Re: [PATCH v2 08/13] dmaengine: at_xdmac: Move the free desc to the tail of the desc list

From: Vinod Koul
Date: Mon Dec 13 2021 - 04:01:04 EST


On 13-12-21, 14:29, Vinod Koul wrote:
> On 13-12-21, 08:51, Tudor.Ambarus@xxxxxxxxxxxxx wrote:
> > Hi, Vinod,
> >
> > On 12/13/21 10:07 AM, Vinod Koul wrote:
> > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> > >
> > > On 25-11-21, 11:00, Tudor Ambarus wrote:
> > >> So that we don't use the same desc over and over again.
> > >
> > > Please use full para in the changelog and not a continuation of the
> > > patch title!
> >
> > Ok, will add a better commit description. Here and in other patches where
> > your comment applies.
>
> Great!
>
> > >
> > > and why is wrong with using same desc over and over? Any benefits of not
> > > doing so?
> >
> > Not wrong, but if we move the free desc to the tail of the list, then the
> > sequence of descriptors is more track-able in case of debug. You would
> > know which descriptor should come next and you could easier catch
> > concurrency over descriptors for example. I saw virt-dma uses
> > list_splice_tail_init() as well, I found it a good idea, so I thought to
> > follow the core driver.
>
> Okay, I would be good to add this motivation in the change log. I am
> sure after few you would also wonder why you did this change :)

Also, pls submit serial patches to Greg separately. I guess he saw the
title and overlooked those...

--
~Vinod