[jlayton:uek-localio 2037/2262] fs/dcache.c:1531:15: error: call to undeclared function 'get_nr_dentry'; ISO C99 and later do not support implicit function declarations

[jlayton:uek-localio 2037/2262] fs/dcache.c:1531:15: error: call to undeclared function 'get_nr_dentry'; ISO C99 and later do not support implicit function declarations

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git uek-localio
head:   65b0dc6bb1f5c18e63d8ee9ea1cca997456a81a9
commit: fbc8f7ca2ebf9db96aa3263c657ea2840840bdec [2037/2262] fs/dcache: Estimate the number of negative dentries to prune per filesystem
config: hexagon-randconfig-002-20250524 (https://download.01.org/0day-ci/archive/20250524/202505241641.cjNXyGVb-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250524/202505241641.cjNXyGVb-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/202505241641.cjNXyGVb-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from fs/dcache.c:31:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:23:
   In file included from include/linux/writeback.h:13:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   include/linux/highmem.h:265:2: error: call to undeclared function 'clear_user_page_uncached'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     265 |         clear_user_page_uncached(addr, vaddr, page);
         |         ^
   include/linux/highmem.h:265:2: note: did you mean 'clear_user_highpage_uncached'?
   include/linux/highmem.h:261:20: note: 'clear_user_highpage_uncached' declared here
     261 | static inline void clear_user_highpage_uncached(struct page *page, unsigned long vaddr)
         |                    ^
     262 | {
     263 |         void *addr = kmap_atomic(page);
     264 | 
     265 |         clear_user_page_uncached(addr, vaddr, page);
         |         ~~~~~~~~~~~~~~~~~~~~~~~~
         |         clear_user_highpage_uncached
   fs/dcache.c:1530:19: error: call to undeclared function 'get_nr_dentry_negative'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1530 |         long count_neg = get_nr_dentry_negative();
         |                          ^
>> fs/dcache.c:1531:15: error: call to undeclared function 'get_nr_dentry'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1531 |         long count = get_nr_dentry();
         |                      ^
   fs/dcache.c:1531:15: note: did you mean 'retain_dentry'?
   fs/dcache.c:944:20: note: 'retain_dentry' declared here
     944 | static inline bool retain_dentry(struct dentry *dentry, bool locked)
         |                    ^
   fs/dcache.c:1616:10: error: call to undeclared function 'get_nr_dentry_negative'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1616 |         count = get_nr_dentry_negative();
         |                 ^
   fs/dcache.c:1610:7: warning: variable 'last_n_neg' set but not used [-Wunused-but-set-variable]
    1610 |         long last_n_neg, excess, count;
         |              ^
   1 warning and 4 errors generated.


vim +/get_nr_dentry +1531 fs/dcache.c

  1521	
  1522	/*
  1523	 * Prune dentries from a super block.
  1524	 */
  1525	static void prune_negative_one_sb(struct super_block *sb, void *arg)
  1526	{
  1527		unsigned long freed = 0, scan_once = 0, this_sb_freed = 0;
  1528		long limit, lower_limit, this_sb_dentries, excess, prune_this_sb = 0;
  1529		int this_sb_pc = 0;
  1530		long count_neg = get_nr_dentry_negative();
> 1531		long count = get_nr_dentry();
  1532		struct prune_negative_ctrl *ctrl = arg;
  1533		LIST_HEAD(dispose);
  1534	
  1535		limit = neg_dentry_nfree_init + ctrl->prune_ncpus * neg_dentry_percpu_limit;
  1536	
  1537		/*
  1538		 * If the -ve dentry count is within the limit
  1539		 * and a prune is not on then do nothing.
  1540		 */
  1541		if (limit >= count_neg && !(ndblk.nprune_on))
  1542			return;
  1543	
  1544		/*
  1545		 * Set the prune on when the -ve
  1546		 * dentry count crosses the limit.
  1547		 */
  1548		if (!(ndblk.nprune_on) && (count_neg > limit))
  1549			ndblk.nprune_on = 1;
  1550	
  1551		/*
  1552		 * Add extra 30% so that once pruning starts,
  1553		 * it continues until we reach 70% of the limit.
  1554		 */
  1555		lower_limit = ctrl->prune_ncpus * (neg_dentry_percpu_limit -
  1556					((neg_dentry_percpu_limit * 30)/ 100));
  1557		/*
  1558		 * Set the prune off when the -ve dentry
  1559		 * count reaches the lower limit.
  1560		 */
  1561		if (count_neg <= lower_limit) {
  1562			ndblk.nprune_on = 0;
  1563			return;
  1564		}
  1565	
  1566		/*
  1567		 * Dentry to prune from this super block's LRU should be
  1568		 * proportional to the ratio of dentries present in this
  1569		 * SB's LRU to the total dentries present in the system.
  1570		 * Also, try to skip inmemory filesystems.
  1571		 */
  1572		this_sb_dentries = list_lru_elems(&sb->s_dentry_lru);
  1573		if (!this_sb_dentries)
  1574			return;
  1575		this_sb_pc = (this_sb_dentries * 100) / count;
  1576		if (!this_sb_pc)
  1577			this_sb_pc = 1;
  1578	
  1579		excess = count_neg - lower_limit;
  1580		prune_this_sb = (excess * this_sb_pc) / 100;
  1581		if (!prune_this_sb)
  1582			return; /* Negligible, skip this sb */
  1583	
  1584		if (ctrl->prune_percent) {
  1585			if (prune_this_sb > NEG_WALKING_CAP)
  1586				scan_once = NEG_WALKING_CAP;
  1587			else
  1588				scan_once = prune_this_sb;
  1589	
  1590			freed = list_lru_walk_all_nodes(&sb->s_dentry_lru,
  1591						dentry_negative_lru_isolate,
  1592						&dispose, this_sb_dentries, scan_once);
  1593			if (freed) {
  1594				shrink_dentry_list(&dispose);
  1595				this_sb_freed += freed;
  1596			}
  1597			ctrl->prune_count += this_sb_freed;
  1598		}
  1599	}
  1600	

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