Sysctls are being moved out of kernel/sysctl.c and out to
their own respective subsystems / users to help with easier
maintance and avoid merge conflicts. But when we move just
one entry and to its own new file the last entry for this
new file must be empty, so we are essentialy bloating the
kernel one extra empty entry per each newly moved sysctl.
To help with this, this adds support for registering just
one ctl_table, therefore not bloating the kernel when we
move a single ctl_table to its own file.
Suggested-by: Matthew Wilcox <[email protected]>
Signed-off-by: Meng Tang <[email protected]>
---
fs/proc/proc_sysctl.c | 346 +++++++++++++++++++++++++++++++++++++++++
include/linux/sysctl.h | 3 +
2 files changed, 349 insertions(+)
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 6c87c99f0856..28c54e494c6a 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -101,7 +101,9 @@ static void drop_sysctl_table(struct ctl_table_header *header);
static int sysctl_follow_link(struct ctl_table_header **phead,
struct ctl_table **pentry);
static int insert_links(struct ctl_table_header *head);
+static int insert_links_single(struct ctl_table_header *head);
static void put_links(struct ctl_table_header *header);
+static void put_links_single(struct ctl_table_header *header);
static void sysctl_print_dir(struct ctl_dir *dir)
{
@@ -198,6 +200,25 @@ static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry)
rb_erase(node, &head->parent->root);
}
+static void init_header_single(struct ctl_table_header *head,
+ struct ctl_table_root *root, struct ctl_table_set *set,
+ struct ctl_node *node, struct ctl_table *table)
+{
+ head->ctl_table = table;
+ head->ctl_table_arg = table;
+ head->used = 0;
+ head->count = 1;
+ head->nreg = 1;
+ head->unregistering = NULL;
+ head->root = root;
+ head->set = set;
+ head->parent = NULL;
+ head->node = node;
+ INIT_HLIST_HEAD(&head->inodes);
+ if (node)
+ node->header = head;
+}
+
static void init_header(struct ctl_table_header *head,
struct ctl_table_root *root, struct ctl_table_set *set,
struct ctl_node *node, struct ctl_table *table)
@@ -227,6 +248,42 @@ static void erase_header(struct ctl_table_header *head)
erase_entry(head, entry);
}
+static int insert_header_single(struct ctl_dir *dir, struct ctl_table_header *header)
+{
+ int err;
+
+ /* Is this a permanently empty directory? */
+ if (is_empty_dir(&dir->header))
+ return -EROFS;
+
+ /* Am I creating a permanently empty directory? */
+ if (header->ctl_table == sysctl_mount_point) {
+ if (!RB_EMPTY_ROOT(&dir->root))
+ return -EINVAL;
+ set_empty_dir(dir);
+ }
+
+ dir->header.nreg++;
+ header->parent = dir;
+ err = insert_links_single(header);
+ if (err)
+ goto fail_links;
+
+ err = insert_entry(header, header->ctl_table);
+ if (err)
+ goto fail;
+
+ return 0;
+fail:
+ erase_entry(header, header->ctl_table);
+ put_links_single(header);
+fail_links:
+ if (header->ctl_table == sysctl_mount_point)
+ clear_empty_dir(dir);
+ header->parent = NULL;
+ drop_sysctl_table(&dir->header);
+ return err;
+}
static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
{
struct ctl_table *entry;
@@ -1128,6 +1185,40 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
return err;
}
+static int sysctl_check_table_single(const char *path, struct ctl_table *table)
+{
+ int err = 0;
+
+ if (table->child)
+ err |= sysctl_err(path, table, "Not a file");
+
+ if ((table->proc_handler == proc_dostring) ||
+ (table->proc_handler == proc_dointvec) ||
+ (table->proc_handler == proc_douintvec) ||
+ (table->proc_handler == proc_douintvec_minmax) ||
+ (table->proc_handler == proc_dointvec_minmax) ||
+ (table->proc_handler == proc_dou8vec_minmax) ||
+ (table->proc_handler == proc_dointvec_jiffies) ||
+ (table->proc_handler == proc_dointvec_userhz_jiffies) ||
+ (table->proc_handler == proc_dointvec_ms_jiffies) ||
+ (table->proc_handler == proc_doulongvec_minmax) ||
+ (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
+ if (!table->data)
+ err |= sysctl_err(path, table, "No data");
