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path: root/fs/proc/proc_sysctl.c
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Diffstat (limited to 'fs/proc/proc_sysctl.c')
-rw-r--r--fs/proc/proc_sysctl.c113
1 files changed, 60 insertions, 53 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index d11ebc055ce0..27a283d85a6e 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -17,6 +17,7 @@
#include <linux/bpf-cgroup.h>
#include <linux/mount.h>
#include <linux/kmemleak.h>
+#include <linux/lockdep.h>
#include "internal.h"
#define list_for_each_table_entry(entry, header) \
@@ -33,7 +34,7 @@ static const struct inode_operations proc_sys_dir_operations;
* Support for permanently empty directories.
* Must be non-empty to avoid sharing an address with other tables.
*/
-static struct ctl_table sysctl_mount_point[] = {
+static const struct ctl_table sysctl_mount_point[] = {
{ }
};
@@ -67,7 +68,7 @@ void proc_sys_poll_notify(struct ctl_table_poll *poll)
wake_up_interruptible(&poll->wait);
}
-static struct ctl_table root_table[] = {
+static const struct ctl_table root_table[] = {
{
.procname = "",
.mode = S_IFDIR|S_IRUGO|S_IXUGO,
@@ -88,7 +89,7 @@ static DEFINE_SPINLOCK(sysctl_lock);
static void drop_sysctl_table(struct ctl_table_header *header);
static int sysctl_follow_link(struct ctl_table_header **phead,
- struct ctl_table **pentry);
+ const struct ctl_table **pentry);
static int insert_links(struct ctl_table_header *head);
static void put_links(struct ctl_table_header *header);
@@ -109,14 +110,15 @@ static int namecmp(const char *name1, int len1, const char *name2, int len2)
return cmp;
}
-/* Called under sysctl_lock */
-static struct ctl_table *find_entry(struct ctl_table_header **phead,
+static const struct ctl_table *find_entry(struct ctl_table_header **phead,
struct ctl_dir *dir, const char *name, int namelen)
{
struct ctl_table_header *head;
- struct ctl_table *entry;
+ const struct ctl_table *entry;
struct rb_node *node = dir->root.rb_node;
+ lockdep_assert_held(&sysctl_lock);
+
while (node)
{
struct ctl_node *ctl_node;
@@ -141,7 +143,7 @@ static struct ctl_table *find_entry(struct ctl_table_header **phead,
return NULL;
}
-static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry)
+static int insert_entry(struct ctl_table_header *head, const struct ctl_table *entry)
{
struct rb_node *node = &head->node[entry - head->ctl_table].node;
struct rb_node **p = &head->parent->root.rb_node;
@@ -151,7 +153,7 @@ static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry)
while (*p) {
struct ctl_table_header *parent_head;
- struct ctl_table *parent_entry;
+ const struct ctl_table *parent_entry;
struct ctl_node *parent_node;
const char *parent_name;
int cmp;
@@ -180,7 +182,7 @@ static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry)
return 0;
}
-static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry)
+static void erase_entry(struct ctl_table_header *head, const struct ctl_table *entry)
{
struct rb_node *node = &head->node[entry - head->ctl_table].node;
@@ -189,7 +191,7 @@ 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, size_t table_size)
+ struct ctl_node *node, const struct ctl_table *table, size_t table_size)
{
head->ctl_table = table;
head->ctl_table_size = table_size;
@@ -204,7 +206,7 @@ static void init_header(struct ctl_table_header *head,
head->node = node;
INIT_HLIST_HEAD(&head->inodes);
if (node) {
- struct ctl_table *entry;
+ const struct ctl_table *entry;
list_for_each_table_entry(entry, head) {
node->header = head;
@@ -217,7 +219,7 @@ static void init_header(struct ctl_table_header *head,
static void erase_header(struct ctl_table_header *head)
{
- struct ctl_table *entry;
+ const struct ctl_table *entry;
list_for_each_table_entry(entry, head)
erase_entry(head, entry);
@@ -225,7 +227,7 @@ static void erase_header(struct ctl_table_header *head)
static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
{
- struct ctl_table *entry;
+ const struct ctl_table *entry;
struct ctl_table_header *dir_h = &dir->header;
int err;
@@ -263,18 +265,20 @@ fail_links:
return err;
}
-/* called under sysctl_lock */
static int use_table(struct ctl_table_header *p)
{
+ lockdep_assert_held(&sysctl_lock);
+
if (unlikely(p->unregistering))
return 0;
p->used++;
return 1;
}
-/* called under sysctl_lock */
static void unuse_table(struct ctl_table_header *p)
{
+ lockdep_assert_held(&sysctl_lock);
+
if (!--p->used)
if (unlikely(p->unregistering))
complete(p->unregistering);
@@ -285,9 +289,11 @@ static void proc_sys_invalidate_dcache(struct ctl_table_header *head)
proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock);
}
-/* called under sysctl_lock, will reacquire if has to wait */
static void start_unregistering(struct ctl_table_header *p)
{
+ /* will reacquire if has to wait */
+ lockdep_assert_held(&sysctl_lock);
+
/*
* if p->used is 0, nobody will ever touch that entry again;
* we'll eliminate all paths to it before dropping sysctl_lock
