[brauner-vfs:namespace-7.4.misc 6/7] kernel/user_namespace.c:787:22: warning: no previous prototype for function 'insert_extent'

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git namespace-7.4.misc
head:   34a496d638705dc227cc6dd2aaaa9e450893502f
commit: f6f1a2496ba5dcc076d7fb7aa329887cd6ae55fa [6/7] userns: Add KUnit test suite for uid_gid_map
config: s390-defconfig (https://download.01.org/0day-ci/archive/20260911/202609111305.ta3EOA2x-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260911/202609111305.ta3EOA2x-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/202609111305.ta3EOA2x-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/user_namespace.c:787:22: warning: no previous prototype for function 'insert_extent' [-Wmissing-prototypes]
     787 | VISIBLE_IF_KUNIT int insert_extent(struct uid_gid_map *map,
         |                      ^
   kernel/user_namespace.c:787:18: note: declare 'static' if the function is not intended to be used outside of this translation unit
     787 | VISIBLE_IF_KUNIT int insert_extent(struct uid_gid_map *map,
         |                  ^
         |                  static 
>> kernel/user_namespace.c:860:22: warning: no previous prototype for function 'sort_idmaps' [-Wmissing-prototypes]
     860 | VISIBLE_IF_KUNIT int sort_idmaps(struct uid_gid_map *map)
         |                      ^
   kernel/user_namespace.c:860:18: note: declare 'static' if the function is not intended to be used outside of this translation unit
     860 | VISIBLE_IF_KUNIT int sort_idmaps(struct uid_gid_map *map)
         |                  ^
         |                  static 
   2 warnings generated.


vim +/insert_extent +787 kernel/user_namespace.c

   781	
   782	/*
   783	 * insert_extent - Safely insert a new idmap extent into struct uid_gid_map.
   784	 * Takes care to allocate a 4K block of memory if the number of mappings exceeds
   785	 * UID_GID_MAP_MAX_BASE_EXTENTS.
   786	 */
 > 787	VISIBLE_IF_KUNIT int insert_extent(struct uid_gid_map *map,
   788					   struct uid_gid_extent *extent)
   789	{
   790		struct uid_gid_extent *dest;
   791	
   792		if (map->nr_extents == UID_GID_MAP_MAX_BASE_EXTENTS) {
   793			struct uid_gid_extent *forward;
   794	
   795			/* Allocate memory for 340 mappings. */
   796			forward = kmalloc_objs(struct uid_gid_extent,
   797					       UID_GID_MAP_MAX_EXTENTS);
   798			if (!forward)
   799				return -ENOMEM;
   800	
   801			/* Copy over memory. Only set up memory for the forward pointer.
   802			 * Defer the memory setup for the reverse pointer.
   803			 */
   804			memcpy(forward, map->extent,
   805			       map->nr_extents * sizeof(map->extent[0]));
   806	
   807			map->forward = forward;
   808			map->reverse = NULL;
   809		}
   810	
   811		/*
   812		 * nr_extents must be updated before the extent and forward arrays are
   813		 * accessed, otherwise KSAN will assert an out-of-bounds error.
   814		 */
   815		map->nr_extents++;
   816		if (map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
   817			dest = &map->extent[map->nr_extents - 1];
   818		else
   819			dest = &map->forward[map->nr_extents - 1];
   820	
   821		*dest = *extent;
   822		return 0;
   823	}
   824	EXPORT_SYMBOL_IF_KUNIT(insert_extent);
   825	
   826	/* cmp function to sort() forward mappings */
   827	static int cmp_extents_forward(const void *a, const void *b)
   828	{
   829		const struct uid_gid_extent *e1 = a;
   830		const struct uid_gid_extent *e2 = b;
   831	
   832		if (e1->first < e2->first)
   833			return -1;
   834	
   835		if (e1->first > e2->first)
   836			return 1;
   837	
   838		return 0;
   839	}
   840	
   841	/* cmp function to sort() reverse mappings */
   842	static int cmp_extents_reverse(const void *a, const void *b)
   843	{
   844		const struct uid_gid_extent *e1 = a;
   845		const struct uid_gid_extent *e2 = b;
   846	
   847		if (e1->lower_first < e2->lower_first)
   848			return -1;
   849	
   850		if (e1->lower_first > e2->lower_first)
   851			return 1;
   852	
   853		return 0;
   854	}
   855	
   856	/*
   857	 * sort_idmaps - Sorts an array of idmap entries.
   858	 * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
   859	 */
 > 860	VISIBLE_IF_KUNIT int sort_idmaps(struct uid_gid_map *map)
   861	{
   862		if (map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
   863			return 0;
   864	
   865		/* Sort forward array. */
   866		sort(map->forward, map->nr_extents, sizeof(struct uid_gid_extent),
   867		     cmp_extents_forward, NULL);
   868	
   869		/* Only copy the memory from forward we actually need. */
   870		map->reverse = kmemdup_array(map->forward, map->nr_extents,
   871					     sizeof(struct uid_gid_extent), GFP_KERNEL);
   872		if (!map->reverse)
   873			return -ENOMEM;
   874	
   875		/* Sort reverse array. */
   876		sort(map->reverse, map->nr_extents, sizeof(struct uid_gid_extent),
   877		     cmp_extents_reverse, NULL);
   878	
   879		return 0;
   880	}
   881	EXPORT_SYMBOL_IF_KUNIT(sort_idmaps);
   882	

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