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authorLinus Torvalds2023-08-29 17:39:15 -0700
committerLinus Torvalds2023-08-29 17:39:15 -0700
commitadfd671676c922bada16477eb68b5eb5f065addc (patch)
treefb98de5791b9bfabf25cf51fec20a1424efa32a0 /fs
parentdaa22f5a78c27412e88d31780c4a6262cda559cd (diff)
parent53f3811dfd5e39507ee3aaea1be09aabce8f9c98 (diff)
Merge tag 'sysctl-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull sysctl updates from Luis Chamberlain: "Long ago we set out to remove the kitchen sink on kernel/sysctl.c arrays and placings sysctls to their own sybsystem or file to help avoid merge conflicts. Matthew Wilcox pointed out though that if we're going to do that we might as well also *save* space while at it and try to remove the extra last sysctl entry added at the end of each array, a sentintel, instead of bloating the kernel by adding a new sentinel with each array moved. Doing that was not so trivial, and has required slowing down the moves of kernel/sysctl.c arrays and measuring the impact on size by each new move. The complex part of the effort to help reduce the size of each sysctl is being done by the patient work of el seƱor Don Joel Granados. A lot of this is truly painful code refactoring and testing and then trying to measure the savings of each move and removing the sentinels. Although Joel already has code which does most of this work, experience with sysctl moves in the past shows is we need to be careful due to the slew of odd build failures that are possible due to the amount of random Kconfig options sysctls use. To that end Joel's work is split by first addressing the major housekeeping needed to remove the sentinels, which is part of this merge request. The rest of the work to actually remove the sentinels will be done later in future kernel releases. The preliminary math is showing this will all help reduce the overall build time size of the kernel and run time memory consumed by the kernel by about ~64 bytes per array where we are able to remove each sentinel in the future. That also means there is no more bloating the kernel with the extra ~64 bytes per array moved as no new sentinels are created" * tag 'sysctl-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: sysctl: Use ctl_table_size as stopping criteria for list macro sysctl: SIZE_MAX->ARRAY_SIZE in register_net_sysctl vrf: Update to register_net_sysctl_sz networking: Update to register_net_sysctl_sz netfilter: Update to register_net_sysctl_sz ax.25: Update to register_net_sysctl_sz sysctl: Add size to register_net_sysctl function sysctl: Add size arg to __register_sysctl_init sysctl: Add size to register_sysctl sysctl: Add a size arg to __register_sysctl_table sysctl: Add size argument to init_header sysctl: Add ctl_table_size to ctl_table_header sysctl: Use ctl_table_header in list_for_each_table_entry sysctl: Prefer ctl_table_header in proc_sysctl
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/proc_sysctl.c90
1 files changed, 46 insertions, 44 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index bf06344a42cc..c88854df0b62 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -19,8 +19,9 @@
#include <linux/kmemleak.h>
#include "internal.h"
-#define list_for_each_table_entry(entry, table) \
- for ((entry) = (table); (entry)->procname; (entry)++)
+#define list_for_each_table_entry(entry, header) \
+ entry = header->ctl_table; \
+ for (size_t i = 0 ; i < header->ctl_table_size && entry->procname; ++i, entry++)
static const struct dentry_operations proc_sys_dentry_operations;
static const struct file_operations proc_sys_file_operations;
@@ -43,7 +44,7 @@ static struct ctl_table sysctl_mount_point[] = {
*/
struct ctl_table_header *register_sysctl_mount_point(const char *path)
{
- return register_sysctl(path, sysctl_mount_point);
+ return register_sysctl_sz(path, sysctl_mount_point, 0);
}
EXPORT_SYMBOL(register_sysctl_mount_point);
@@ -188,9 +189,10 @@ static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry)
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)
+ struct ctl_node *node, struct ctl_table *table, size_t table_size)
{
head->ctl_table = table;
+ head->ctl_table_size = table_size;
head->ctl_table_arg = table;
head->used = 0;
head->count = 1;
@@ -204,7 +206,7 @@ static void init_header(struct ctl_table_header *head,
if (node) {
struct ctl_table *entry;
- list_for_each_table_entry(entry, table) {
+ list_for_each_table_entry(entry, head) {
node->header = head;
node++;
}
@@ -215,7 +217,7 @@ static void erase_header(struct ctl_table_header *head)
{
struct ctl_table *entry;
