linux-kernel - Re: [PATCH v7] spi: sun4i: Allow transfers larger than FIFO size

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20161027212727.leqg3gvwhd3u64er@lukather>
Date:   Thu, 27 Oct 2016 23:27:27 +0200
From:   Maxime Ripard <maxime.ripard@...e-electrons.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Alexandru Gagniuc <mr.nuke.me@...il.com>, wens@...e.org,
        linux-spi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7] spi: sun4i: Allow transfers larger than FIFO size

Hi Mark,

On Thu, Oct 27, 2016 at 12:14:19PM +0100, Mark Brown wrote:
> On Wed, Oct 26, 2016 at 10:55:28AM +0200, Maxime Ripard wrote:
> > On Wed, Oct 26, 2016 at 12:00:30AM -0700, Alexandru Gagniuc wrote:
> 
> > > When DMA finally takes over, this fallback path is not mutually exclusive.
> 
> > I definitely agree, and we had this patch in the CHIP kernel for quite
> > some time, working like a charm.
> 
> > I was planning to respin it in the next few days, glad to see you took
> > care of it :)
> 
> > Mark, any comments on this? For the record, it already has my Acked-by.
> 
> Without knowing what the previous discussion was it's hard to comment,
> it sounds like some prior review comments are just being ignored here
> but since I'm not turning up anything with this subject line I've no
> idea what that might have been (and that's very concerning in itself
> given that this is apparently v7...).

v4 was here: https://patchwork.kernel.org/patch/3893371/
v5: https://patchwork.kernel.org/patch/5455381/
v6: https://patchwork.kernel.org/patch/6975871/

So basically, I really have no idea why, but it really seems like it
was just falling through the cracks, repeatedly (I'm not puting the
blame on anyone though, it just happened). Maybe it was just because
of the lack of comments :)

> I'm also concerned that there isn't a version of this for sun6i,
> it's going to make all the cut'n'pasting between the two drivers
> harder if we make changes in one and not the other.

I think I'll give reg_field a shot though, and try to merge the sun6i
driver into this one and see the results. If it can help your
decision.

> If the concern from the previous reviews to do with not using DMA is
> there some reason it's hard to do DMA?

I think just like Alexandru that it is orthogonal. But to really
answer, no, it's not difficult. There's just been some fundamental
disagreement on whether DMA was supposed to be optional or not that
stalled everything I guess.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Download attachment "signature.asc" of type "application/pgp-signature" (802 bytes)