drivers/char/nvram.c defines a static mutex 'nvram_mutex' which is never
used. This results in a compiler warning on linux-next builds:

  warning: 'nvram_mutex' defined but not used [-Wunused-variable]

Remove the unused definition to avoid the warning.

Signed-off-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
---
 drivers/char/nvram.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index 9eff426a9286..2ce3307663ed 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -53,7 +53,7 @@
 #include <asm/nvram.h>
 #endif
 
-static DEFINE_MUTEX(nvram_mutex);
+static __maybe_unused DEFINE_MUTEX(nvram_mutex);
 static DEFINE_SPINLOCK(nvram_state_lock);
 static int nvram_open_cnt;	/* #times opened */
 static int nvram_open_mode;	/* special open modes */
-- 
2.45.2

On Mon, Mar 23, 2026 at 12:54:22PM +0530, Venkat Rao Bagalkote wrote:
> drivers/char/nvram.c defines a static mutex 'nvram_mutex' which is never
> used. This results in a compiler warning on linux-next builds:
> 
>   warning: 'nvram_mutex' defined but not used [-Wunused-variable]
> 
> Remove the unused definition to avoid the warning.
> 
> Signed-off-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> ---
>  drivers/char/nvram.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
> index 9eff426a9286..2ce3307663ed 100644
> --- a/drivers/char/nvram.c
> +++ b/drivers/char/nvram.c
> @@ -53,7 +53,7 @@
>  #include <asm/nvram.h>
>  #endif
>  
> -static DEFINE_MUTEX(nvram_mutex);
> +static __maybe_unused DEFINE_MUTEX(nvram_mutex);

If it is never used, why not actually delete it?  This just papers over
the real issue :(

thanks,

greg k-h

On Mon, Mar 23, 2026, at 08:36, Greg KH wrote:
> On Mon, Mar 23, 2026 at 12:54:22PM +0530, Venkat Rao Bagalkote wrote:
>> drivers/char/nvram.c defines a static mutex 'nvram_mutex' which is never
>> used. This results in a compiler warning on linux-next builds:
>> 
>>   warning: 'nvram_mutex' defined but not used [-Wunused-variable]
>> 
>> Remove the unused definition to avoid the warning.
>> 
>> Signed-off-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
>> ---
>>  drivers/char/nvram.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
>> index 9eff426a9286..2ce3307663ed 100644
>> --- a/drivers/char/nvram.c
>> +++ b/drivers/char/nvram.c
>> @@ -53,7 +53,7 @@
>>  #include <asm/nvram.h>
>>  #endif
>>  
>> -static DEFINE_MUTEX(nvram_mutex);
>> +static __maybe_unused DEFINE_MUTEX(nvram_mutex);
>
> If it is never used, why not actually delete it?  This just papers over
> the real issue :(

It's used on ppc32, atari and x86, but not ppc64.

However, I see that all the implementations that have the
mutex in their code path also have an inner spinlock that
does the same thing, while the mutex is a renmant from my
613655fa39ff ("drivers: autoconvert trivial BKL users to
private mutex").

I'm fairly sure we can actually remove it.

      Arnd

Please ignore this. Sent v2 [1]

[1]: 
https://lore.kernel.org/all/20260323073220.25798-1-venkat88@linux.ibm.com/


Regards,

Venkat.

On 23/03/26 12:54 pm, Venkat Rao Bagalkote wrote:
> drivers/char/nvram.c defines a static mutex 'nvram_mutex' which is never
> used. This results in a compiler warning on linux-next builds:
>
>    warning: 'nvram_mutex' defined but not used [-Wunused-variable]
>
> Remove the unused definition to avoid the warning.
>
> Signed-off-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> ---
>   drivers/char/nvram.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
> index 9eff426a9286..2ce3307663ed 100644
> --- a/drivers/char/nvram.c
> +++ b/drivers/char/nvram.c
> @@ -53,7 +53,7 @@
>   #include <asm/nvram.h>
>   #endif
>   
> -static DEFINE_MUTEX(nvram_mutex);
> +static __maybe_unused DEFINE_MUTEX(nvram_mutex);
>   static DEFINE_SPINLOCK(nvram_state_lock);
>   static int nvram_open_cnt;	/* #times opened */
>   static int nvram_open_mode;	/* special open modes */