- list_for_each_table_entry(entry, head->ctl_table)
+ list_for_each_table_entry(entry, head)
erase_entry(head, entry);
}
@@ -242,7 +244,7 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
err = insert_links(header);
if (err)
goto fail_links;
- list_for_each_table_entry(entry, header->ctl_table) {
+ list_for_each_table_entry(entry, header) {
err = insert_entry(header, entry);
if (err)
goto fail;
@@ -973,7 +975,7 @@ static struct ctl_dir *new_dir(struct ctl_table_set *set,
memcpy(new_name, name, namelen);
table[0].procname = new_name;
table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
- init_header(&new->header, set->dir.header.root, set, node, table);
+ init_header(&new->header, set->dir.header.root, set, node, table, 1);
return new;
}
@@ -1125,11 +1127,11 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
return err;
}
-static int sysctl_check_table(const char *path, struct ctl_table *table)
+static int sysctl_check_table(const char *path, struct ctl_table_header *header)
{
struct ctl_table *entry;
int err = 0;
- list_for_each_table_entry(entry, table) {
+ list_for_each_table_entry(entry, header) {
if ((entry->proc_handler == proc_dostring) ||
(entry->proc_handler == proc_dobool) ||
(entry->proc_handler == proc_dointvec) ||
@@ -1159,8 +1161,7 @@ static int sysctl_check_table(const char *path, struct ctl_table *table)
return err;
}
-static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
- struct ctl_table_root *link_root)
+static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_header *head)
{
struct ctl_table *link_table, *entry, *link;
struct ctl_table_header *links;
@@ -1170,7 +1171,7 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
name_bytes = 0;
nr_entries = 0;
- list_for_each_table_entry(entry, table) {
+ list_for_each_table_entry(entry, head) {
nr_entries++;
name_bytes += strlen(entry->procname) + 1;
}
@@ -1189,31 +1190,33 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
link_name = (char *)&link_table[nr_entries + 1];
link = link_table;
- list_for_each_table_entry(entry, table) {
+ list_for_each_table_entry(entry, head) {
int len = strlen(entry->procname) + 1;
memcpy(link_name, entry->procname, len);
link->procname = link_name;
link->mode = S_IFLNK|S_IRWXUGO;
- link->data = link_root;
+ link->data = head->root;
link_name += len;
link++;
}
- init_header(links, dir->header.root, dir->header.set, node, link_table);
+ init_header(links, dir->header.root, dir->header.set, node, link_table,
+ head->ctl_table_size);
links->nreg = nr_entries;
return links;
}
static bool get_links(struct ctl_dir *dir,
- struct ctl_table *table, struct ctl_table_root *link_root)
+ struct ctl_table_header *header,
+ struct ctl_table_root *link_root)
{
- struct ctl_table_header *head;
+ struct ctl_table_header *tmp_head;
struct ctl_table *entry, *link;
/* Are there links available for every entry in table? */
- list_for_each_table_entry(entry, table) {
+ list_for_each_table_entry(entry, header) {
const char *procname = entry->procname;
- link = find_entry(&head, dir, procname, strlen(procname));
+ link = find_entry(&tmp_head, dir, procname, strlen(procname));
if (!link)
return false;
if (S_ISDIR(link->mode) && S_ISDIR(entry->mode))
@@ -1224,10 +1227,10 @@ static bool get_links(struct ctl_dir *dir,
}
/* The checks passed. Increase the registration count on the links */
- list_for_each_table_entry(entry, table) {
+ list_for_each_table_entry(entry, header) {
const char *procname = entry->procname;
- link = find_entry(&head, dir, procname, strlen(procname));
- head->nreg++;
+ link = find_entry(&tmp_head, dir, procname, strlen(procname));
+ tmp_head->nreg++;
}
return true;
}
@@ -1246,13 +1249,13 @@ static int insert_links(struct ctl_table_header *head)
if (IS_ERR(core_parent))
return 0;
- if (get_links(core_parent, head->ctl_table, head->root))
+ if (get_links(core_parent, head, head->root))
return 0;
core_parent->header.nreg++;
spin_unlock(&sysctl_lock);
- links = new_links(core_parent, head->ctl_table, head->root);
+ links = new_links(core_parent, head);
spin_lock(&sysctl_lock);
err = -ENOMEM;
@@ -1260,7 +1263,7 @@ static int insert_links(struct ctl_table_header *head)
goto out;
err = 0;
- if (get_links(core_parent, head->ctl_table, head->root)) {
+ if (get_links(core_parent, head, head->root)) {
kfree(links);
goto out;
}
@@ -1310,6 +1313,7 @@ static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path)
* should not be free'd after registration. So it should not be
* used on stack. It can either be a global or dynamically allocated
* by the caller and free'd later after sysctl unregistration.
