[openeuler:OLK-6.6 2304/2304] mm/page_cache_limit.c:94:5: warning: no previous prototype for 'cache_limit_mbytes_sysctl_handler'

28 May 2025

      Hi Ze,

FYI, the error/warning still remains.

tree:   https://gitee.com/openeuler/kernel.git OLK-6.6
head:   35c5792a71f249ce79eba3cbb546d1ece7c4f3ee
commit: 7d1031b36ebd6c273d9aad316fd9e3e2daa01a85 [2304/2304] mm: support pagecache limit
config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20250528/202505280023.4g7q598y-lkp@i...)
compiler: loongarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250528/202505280023.4g7q598y-lkp@i...)

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/202505280023.4g7q598y-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/page_cache_limit.c:61:5: warning: no previous prototype for 'cache_reclaim_enable_handler' [-Wmissing-prototypes]
      61 | int cache_reclaim_enable_handler(struct ctl_table *table, int write,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   mm/page_cache_limit.c:77:5: warning: no previous prototype for 'cache_reclaim_sysctl_handler' [-Wmissing-prototypes]
      77 | int cache_reclaim_sysctl_handler(struct ctl_table *table, int write,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
...
...
mm/page_cache_limit.c:94:5: warning: no previous prototype for 'cache_limit_mbytes_sysctl_handler' [-Wmissing-prototypes]
      94 | int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/cache_limit_mbytes_sysctl_handler +94 mm/page_cache_limit.c

    60
...
61	int cache_reclaim_enable_handler(struct ctl_table *table, int write,
    62				void *buffer, size_t *length, loff_t *ppos)
    63	{
    64		int ret;
    65	
    66		ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
    67		if (ret || !write)
    68			return ret;
    69	
    70		if (should_periodical_reclaim())
    71			schedule_delayed_work(&shepherd, round_jiffies_relative(
    72				(unsigned long)vm_cache_reclaim_s * HZ));
    73	
    74		return 0;
    75	}
    76	
    77	int cache_reclaim_sysctl_handler(struct ctl_table *table, int write,
    78			void *buffer, size_t *length, loff_t *ppos)
    79	{
    80		int ret;
    81	
    82		ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
    83		if (ret || !write)
    84			return ret;
    85	
    86		if (should_periodical_reclaim())
    87			mod_delayed_work(system_unbound_wq, &shepherd,
    88					round_jiffies_relative(
    89					(unsigned long)vm_cache_reclaim_s * HZ));
    90	
    91		return ret;
    92	}
    93	
94	int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write,
    95			void __user *buffer, size_t *length, loff_t *ppos)
    96	{
    97		int ret;
    98		unsigned long vm_cache_limit_mbytes_max;
    99		unsigned long origin_mbytes = vm_cache_limit_mbytes;
   100		int nr_retries = MAX_RECLAIM_RETRIES;
   101	
   102		vm_cache_limit_mbytes_max = totalram_pages() >> (20 - PAGE_SHIFT);
   103		ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
   104		if (ret || !write)
   105			return ret;
   106	
   107		if (vm_cache_limit_mbytes > vm_cache_limit_mbytes_max) {
   108			vm_cache_limit_mbytes = origin_mbytes;
   109			return -EINVAL;
   110		}
   111	
   112		if (write) {
   113			while (should_reclaim_page_cache() && page_cache_over_limit() &&
   114					nr_retries--) {
   115				if (signal_pending(current))
   116					return -EINTR;
   117	
   118				shrink_memory(node_reclaim_num(), false);
   119			}
   120		}
   121	
   122		return 0;
   123	}
   124
-- 
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