkoul@...nel.org>
Cc: "Allen Pais" <apais@...ux.microsoft.com>, linux-kernel@...r.kernel.org,
 "Tejun Heo" <tj@...nel.org>, "Kees Cook" <keescook@...omium.org>,
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Subject: Re: [PATCH 2/9] dma: Convert from tasklet to BH workqueue

On Thu, Mar 28, 2024, at 20:39, Allen wrote:
>> >
>> > Since almost every driver associates the tasklet with the
>> > dma_chan, we could go one step further and add the
>> > work_queue structure directly into struct dma_chan,
>> > with the wrapper operating on the dma_chan rather than
>> > the work_queue.
>>
>> I think that is very great idea. having this wrapped in dma_chan would
>> be very good way as well
>>
>> Am not sure if Allen is up for it :-)
>
>  Thanks Arnd, I know we did speak about this at LPC. I did start
> working on using completion. I dropped it as I thought it would
> be easier to move to workqueues.

It's definitely easier to do the workqueue conversion as a first
step, and I agree adding support for the completion right away is
probably too much. Moving the work_struct into the dma_chan
is probably not too hard though, if you leave your current
approach for the cases where the tasklet is part of the
dma_dev rather than the dma_chan.

      Arnd