[PATCH] drm: refactor call to request_module

[PATCH] drm: refactor call to request_module

[Kees Cook]

This reduces the size of the stack frame when calling request_module().
Performing the sprintf before the call is not needed.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/gpu/drm/drm_encoder_slave.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_encoder_slave.c b/drivers/gpu/drm/drm_encoder_slave.c
index 48c52f7..0cfb60f 100644
--- a/drivers/gpu/drm/drm_encoder_slave.c
+++ b/drivers/gpu/drm/drm_encoder_slave.c
@@ -54,16 +54,12 @@ int drm_i2c_encoder_init(struct drm_device *dev,
 			 struct i2c_adapter *adap,
 			 const struct i2c_board_info *info)
 {
-	char modalias[sizeof(I2C_MODULE_PREFIX)
-		      + I2C_NAME_SIZE];
 	struct module *module = NULL;
 	struct i2c_client *client;
 	struct drm_i2c_encoder_driver *encoder_drv;
 	int err = 0;
 
-	snprintf(modalias, sizeof(modalias),
-		 "%s%s", I2C_MODULE_PREFIX, info->type);
-	request_module(modalias);
+	request_module("%s%s", I2C_MODULE_PREFIX, info->type);
 
 	client = i2c_new_device(adap, info);
 	if (!client) {
-- 
1.7.9.5


-- 
Kees Cook
Chrome OS Security

Re: [PATCH] drm: refactor call to request_module

[Paul Menzel]

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Am Dienstag, den 07.05.2013, 12:32 -0700 schrieb Kees Cook:
> This reduces the size of the stack frame when calling request_module().
> Performing the sprintf before the call is not needed.

Good fine. Do you have any hard numbers for the record?

Did you find this just by reading the code or are there any problems
with stack sizes on some systems?

(This patch would be good alone for decreasing the number of code
lines. ;-))

> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/gpu/drm/drm_encoder_slave.c |    6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)

Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>


Thanks,

Paul

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Re: [PATCH] drm: refactor call to request_module

[Kees Cook]

On Wed, May 8, 2013 at 12:22 AM, Paul Menzel
<paulepanter@users.sourceforge.net> wrote:
> Am Dienstag, den 07.05.2013, 12:32 -0700 schrieb Kees Cook:
>> This reduces the size of the stack frame when calling request_module().
>> Performing the sprintf before the call is not needed.
>
> Good fine. Do you have any hard numbers for the record?
>
> Did you find this just by reading the code or are there any problems
> with stack sizes on some systems?
>
> (This patch would be good alone for decreasing the number of code
> lines. ;-))

No hard numbers; I just saw it while reviewing callers to request_module(). :)

>> Signed-off-by: Kees Cook <keescook@chromium.org>
>> ---
>>  drivers/gpu/drm/drm_encoder_slave.c |    6 +-----
>>  1 file changed, 1 insertion(+), 5 deletions(-)
>
> Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>

Thanks!

-Kees

--
Kees Cook
Chrome OS Security