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linux-next/drivers/platform
Javier Martinez Canillas a841178445 mfd: cros_ec: Use a zero-length array for command data
Commit 1b84f2a4cd ("mfd: cros_ec: Use fixed size arrays to transfer
data with the EC") modified the struct cros_ec_command fields to not
use pointers for the input and output buffers and use fixed length
arrays instead.

This change was made because the cros_ec ioctl API uses that struct
cros_ec_command to allow user-space to send commands to the EC and
to get data from the EC. So using pointers made the API not 64-bit
safe. Unfortunately this approach was not flexible enough for all
the use-cases since there may be a need to send larger commands
on newer versions of the EC command protocol.

So to avoid to choose a constant length that it may be too big for
most commands and thus wasting memory and CPU cycles on copy from
and to user-space or having a size that is too small for some big
commands, use a zero-length array that is both 64-bit safe and
flexible. The same buffer is used for both output and input data
so the maximum of these values should be used to allocate it.

Suggested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2015-06-15 13:18:19 +01:00
..
chrome mfd: cros_ec: Use a zero-length array for command data 2015-06-15 13:18:19 +01:00
goldfish goldfish: pipe: fix warnings for 32bit builds 2014-05-16 11:32:51 -07:00
mips MIPS: Loongson-3: Add chipset ACPI platform driver 2015-04-01 17:22:18 +02:00
olpc drivers/platform/olpc/olpc-ec.c: initialise earlier 2013-08-23 09:51:22 -07:00
x86 platform-drivers-x86 for 4.1 2015-04-26 13:44:46 -07:00
Kconfig MIPS: Loongson-3: Add CPU Hwmon platform driver 2015-04-01 17:22:17 +02:00
Makefile MIPS: Loongson-3: Add CPU Hwmon platform driver 2015-04-01 17:22:17 +02:00