[akpm-mm:mm-nonmm-unstable 15/17] lib/cpumask.c:61: warning: cannot understand function prototype: 'struct kmem_cache *cpumask_cache __ro_after_init; '

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable
head:   fa63bc7d26007e1353fa90bb06cc37966bd1513a
commit: 61ec2810d92f31b0ef8b30b08ee1d1e1ffc45ddc [15/17] cpumask: create dedicated kmem cache for cpumask var
config: parisc-defconfig (https://download.01.org/0day-ci/archive/20240320/202403202344.Aao4CzXG-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240320/202403202344.Aao4CzXG-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
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202403202344.Aao4CzXG-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> lib/cpumask.c:61: warning: cannot understand function prototype: 'struct kmem_cache *cpumask_cache __ro_after_init; '


vim +61 lib/cpumask.c

    41	
    42	/* These are not inline because of header tangles. */
    43	#ifdef CONFIG_CPUMASK_OFFSTACK
    44	/**
    45	 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
    46	 * @mask: pointer to cpumask_var_t where the cpumask is returned
    47	 * @flags: GFP_ flags
    48	 * @node: memory node from which to allocate or %NUMA_NO_NODE
    49	 *
    50	 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
    51	 * a nop returning a constant 1 (in <linux/cpumask.h>).
    52	 *
    53	 * Return: TRUE if memory allocation succeeded, FALSE otherwise.
    54	 *
    55	 * In addition, mask will be NULL if this fails.  Note that gcc is
    56	 * usually smart enough to know that mask can never be NULL if
    57	 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
    58	 * too.
    59	 */
    60	
  > 61	static struct kmem_cache *cpumask_cache __ro_after_init;
    62	

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