+ * @table_size : The number of elements in table
*
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
* array. A completely 0 filled entry terminates the table.
@@ -1352,26 +1356,21 @@ static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path)
*/
struct ctl_table_header *__register_sysctl_table(
struct ctl_table_set *set,
- const char *path, struct ctl_table *table)
+ const char *path, struct ctl_table *table, size_t table_size)
{
struct ctl_table_root *root = set->dir.header.root;
struct ctl_table_header *header;
struct ctl_dir *dir;
- struct ctl_table *entry;
struct ctl_node *node;
- int nr_entries = 0;
-
- list_for_each_table_entry(entry, table)
- nr_entries++;
header = kzalloc(sizeof(struct ctl_table_header) +
- sizeof(struct ctl_node)*nr_entries, GFP_KERNEL_ACCOUNT);
+ sizeof(struct ctl_node)*table_size, GFP_KERNEL_ACCOUNT);
if (!header)
return NULL;
node = (struct ctl_node *)(header + 1);
- init_header(header, root, set, node, table);
- if (sysctl_check_table(path, table))
+ init_header(header, root, set, node, table, table_size);
+ if (sysctl_check_table(path, header))
goto fail;
spin_lock(&sysctl_lock);
@@ -1401,7 +1400,7 @@ fail:
}
/**
- * register_sysctl - register a sysctl table
+ * register_sysctl_sz - register a sysctl table
* @path: The path to the directory the sysctl table is in. If the path
* doesn't exist we will create it for you.
* @table: the table structure. The calller must ensure the life of the @table
@@ -1411,18 +1410,20 @@ fail:
* to call unregister_sysctl_table() and can instead use something like
* register_sysctl_init() which does not care for the result of the syctl
* registration.
+ * @table_size: The number of elements in table.
*
* Register a sysctl table. @table should be a filled in ctl_table
* array. A completely 0 filled entry terminates the table.
*
* See __register_sysctl_table for more details.
*/
-struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
+struct ctl_table_header *register_sysctl_sz(const char *path, struct ctl_table *table,
+ size_t table_size)
{
return __register_sysctl_table(&sysctl_table_root.default_set,
- path, table);
+ path, table, table_size);
}
-EXPORT_SYMBOL(register_sysctl);
+EXPORT_SYMBOL(register_sysctl_sz);
/**
* __register_sysctl_init() - register sysctl table to path
@@ -1433,6 +1434,7 @@ EXPORT_SYMBOL(register_sysctl);
* lifetime use of the sysctl.
* @table_name: The name of sysctl table, only used for log printing when
* registration fails
+ * @table_size: The number of elements in table
*
* The sysctl interface is used by userspace to query or modify at runtime
* a predefined value set on a variable. These variables however have default
@@ -1445,12 +1447,12 @@ EXPORT_SYMBOL(register_sysctl);
* Context: if your base directory does not exist it will be created for you.
*/
void __init __register_sysctl_init(const char *path, struct ctl_table *table,
- const char *table_name)
+ const char *table_name, size_t table_size)
{
- struct ctl_table_header *hdr = register_sysctl(path, table);
+ struct ctl_table_header *hdr = register_sysctl_sz(path, table, table_size);
if (unlikely(!hdr)) {
- pr_err("failed when register_sysctl %s to %s\n", table_name, path);
+ pr_err("failed when register_sysctl_sz %s to %s\n", table_name, path);
return;
}
kmemleak_not_leak(hdr);
@@ -1471,7 +1473,7 @@ static void put_links(struct ctl_table_header *header)
if (IS_ERR(core_parent))
return;
- list_for_each_table_entry(entry, header->ctl_table) {
+ list_for_each_table_entry(entry, header) {
struct ctl_table_header *link_head;
struct ctl_table *link;
const char *name = entry->procname;
@@ -1535,7 +1537,7 @@ void setup_sysctl_set(struct ctl_table_set *set,
{
memset(set, 0, sizeof(*set));
set->is_seen = is_seen;
- init_header(&set->dir.header, root, set, NULL, root_table);
+ init_header(&set->dir.header, root, set, NULL, root_table, 1);
}
void retire_sysctl_set(struct ctl_table_set *set)