[android-common:android14-kiwi-6.1 40/40] mm/vmscan.c:997:15: warning: no previous prototype for 'shrink_slab'

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

tree:   https://android.googlesource.com/kernel/common android14-kiwi-6.1
head:   ebacb5ab3a1e5bf8dc788a29244f0e68d00a5bd6
commit: 09ab235661116880b7ea9b4deb705802f2c19ab4 [40/40] ANDROID: vendor_hooks: export shrink_slab
config: x86_64-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20251214/202512140735.mFuS8dbH-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251214/202512140735.mFuS8dbH-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/202512140735.mFuS8dbH-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/vmscan.c:997:15: warning: no previous prototype for 'shrink_slab' [-Wmissing-prototypes]
     997 | unsigned long shrink_slab(gfp_t gfp_mask, int nid,
         |               ^~~~~~~~~~~


vim +/shrink_slab +997 mm/vmscan.c

   976	
   977	/**
   978	 * shrink_slab - shrink slab caches
   979	 * @gfp_mask: allocation context
   980	 * @nid: node whose slab caches to target
   981	 * @memcg: memory cgroup whose slab caches to target
   982	 * @priority: the reclaim priority
   983	 *
   984	 * Call the shrink functions to age shrinkable caches.
   985	 *
   986	 * @nid is passed along to shrinkers with SHRINKER_NUMA_AWARE set,
   987	 * unaware shrinkers will receive a node id of 0 instead.
   988	 *
   989	 * @memcg specifies the memory cgroup to target. Unaware shrinkers
   990	 * are called only if it is the root cgroup.
   991	 *
   992	 * @priority is sc->priority, we take the number of objects and >> by priority
   993	 * in order to get the scan target.
   994	 *
   995	 * Returns the number of reclaimed slab objects.
   996	 */
 > 997	unsigned long shrink_slab(gfp_t gfp_mask, int nid,
   998					 struct mem_cgroup *memcg,
   999					 int priority)
  1000	{
  1001		unsigned long ret, freed = 0;
  1002		struct shrinker *shrinker;
  1003		bool bypass = false;
  1004	
  1005		trace_android_vh_shrink_slab_bypass(gfp_mask, nid, memcg, priority, &bypass);
  1006		if (bypass)
  1007			return 0;
  1008	
  1009		/*
  1010		 * The root memcg might be allocated even though memcg is disabled
  1011		 * via "cgroup_disable=memory" boot parameter.  This could make
  1012		 * mem_cgroup_is_root() return false, then just run memcg slab
  1013		 * shrink, but skip global shrink.  This may result in premature
  1014		 * oom.
  1015		 */
  1016		if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg))
  1017			return shrink_slab_memcg(gfp_mask, nid, memcg, priority);
  1018	
  1019		if (!down_read_trylock(&shrinker_rwsem))
  1020			goto out;
  1021	
  1022		list_for_each_entry(shrinker, &shrinker_list, list) {
  1023			struct shrink_control sc = {
  1024				.gfp_mask = gfp_mask,
  1025				.nid = nid,
  1026				.memcg = memcg,
  1027			};
  1028	
  1029			ret = do_shrink_slab(&sc, shrinker, priority);
  1030			if (ret == SHRINK_EMPTY)
  1031				ret = 0;
  1032			freed += ret;
  1033			/*
  1034			 * Bail out if someone want to register a new shrinker to
  1035			 * prevent the registration from being stalled for long periods
  1036			 * by parallel ongoing shrinking.
  1037			 */
  1038			if (rwsem_is_contended(&shrinker_rwsem)) {
  1039				freed = freed ? : 1;
  1040				break;
  1041			}
  1042		}
  1043	
  1044		up_read(&shrinker_rwsem);
  1045	out:
  1046		cond_resched();
  1047		return freed;
  1048	}
  1049	

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