drivers/char/nvram.c:56:21: warning: 'nvram_mutex' defined but not used

drivers/char/nvram.c:56:21: warning: 'nvram_mutex' defined but not used

[kernel test robot]

Hi Matthew,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   e1914add2799225a87502051415fc5c32aeb02ae
commit: 25500ba7e77ce9d3d9b5a1929d41a2ee2e23f6fe locking/mutex: Remove the list_head from struct mutex
date:   10 weeks ago
config: powerpc64-randconfig-002-20260514 (https://download.01.org/0day-ci/archive/20260514/202605141850.qvidrpg9-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260514/202605141850.qvidrpg9-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Fixes: 25500ba7e77c ("locking/mutex: Remove the list_head from struct mutex")
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605141850.qvidrpg9-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/seqlock.h:20,
                    from include/linux/mmzone.h:17,
                    from include/linux/gfp.h:7,
                    from include/linux/umh.h:4,
                    from include/linux/kmod.h:9,
                    from include/linux/module.h:18,
                    from drivers/char/nvram.c:34:
>> drivers/char/nvram.c:56:21: warning: 'nvram_mutex' defined but not used [-Wunused-variable]
    static DEFINE_MUTEX(nvram_mutex);
                        ^~~~~~~~~~~
   include/linux/mutex.h:87:15: note: in definition of macro 'DEFINE_MUTEX'
     struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
                  ^~~~~~~~~


vim +/nvram_mutex +56 drivers/char/nvram.c

^1da177e4c3f4152 Linus Torvalds 2005-04-16  55  
613655fa39ff6957 Arnd Bergmann  2010-06-02 @56  static DEFINE_MUTEX(nvram_mutex);
^1da177e4c3f4152 Linus Torvalds 2005-04-16  57  static DEFINE_SPINLOCK(nvram_state_lock);
^1da177e4c3f4152 Linus Torvalds 2005-04-16  58  static int nvram_open_cnt;	/* #times opened */
^1da177e4c3f4152 Linus Torvalds 2005-04-16  59  static int nvram_open_mode;	/* special open modes */
d5bbb5021ce8d9ff Finn Thain     2019-01-15  60  static ssize_t nvram_size;
^1da177e4c3f4152 Linus Torvalds 2005-04-16  61  #define NVRAM_WRITE		1 /* opened for writing (exclusive) */
^1da177e4c3f4152 Linus Torvalds 2005-04-16  62  #define NVRAM_EXCL		2 /* opened with O_EXCL */
^1da177e4c3f4152 Linus Torvalds 2005-04-16  63  

:::::: The code at line 56 was first introduced by commit
:::::: 613655fa39ff6957754fa8ceb8559980920eb8ee drivers: autoconvert trivial BKL users to private mutex

:::::: TO: Arnd Bergmann <arnd@arndb.de>
:::::: CC: Arnd Bergmann <arnd@arndb.de>

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: drivers/char/nvram.c:56:21: warning: 'nvram_mutex' defined but not used

[Geert Uytterhoeven]

On Thu, 14 May 2026 at 12:27, kernel test robot <lkp@intel.com> wrote:
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   e1914add2799225a87502051415fc5c32aeb02ae
> commit: 25500ba7e77ce9d3d9b5a1929d41a2ee2e23f6fe locking/mutex: Remove the list_head from struct mutex
> date:   10 weeks ago
> config: powerpc64-randconfig-002-20260514 (https://download.01.org/0day-ci/archive/20260514/202605141850.qvidrpg9-lkp@intel.com/config)
> compiler: powerpc64-linux-gcc (GCC) 8.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260514/202605141850.qvidrpg9-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Fixes: 25500ba7e77c ("locking/mutex: Remove the list_head from struct mutex")
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202605141850.qvidrpg9-lkp@intel.com/
>
> All warnings (new ones prefixed by >>):
>
>    In file included from include/linux/seqlock.h:20,
>                     from include/linux/mmzone.h:17,
>                     from include/linux/gfp.h:7,
>                     from include/linux/umh.h:4,
>                     from include/linux/kmod.h:9,
>                     from include/linux/module.h:18,
>                     from drivers/char/nvram.c:34:
> >> drivers/char/nvram.c:56:21: warning: 'nvram_mutex' defined but not used [-Wunused-variable]
>     static DEFINE_MUTEX(nvram_mutex);
>                         ^~~~~~~~~~~
>    include/linux/mutex.h:87:15: note: in definition of macro 'DEFINE_MUTEX'
>      struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
>                   ^~~~~~~~~

Posted fix is "[PATCH v5] char/nvram: Remove redundant nvram_mutex", see
https://lore.kernel.org/20260428061540.73668-1-venkat88@linux.ibm.com

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds