Re: [PATCH v2] can: build proc support only if CONFIG_PROC_FS is activated

[Alexander Aring <aar@pengutronix.de>]

Hi,

On 06/18/2016 10:57 AM, Oliver Hartkopp wrote:
> Hi Alexander,
> 
> there's a procfs dependency of the CAN_BCM too.
> 
> On 06/17/2016 02:08 PM, Marc Kleine-Budde wrote:
>> From: Alexander Aring <aar@pengutronix.de>
>>
>> When building can subsystem with CONFIG_PROC_FS=n I detected some unused
>> variables warning by using proc functions.
> 
> Did you miss to switch on CAN_BCM when doing a CONFIG_PROC_FS disabled test?
> 

I detected the unused variable warnings while running randconfig, the
first time I didn't saw the CAN_BCM but the second time (yet another
randconfig) I saw CAN_BCM.

net/can/bcm.c:235:37: warning: ‘bcm_proc_fops’ defined but not used
[-Wunused-const-variable=]
 static const struct file_operations bcm_proc_fops = {

> Or is the procfs subsystem that intelligent that it just disables the functionality so that the users (e.g. in bcm.c) don't need to care about CONFIG_PROC_FS.
> 

It is such intelligent, but you have no static inline no-op's for
functions which returns a pointer. It's:

#define proc_fs_foobar NULL

will be used and this occurs warnings while compiling. In case of
can-proc you really don't need to link against it if CONFIG_PROC_FS
isn't set - will turn off the warnings and compiles faster.

The CAN_BCM should be fixed as well, most subsystem puts ifdefs arounds
the proc functionality if it's not well outsourced like can-proc.c.

Who will send a patch now?

- Alex