linux-kernel - Re: [PATCH v1 00/12] Improvements for Tegra I2C driver

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] [day] [month] [year] [list]

Message-ID: <e1b7a9fc-e638-8576-a79e-7c2cf1cfbfe2@gmail.com>
Date:   Fri, 4 Sep 2020 01:18:15 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 00/12] Improvements for Tegra I2C driver

03.09.2020 19:47, Michał Mirosław пишет:
> On Thu, Sep 03, 2020 at 04:12:13AM +0300, Dmitry Osipenko wrote:
>> 03.09.2020 00:20, Michał Mirosław пишет:
>>> BTW, I wonder if you could expose i2c_in_atomic_xfer_mode() and use it
>>> to differentiate atomic_xfer from normal and get rid of the internal
>>> flag and .master_xfer_atomic callback.
>>
>> The atomic transfer uses 90% of the code path that a non-atomic transfer
>> uses. I don't see how it could be exposed without duplicated lots of the
>> code, unless I'm not missing what you're suggesting.
> 
> The I2C core falls back to .master_xfer even in atomic mode if
> .master_xfer_atomic is NULL, so what I'm suggesting is to make
> i2c_in_atomic_xfer_mode() public (from i2c-core.h) and use it in
> normal .master_xfer to choose atomic wait variants.

Okay, I see now. But the I2C core prints a noisy warning if
master_xfer_atomic is NULL in atomic transfer, so I'm not sure whether
changing all that code will bring much benefits to us and anyone else.
It's a bit too questionable change to me, but maybe I'm still missing
something. Will be great if you could provide an example patch.