@@ -344,12 +350,12 @@ lookup_header_set(struct ctl_table_root *root)
return set;
}
-static struct ctl_table *lookup_entry(struct ctl_table_header **phead,
- struct ctl_dir *dir,
- const char *name, int namelen)
+static const struct ctl_table *lookup_entry(struct ctl_table_header **phead,
+ struct ctl_dir *dir,
+ const char *name, int namelen)
{
struct ctl_table_header *head;
- struct ctl_table *entry;
+ const struct ctl_table *entry;
spin_lock(&sysctl_lock);
entry = find_entry(&head, dir, name, namelen);
@@ -374,10 +380,10 @@ static struct ctl_node *first_usable_entry(struct rb_node *node)
}
static void first_entry(struct ctl_dir *dir,
- struct ctl_table_header **phead, struct ctl_table **pentry)
+ struct ctl_table_header **phead, const struct ctl_table **pentry)
{
struct ctl_table_header *head = NULL;
- struct ctl_table *entry = NULL;
+ const struct ctl_table *entry = NULL;
struct ctl_node *ctl_node;
spin_lock(&sysctl_lock);
@@ -391,10 +397,10 @@ static void first_entry(struct ctl_dir *dir,
*pentry = entry;
}
-static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry)
+static void next_entry(struct ctl_table_header **phead, const struct ctl_table **pentry)
{
struct ctl_table_header *head = *phead;
- struct ctl_table *entry = *pentry;
+ const struct ctl_table *entry = *pentry;
struct ctl_node *ctl_node = &head->node[entry - head->ctl_table];
spin_lock(&sysctl_lock);
@@ -427,7 +433,7 @@ static int test_perm(int mode, int op)
return -EACCES;
}
-static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op)
+static int sysctl_perm(struct ctl_table_header *head, const struct ctl_table *table, int op)
{
struct ctl_table_root *root = head->root;
int mode;
@@ -441,7 +447,7 @@ static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, i
}
static struct inode *proc_sys_make_inode(struct super_block *sb,
- struct ctl_table_header *head, struct ctl_table *table)
+ struct ctl_table_header *head, const struct ctl_table *table)
{
struct ctl_table_root *root = head->root;
struct inode *inode;
@@ -512,7 +518,7 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
struct ctl_table_header *head = grab_header(dir);
struct ctl_table_header *h = NULL;
const struct qstr *name = &dentry->d_name;
- struct ctl_table *p;
+ const struct ctl_table *p;
struct inode *inode;
struct dentry *err = ERR_PTR(-ENOENT);
struct ctl_dir *ctl_dir;
@@ -550,7 +556,7 @@ static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter,
{
struct inode *inode = file_inode(iocb->ki_filp);
struct ctl_table_header *head = grab_header(inode);
- struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+ const struct ctl_table *table = PROC_I(inode)->sysctl_entry;
size_t count = iov_iter_count(iter);
char *kbuf;
ssize_t error;
@@ -624,7 +630,7 @@ static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter)
static int proc_sys_open(struct inode *inode, struct file *filp)
{
struct ctl_table_header *head = grab_header(inode);
- struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+ const struct ctl_table *table = PROC_I(inode)->sysctl_entry;
/* sysctl was unregistered */
if (IS_ERR(head))
@@ -642,7 +648,7 @@ static __poll_t proc_sys_poll(struct file *filp, poll_table *wait)
{
struct inode *inode = file_inode(filp);
struct ctl_table_header *head = grab_header(inode);
- struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+ const struct ctl_table *table = PROC_I(inode)->sysctl_entry;
__poll_t ret = DEFAULT_POLLMASK;
unsigned long event;
@@ -673,7 +679,7 @@ out:
static bool proc_sys_fill_cache(struct file *file,
struct dir_context *ctx,
struct ctl_table_header *head,
- struct ctl_table *table)
+ const struct ctl_table *table)
{
struct dentry *child, *dir = file->f_path.dentry;
struct inode *inode;
@@ -698,11 +704,11 @@ static bool proc_sys_fill_cache(struct file *file,
res = d_splice_alias(inode, child);
d_lookup_done(child);
if (unlikely(res)) {
- if (IS_ERR(res)) {
- dput(child);
- return false;
- }
dput(child);
+
+ if (IS_ERR(res))
+ return false;
+
child = res;
}
}
@@ -717,7 +723,7 @@ static bool proc_sys_fill_cache(struct file *file,
static bool proc_sys_link_fill_cache(struct file *file,
struct dir_context *ctx,
struct ctl_table_header *head,
- struct ctl_table *table)
+ const struct ctl_table *table)
{
bool ret = true;
@@ -735,7 +741,7 @@ out:
return ret;
}
-static int scan(struct ctl_table_header *head, struct ctl_table *table,
+static int scan(struct ctl_table_header *head, const struct ctl_table *table,
unsigned long *pos, struct file *file,
struct dir_context *ctx)
{
@@ -759,7 +765,7 @@ static int proc_sys_readdir(struct file *file, struct dir_context *ctx)
{
struct ctl_table_header *head = grab_header(file_inode(file));
struct ctl_table_header *h = NULL;
- struct ctl_table *entry;
+ const struct ctl_table *entry;
struct ctl_dir *ctl_dir;
unsigned long pos;
@@ -792,7 +798,7 @@ static int proc_sys_permission(struct mnt_idmap *idmap,
* are _NOT_ writeable, capabilities or not.
