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: <d120d5000710151033u44df579fr82588a7a6c7065d@mail.gmail.com>
Date:	Mon, 15 Oct 2007 13:33:31 -0400
From:	"Dmitry Torokhov" <dmitry.torokhov@...il.com>
To:	"Hennerich, Michael" <Michael.Hennerich@...log.com>
Cc:	"Bryan Wu" <bryan.wu@...log.com>,
	linux-input@...ey.karlin.mff.cuni.cz,
	linux-joystick@...ey.karlin.mff.cuni.cz,
	linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org
Subject: Re: [PATCH 2/3] Input/Touchscreen Driver: add support AD7877 touchscreen driver

Hi Michael,

On 10/15/07, Hennerich, Michael <Michael.Hennerich@...log.com> wrote:
> >
> >> +
> >> +static int ad7877_read(struct device *dev, u16 reg)
> >> +{
> >> +       struct spi_device       *spi = to_spi_device(dev);
> >> +       struct ser_req          *req = kzalloc(sizeof *req,
> GFP_KERNEL);
> >
> >How many reads can happen at once? Maybe allocate 1 ser_req per
> >touchcsreen when creating it?
>
> ad7877_read_adc, ad7877_read and ad7877_write are just used by the sysfs
> hooks. Touchscreen samples are read by the kthread using a different
> message struct. So far each sysfs invocation got its own storage for the
> spi message, which then is handed over to the SPI bus driver.
> The SPI bus driver serializes transfers in a kthread.
>
> Two different processes could access the drivers sysfs hooks.
>
> Using one ser_req per touch screen could require additional locking?
> Things at is, looks pretty safe to me.
>

OK, fair enough.

-- 
Dmitry
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