+ if (!table->maxlen)
+ err |= sysctl_err(path, table, "No maxlen");
+ else
+ err |= sysctl_check_table_array(path, table);
+ }
+ if (!table->proc_handler)
+ err |= sysctl_err(path, table, "No proc_handler");
+
+ if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode)
+ err |= sysctl_err(path, table, "bogus .mode 0%o",
+ table->mode);
+ return err;
+}
+
static int sysctl_check_table(const char *path, struct ctl_table *table)
{
int err = 0;
@@ -1163,6 +1254,43 @@ static int sysctl_check_table(const char *path, struct ctl_table *table)
return err;
}
+static struct ctl_table_header *new_links_single(struct ctl_dir *dir, struct ctl_table *table,
+ struct ctl_table_root *link_root)
+{
+ struct ctl_table *link_table;
+ struct ctl_table_header *links;
+ struct ctl_node *node;
+ char *link_name;
+ int name_bytes = 0;
+
+ name_bytes += strlen(table->procname) + 1;
+
+ links = kzalloc(sizeof(struct ctl_table_header) +
+ sizeof(struct ctl_node) +
+ sizeof(struct ctl_table)*2 +
+ name_bytes,
+ GFP_KERNEL);
+
+ if (!links)
+ return NULL;
+
+ node = (struct ctl_node *)(links + 1);
+ link_table = (struct ctl_table *)(node + 1);
+ link_name = (char *)&link_table[2];
+
+ int len = strlen(table->procname) + 1;
+
+ memcpy(link_name, table->procname, len);
+ link_table->procname = link_name;
+ link_table->mode = S_IFLNK|S_IRWXUGO;
+ link_table->data = link_root;
+ link_name += len;
+
+ init_header_single(links, dir->header.root, dir->header.set, node, link_table);
+ links->nreg = 1;
+
+ return links;
+}
static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
struct ctl_table_root *link_root)
{
@@ -1206,6 +1334,27 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
return links;
}
+static bool get_links_single(struct ctl_dir *dir,
+ struct ctl_table *table, struct ctl_table_root *link_root)
+{
+ struct ctl_table_header *head;
+ struct ctl_table *link;
+
+ /* Is there link available for table? */
+ const char *procname = table->procname;
+
+ link = find_entry(&head, dir, procname, strlen(procname));
+ if (!link)
+ return false;
+ if ((S_ISDIR(link->mode) && S_ISDIR(table->mode)) ||
+ (S_ISLNK(link->mode) && (link->data == link_root))) {
+ head->nreg++;
+ return true;
+ }
+
+ return false;
+}
+
static bool get_links(struct ctl_dir *dir,
struct ctl_table *table, struct ctl_table_root *link_root)
{
@@ -1234,6 +1383,47 @@ static bool get_links(struct ctl_dir *dir,
return true;
}
+static int insert_links_single(struct ctl_table_header *head)
+{
+ struct ctl_table_set *root_set = &sysctl_table_root.default_set;
+ struct ctl_dir *core_parent = NULL;
+ struct ctl_table_header *links;
+ int err;
+
+ if (head->set == root_set)
+ return 0;
+
+ core_parent = xlate_dir(root_set, head->parent);
+ if (IS_ERR(core_parent))
+ return 0;
+
+ if (get_links_single(core_parent, head->ctl_table, head->root))
+ return 0;
+
+ core_parent->header.nreg++;
+ spin_unlock(&sysctl_lock);
+
+ links = new_links_single(core_parent, head->ctl_table, head->root);
+
+ spin_lock(&sysctl_lock);
+ err = -ENOMEM;
+ if (!links)
+ goto out;
+
+ err = 0;
+ if (get_links_single(core_parent, head->ctl_table, head->root)) {
+ kfree(links);
+ goto out;
+ }
+
+ err = insert_header_single(core_parent, links);
+ if (err)
+ kfree(links);
+out:
+ drop_sysctl_table(&core_parent->header);
+ return err;
+}
+
static int insert_links(struct ctl_table_header *head)
{
struct ctl_table_set *root_set = &sysctl_table_root.default_set;
@@ -1401,6 +1591,132 @@ struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *tab
}
EXPORT_SYMBOL(register_sysctl);
+/**
+ * __register_sysctl_table_single - register a leaf sysctl table
+ * @set: Sysctl tree to register on
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure
+ *
+ * Register extraly one sysctl table. @table should be a filled in extraly one
+ * ctl_table. If ctl_table which need to register have child or is not single,
+ * we should use register_sysctl_init or register_sysctl instead of
+ * register_sysctl_single.