*/
struct ctl_table_header *head;
- struct ctl_table *table;
+ const struct ctl_table *table;
int error;
/* Executable files are not allowed under /proc/sys/ */
@@ -836,7 +842,7 @@ static int proc_sys_getattr(struct mnt_idmap *idmap,
{
struct inode *inode = d_inode(path->dentry);
struct ctl_table_header *head = grab_header(inode);
- struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+ const struct ctl_table *table = PROC_I(inode)->sysctl_entry;
if (IS_ERR(head))
return PTR_ERR(head);
@@ -935,7 +941,7 @@ static struct ctl_dir *find_subdir(struct ctl_dir *dir,
const char *name, int namelen)
{
struct ctl_table_header *head;
- struct ctl_table *entry;
+ const struct ctl_table *entry;
entry = find_entry(&head, dir, name, namelen);
if (!entry)
@@ -1046,12 +1052,12 @@ static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir)
}
static int sysctl_follow_link(struct ctl_table_header **phead,
- struct ctl_table **pentry)
+ const struct ctl_table **pentry)
{
struct ctl_table_header *head;
+ const struct ctl_table *entry;
struct ctl_table_root *root;
struct ctl_table_set *set;
- struct ctl_table *entry;
struct ctl_dir *dir;
int ret;
@@ -1078,7 +1084,7 @@ static int sysctl_follow_link(struct ctl_table_header **phead,
return ret;
}
-static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
+static int sysctl_err(const char *path, const struct ctl_table *table, char *fmt, ...)
{
struct va_format vaf;
va_list args;
@@ -1094,7 +1100,7 @@ static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
return -EINVAL;
}
-static int sysctl_check_table_array(const char *path, struct ctl_table *table)
+static int sysctl_check_table_array(const char *path, const struct ctl_table *table)
{
unsigned int extra;
int err = 0;
@@ -1133,7 +1139,7 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
static int sysctl_check_table(const char *path, struct ctl_table_header *header)
{
- struct ctl_table *entry;
+ const struct ctl_table *entry;
int err = 0;
list_for_each_table_entry(entry, header) {
if (!entry->procname)
@@ -1169,8 +1175,9 @@ static int sysctl_check_table(const char *path, struct ctl_table_header *header)
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 *link_table, *link;
struct ctl_table_header *links;
+ const struct ctl_table *entry;
struct ctl_node *node;
char *link_name;
int name_bytes;
@@ -1215,7 +1222,7 @@ static bool get_links(struct ctl_dir *dir,
struct ctl_table_root *link_root)
{
struct ctl_table_header *tmp_head;
- struct ctl_table *entry, *link;
+ const struct ctl_table *entry, *link;
if (header->ctl_table_size == 0 ||
sysctl_is_perm_empty_ctl_header(header))
@@ -1358,7 +1365,7 @@ 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, size_t table_size)
+ const char *path, const struct ctl_table *table, size_t table_size)
{
struct ctl_table_root *root = set->dir.header.root;
struct ctl_table_header *header;
@@ -1419,7 +1426,7 @@ fail:
*
* See __register_sysctl_table for more details.
*/
-struct ctl_table_header *register_sysctl_sz(const char *path, struct ctl_table *table,
+struct ctl_table_header *register_sysctl_sz(const char *path, const struct ctl_table *table,
size_t table_size)
{
return __register_sysctl_table(&sysctl_table_root.default_set,
@@ -1448,7 +1455,7 @@ EXPORT_SYMBOL(register_sysctl_sz);
*
* 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,
+void __init __register_sysctl_init(const char *path, const struct ctl_table *table,
const char *table_name, size_t table_size)
{
struct ctl_table_header *hdr = register_sysctl_sz(path, table, table_size);
@@ -1466,7 +1473,7 @@ static void put_links(struct ctl_table_header *header)
struct ctl_table_root *root = header->root;
struct ctl_dir *parent = header->parent;
struct ctl_dir *core_parent;
- struct ctl_table *entry;
+ const struct ctl_table *entry;
if (header->set == root_set)
return;
@@ -1477,7 +1484,7 @@ static void put_links(struct ctl_table_header *header)
list_for_each_table_entry(entry, header) {
struct ctl_table_header *link_head;
- struct ctl_table *link;
+ const struct ctl_table *link;
const char *name = entry->procname;
link = find_entry(&link_head, core_parent, name, strlen(name));