[PATCH v2 14/18] sysctl: move internal interfaces to const struct ctl_table

From: Thomas Weißschuh
Date: Mon Dec 04 2023 - 02:53:47 EST

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

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 9a8f32f21ff5..36d6bf581688 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -101,7 +101,7 @@ 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 a398cc77637f..e7fd1680d479 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -86,7 +86,7 @@ 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);

@@ -108,11 +108,11 @@ 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)
@@ -139,7 +139,7 @@ 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;
@@ -149,7 +149,7 @@ 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;
@@ -178,7 +178,7 @@ 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;

@@ -187,7 +187,7 @@ 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;
@@ -202,7 +202,7 @@ 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;
@@ -213,7 +213,7 @@ 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);
@@ -221,7 +221,7 @@ 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;

@@ -341,12 +341,12 @@ 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);
@@ -371,10 +371,10 @@ 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);
@@ -388,10 +388,10 @@ 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);
@@ -424,7 +424,7 @@ 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;
@@ -438,7 +438,7 @@ 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;
@@ -511,7 +511,7 @@ 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;
@@ -554,7 +554,7 @@ 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;
@@ -628,7 +628,7 @@ 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))
@@ -646,7 +646,7 @@ 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;

@@ -677,7 +677,7 @@ 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;
@@ -726,7 +726,7 @@ 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;

@@ -744,7 +744,7 @@ 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)
{
@@ -768,7 +768,7 @@ 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;

@@ -801,7 +801,7 @@ 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/ */
@@ -845,7 +845,7 @@ 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);
@@ -944,7 +944,7 @@ 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)
@@ -1055,12 +1055,12 @@ 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;

@@ -1087,7 +1087,7 @@ 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;
@@ -1103,7 +1103,7 @@ 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)
{
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->proc_handler == proc_dostring) ||
@@ -1162,8 +1162,9 @@ 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 nr_entries, 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;

/* Are there links available for every entry in table? */
list_for_each_table_entry(entry, header) {
@@ -1463,7 +1464,7 @@ 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;
@@ -1474,7 +1475,7 @@ 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 061ea65104be..2f4d577f2e93 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;

--
2.43.0

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