Re: [PATCH 21/34] iwlegacy: don't warn for unused variables with DEBUG_FS=n

[Andy Shevchenko]

On Wed, Apr 03, 2024 at 10:06:39AM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> The reference to il_rate_mcs is inside of an #ifdef, causing a W=1 warning:
> 
> drivers/net/wireless/intel/iwlegacy/4965-rs.c:189:38: error: unused variable 'il_rate_mcs' [-Werror,-Wunused-const-variable]
> static const struct il_rate_mcs_info il_rate_mcs[RATE_COUNT] = {
> 
> Replace the #ifdef with a PTR_IF() for better compile time analysis.
> The dead code will still get eliminated, but the warning goes away.

..

> +	.add_sta_debugfs = PTR_IF(IS_ENABLED(CONFIG_DEBUG_FS),
> +				  il4965_rs_add_debugfs),

I believe it's not the first and not the last driver that wants this kind of
thing. Maybe
- split out PTR_IF() from kernel.h
- add debugfs_ptr()
- use it?

-- 
With Best Regards,
Andy Shevchenko