[PATCH 2/5] sysctl: move internal interfaces to const struct ctl_table

From: Thomas Weißschuh
Date: Mon Jul 29 2024 - 16:44:27 EST

Next message: Thomas Weißschuh: "[PATCH 3/5] sysctl: allow registration of const struct ctl_table"
Previous message: Thomas Weißschuh: "[PATCH 4/5] sysctl: make internal ctl_tables const"
In reply to: Thomas Weißschuh: "[PATCH 4/5] sysctl: make internal ctl_tables const"
Next in thread: Thomas Weißschuh: "[PATCH 3/5] sysctl: allow registration of const struct ctl_table"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

As a preparation to make all the core sysctl code work with const struct
ctl_table switch over the internal function to use the const variant.

Some pointers to "struct ctl_table" need to stay non-const as they are
newly allocated and modified before registration.

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
fs/proc/internal.h | 2 +-
fs/proc/proc_sysctl.c | 81 +++++++++++++++++++++++++-------------------------
include/linux/sysctl.h | 2 +-
3 files changed, 43 insertions(+), 42 deletions(-)

diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index a8a8576d8592..fcab5dd7ddb1 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -102,7 +102,7 @@ struct proc_inode {
union proc_op op;
struct proc_dir_entry *pde;
struct ctl_table_header *sysctl;
- struct ctl_table *sysctl_entry;
+ const struct ctl_table *sysctl_entry;
struct hlist_node sibling_inodes;
const struct proc_ns_operations *ns_ops;
struct inode vfs_inode;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 9553e77c9d31..fa8cf9bf2988 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -83,7 +83,7 @@ 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);

@@ -105,11 +105,11 @@ static int namecmp(const char *name1, int len1, const char *name2, int len2)
}

/* 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;

while (node)
@@ -136,7 +136,7 @@ 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;
@@ -146,7 +146,7 @@ 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;
@@ -175,7 +175,7 @@ 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;

@@ -184,7 +184,7 @@ 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;
@@ -199,7 +199,7 @@ 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;
@@ -212,7 +212,7 @@ 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);
@@ -220,7 +220,7 @@ 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;

@@ -339,12 +339,12 @@ 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);
@@ -369,10 +369,10 @@ 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);
@@ -386,10 +386,10 @@ 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);
@@ -422,7 +422,7 @@ 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;
@@ -436,7 +436,7 @@ 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;
@@ -507,7 +507,7 @@ 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;
@@ -545,7 +545,7 @@ 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;
@@ -619,7 +619,7 @@ 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))
@@ -637,7 +637,7 @@ 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;

@@ -668,7 +668,7 @@ static __poll_t proc_sys_poll(struct file *filp, poll_table *wait)
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;
@@ -712,7 +712,7 @@ 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;

@@ -730,7 +730,7 @@ static bool proc_sys_link_fill_cache(struct file *file,
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)
{
@@ -754,7 +754,7 @@ 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;

@@ -787,7 +787,7 @@ 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/ */
@@ -831,7 +831,7 @@ 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);
@@ -930,7 +930,7 @@ 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)
@@ -1041,12 +1041,12 @@ 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;

@@ -1073,7 +1073,7 @@ 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;
@@ -1089,7 +1089,7 @@ 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;
@@ -1128,7 +1128,7 @@ 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)
@@ -1164,8 +1164,9 @@ 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;
@@ -1210,7 +1211,7 @@ 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))
@@ -1461,7 +1462,7 @@ 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;
@@ -1472,7 +1473,7 @@ 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));
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index aa4c6d44aaa0..a473deaf5a91 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -162,7 +162,7 @@ struct ctl_node {
struct ctl_table_header {
union {
struct {
- struct ctl_table *ctl_table;
+ const struct ctl_table *ctl_table;
int ctl_table_size;
int used;
int count;

--
2.45.2

Next message: Thomas Weißschuh: "[PATCH 3/5] sysctl: allow registration of const struct ctl_table"
Previous message: Thomas Weißschuh: "[PATCH 4/5] sysctl: make internal ctl_tables const"
In reply to: Thomas Weißschuh: "[PATCH 4/5] sysctl: make internal ctl_tables const"
Next in thread: Thomas Weißschuh: "[PATCH 3/5] sysctl: allow registration of const struct ctl_table"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]