+ *
+ * The members of the &struct ctl_table structure are used as follows:
+ *
+ * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
+ * enter a sysctl file
+ *
+ * data - a pointer to data for use by proc_handler
+ *
+ * maxlen - the maximum size in bytes of the data
+ *
+ * mode - the file permissions for the /proc/sys file
+ *
+ * child - must be %NULL.
+ *
+ * proc_handler - the text handler routine (described below)
+ *
+ * extra1, extra2 - extra pointers usable by the proc handler routines
+ *
+ * Leaf nodes in the sysctl tree will be represented by a single file
+ * under /proc; non-leaf nodes will be represented by directories.
+ *
+ * There must be a proc_handler routine for any terminal nodes.
+ * Several default handlers are available to cover common cases -
+ *
+ * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
+ * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
+ * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
+ *
+ * It is the handler's job to read the input buffer from user memory
+ * and process it. The handler should return 0 on success.
+ *
+ * This routine returns %NULL on a failure to register, and a pointer
+ * to the table header on success.
+ */
+struct ctl_table_header *__register_sysctl_table_single(
+ struct ctl_table_set *set,
+ const char *path, struct ctl_table *table)
+{
+ struct ctl_table_root *root = set->dir.header.root;
+ struct ctl_table_header *header;
+ const char *name, *nextname;
+ struct ctl_dir *dir;
+ struct ctl_node *node;
+
+ header = kzalloc(sizeof(struct ctl_table_header) +
+ sizeof(struct ctl_node), GFP_KERNEL);
+ if (!header)
+ return NULL;
+
+ node = (struct ctl_node *)(header + 1);
+ init_header_single(header, root, set, node, table);
+ if (sysctl_check_table_single(path, table))
+ goto fail;
+
+ spin_lock(&sysctl_lock);
+ dir = &set->dir;
+ /* Reference moved down the diretory tree get_subdir */
+ dir->header.nreg++;
+ spin_unlock(&sysctl_lock);
+
+ /* Find the directory for the ctl_table */
+ for (name = path; name; name = nextname) {
+ int namelen;
+
+ nextname = strchr(name, '/');
+ if (nextname) {
+ namelen = nextname - name;
+ nextname++;
+ } else {
+ namelen = strlen(name);
+ }
+ if (namelen == 0)
+ continue;
+
+ dir = get_subdir(dir, name, namelen);
+ if (IS_ERR(dir))
+ goto fail;
+ }
+
+ spin_lock(&sysctl_lock);
+ if (insert_header_single(dir, header))
+ goto fail_put_dir_locked;
+
+ drop_sysctl_table(&dir->header);
+ spin_unlock(&sysctl_lock);
+
+ return header;
+
+fail_put_dir_locked:
+ drop_sysctl_table(&dir->header);
+ spin_unlock(&sysctl_lock);
+fail:
+ kfree(header);
+ dump_stack();
+ return NULL;
+}
+
+/**
+ * __register_sysctl_single - register extraly one sysctl table
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the table structure
+ *
+ * Register extraly one sysctl table. @table should be a filled in extraly one
+ * ctl_table. If ctl_table which need to register have child or is not single,
+ * we should use register_sysctl_init or register_sysctl instead of
+ * register_sysctl_single.
+ *
+ * See __register_sysctl_table_single for more details.
