From: Javier Martinez Canillas Date: Tue, 9 Jun 2015 11:04:42 +0000 (+0200) Subject: mfd: cros_ec: Use a zero-length array for command data X-Git-Tag: omap-for-v4.3/legacy-v2-signed~173^2~36^3~8 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a841178445bb72a3d566b4e6ab9d19e9b002eb47;p=pandora-kernel.git mfd: cros_ec: Use a zero-length array for command data Commit 1b84f2a4cd4a ("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 Signed-off-by: Javier Martinez Canillas Tested-by: Heiko Stuebner Acked-by: Lee Jones Acked-by: Olof Johansson Signed-off-by: Lee Jones --- Reading git-diff-tree failed