linux-kernel - Re: [PATCH] gpio: use raw spinlock for gpio chip shadowed data

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: <CAHp75VfcxACmuw5pwPgSB9ud06hWtHCUrMifU1rZJ+h+dwG+bg@mail.gmail.com>
Date:   Mon, 18 Apr 2022 14:38:24 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Schspa Shi <schspa@...il.com>
Cc:     "brgl@...ev.pl" <brgl@...ev.pl>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "fancer.lancer@...il.com" <fancer.lancer@...il.com>,
        "hoan@...amperecomputing.com" <hoan@...amperecomputing.com>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "opendmb@...il.com" <opendmb@...il.com>
Subject: Re: [PATCH] gpio: use raw spinlock for gpio chip shadowed data

On Mon, Apr 18, 2022 at 6:07 AM Schspa Shi <schspa@...il.com> wrote:
> Andy Shevchenko <andy.shevchenko@...il.com> writes:

...

> >   drivers/gpio/gpio-mmio.c    | 22 +++++++++++-----------
> >   include/linux/gpio/driver.h |  2 +-
> >
> > You can’t do it for one driver only. As I told it will require too much of additional churn to make this to be series.
> >
>
> It seems I have misunderstood your "too much of additional churn". Can
> you explain it?
> The gpio-mmio.c and driver.h here are the basics of other gpio
> drivers. In my opinion, these two files
> belong to the basic code of gpio, and functions such as bgpio_init are
> declared in
> include/linux/gpio/driver.h and implemented in
> drivers/gpio/gpio-mmio.c. So there is no churn.

When you change the member of the data structure, you have to change
all its users. You can't change only one at a time because it will be
a (compile-time) bisectability issue.

-- 
With Best Regards,
Andy Shevchenko