+ */
+struct ctl_table_header *__register_sysctl_single(const char *path, struct ctl_table *table)
+{
+ return __register_sysctl_table_single(&sysctl_table_root.default_set,
+ path, table);
+}
+EXPORT_SYMBOL(__register_sysctl_single);
+
/**
* __register_sysctl_init() - register sysctl table to path
* @path: path name for sysctl base
@@ -1655,6 +1971,36 @@ int __register_sysctl_base(struct ctl_table *base_table)
return 0;
}
+static void put_links_single(struct ctl_table_header *header)
+{
+ struct ctl_table_set *root_set = &sysctl_table_root.default_set;
+ struct ctl_table_root *root = header->root;
+ struct ctl_dir *parent = header->parent;
+ struct ctl_dir *core_parent;
+
+ if (header->set == root_set)
+ return;
+
+ core_parent = xlate_dir(root_set, parent);
+ if (IS_ERR(core_parent))
+ return;
+
+ struct ctl_table_header *link_head;
+ struct ctl_table *link;
+ const char *name = header->ctl_table->procname;
+
+ link = find_entry(&link_head, core_parent, name, strlen(name));
+ if (link &&
+ ((S_ISDIR(link->mode) && S_ISDIR(header->ctl_table->mode)) ||
+ (S_ISLNK(link->mode) && (link->data == root)))) {
+ drop_sysctl_table(link_head);
+ } else {
+ pr_err("sysctl link missing during unregister: ");
+ sysctl_print_dir(parent);
+ pr_cont("%s\n", name);
+ }
+}
+
static void put_links(struct ctl_table_header *header)
{
struct ctl_table_set *root_set = &sysctl_table_root.default_set;
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 644fd53ad5f1..a7a5c3f25da9 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -235,6 +235,9 @@ extern int sysctl_init_bases(void);
extern void __register_sysctl_init(const char *path, struct ctl_table *table,
const char *table_name);
#define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table)
+extern struct ctl_table_header *__register_sysctl_single(const char *path,
+ struct ctl_table *table);
+#define register_sysctl_single(path, table) __register_sysctl_single(path, table)
extern struct ctl_table_header *register_sysctl_mount_point(const char *path);
void do_sysctl_args(void);
--
2.20.1
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/[email protected]/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 <[email protected]>
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/[email protected]
On Tue, Mar 01, 2022 at 07:53:40PM +0800, Meng Tang wrote:
> Sysctls are being moved out of kernel/sysctl.c and out to
> their own respective subsystems / users to help with easier
> maintance and avoid merge conflicts. But when we move just
> one entry and to its own new file the last entry for this
> new file must be empty, so we are essentialy bloating the
> kernel one extra empty entry per each newly moved sysctl.
>
> To help with this, this adds support for registering just
> one ctl_table, therefore not bloating the kernel when we
> move a single ctl_table to its own file.
>
> Suggested-by: Matthew Wilcox <[email protected]>
> Signed-off-by: Meng Tang <[email protected]>
Please extend the commit log to justify why we have to add
so much code, you mentioned it to me before, now just please
write that in the commit log.
Can you really not add helpers first so that these helpers
are used by both paths?
Luis
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: hexagon-randconfig-r045-20220301 (https://download.01.org/0day-ci/archive/20220301/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
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=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/proc/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> fs/proc/proc_sysctl.c:1281:6: warning: mixing declarations and code is a C99 extension [-Wdeclaration-after-statement]
int len = strlen(table->procname) + 1;
^
fs/proc/proc_sysctl.c:1638:26: warning: no previous prototype for function '__register_sysctl_table_single' [-Wmissing-prototypes]
struct ctl_table_header *__register_sysctl_table_single(
^
fs/proc/proc_sysctl.c:1638:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
struct ctl_table_header *__register_sysctl_table_single(
^
static
fs/proc/proc_sysctl.c:1988:27: warning: mixing declarations and code is a C99 extension [-Wdeclaration-after-statement]
struct ctl_table_header *link_head;
^
3 warnings generated.
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/[email protected]
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: nds32-allnoconfig (https://download.01.org/0day-ci/archive/20220301/[email protected]/config)
compiler: nds32le-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=nds32 SHELL=/bin/bash fs/proc/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
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/[email protected]