Re: [PATCH v2 1/2] fs/proc: optimize exactly register one ctl_table

[kernel test robot]

Hi Meng,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mcgrof/sysctl-next]
[also build test WARNING on jack-fs/fsnotify rostedt-trace/for-next linus/master v5.17-rc6 next-20220301]
[cannot apply to kees/for-next/pstore]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Meng-Tang/fs-proc-optimize-exactly-register-one-ctl_table/20220301-195515
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git sysctl-next
config: alpha-buildonly-randconfig-r001-20220301 (https://download.01.org/0day-ci/archive/20220302/202203020000.IeIVyxMv-lkp@xxxxxxxxx/config)
compiler: alpha-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/d9e9a410cf46b383390d668770fff70540e27528
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Meng-Tang/fs-proc-optimize-exactly-register-one-ctl_table/20220301-195515
        git checkout d9e9a410cf46b383390d668770fff70540e27528
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=alpha SHELL=/bin/bash fs/proc/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   fs/proc/proc_sysctl.c: In function 'new_links_single':
>> fs/proc/proc_sysctl.c:1281:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
    1281 |         int len = strlen(table->procname) + 1;
         |         ^~~
   fs/proc/proc_sysctl.c: At top level:
>> fs/proc/proc_sysctl.c:1638:26: warning: no previous prototype for '__register_sysctl_table_single' [-Wmissing-prototypes]
    1638 | struct ctl_table_header *__register_sysctl_table_single(
         |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/proc/proc_sysctl.c: In function 'put_links_single':
   fs/proc/proc_sysctl.c:1988:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
    1988 |         struct ctl_table_header *link_head;
         |         ^~~~~~


vim +1281 fs/proc/proc_sysctl.c

  1256	
  1257	static struct ctl_table_header *new_links_single(struct ctl_dir *dir, struct ctl_table *table,
  1258		struct ctl_table_root *link_root)
  1259	{
  1260		struct ctl_table *link_table;
  1261		struct ctl_table_header *links;
  1262		struct ctl_node *node;
  1263		char *link_name;
  1264		int name_bytes = 0;
  1265	
  1266		name_bytes += strlen(table->procname) + 1;
  1267	
  1268		links = kzalloc(sizeof(struct ctl_table_header) +
  1269				sizeof(struct ctl_node) +
  1270				sizeof(struct ctl_table)*2 +
  1271				name_bytes,
  1272				GFP_KERNEL);
  1273	
  1274		if (!links)
  1275			return NULL;
  1276	
  1277		node = (struct ctl_node *)(links + 1);
  1278		link_table = (struct ctl_table *)(node + 1);
  1279		link_name = (char *)&link_table[2];
  1280	
> 1281		int len = strlen(table->procname) + 1;
  1282	
  1283		memcpy(link_name, table->procname, len);
  1284		link_table->procname = link_name;
  1285		link_table->mode = S_IFLNK|S_IRWXUGO;
  1286		link_table->data = link_root;
  1287		link_name += len;
  1288	
  1289		init_header_single(links, dir->header.root, dir->header.set, node, link_table);
  1290		links->nreg = 1;
  1291	
  1292		return links;
  1293	}
  1294	static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
  1295		struct ctl_table_root *link_root)
  1296	{
  1297		struct ctl_table *link_table, *entry, *link;
  1298		struct ctl_table_header *links;
  1299		struct ctl_node *node;
  1300		char *link_name;
  1301		int nr_entries, name_bytes;
  1302	
  1303		name_bytes = 0;
  1304		nr_entries = 0;
  1305		for (entry = table; entry->procname; entry++) {
  1306			nr_entries++;
  1307			name_bytes += strlen(entry->procname) + 1;
  1308		}
  1309	
  1310		links = kzalloc(sizeof(struct ctl_table_header) +
  1311				sizeof(struct ctl_node)*nr_entries +
  1312				sizeof(struct ctl_table)*(nr_entries + 1) +
  1313				name_bytes,
  1314				GFP_KERNEL);
  1315	
  1316		if (!links)
  1317			return NULL;
  1318	
  1319		node = (struct ctl_node *)(links + 1);
  1320		link_table = (struct ctl_table *)(node + nr_entries);
  1321		link_name = (char *)&link_table[nr_entries + 1];
  1322	
  1323		for (link = link_table, entry = table; entry->procname; link++, entry++) {
  1324			int len = strlen(entry->procname) + 1;
  1325			memcpy(link_name, entry->procname, len);
  1326			link->procname = link_name;
  1327			link->mode = S_IFLNK|S_IRWXUGO;
  1328			link->data = link_root;
  1329			link_name += len;
  1330		}
  1331		init_header(links, dir->header.root, dir->header.set, node, link_table);
  1332		links->nreg = nr_entries;
  1333	
  1334		return links;
  1335	}
  1336	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx