Commit 95d49778 authored by Joel Granados's avatar Joel Granados Committed by Luis Chamberlain
Browse files

sysctl: Add size to register_net_sysctl function 



This commit adds size to the register_net_sysctl indirection function to
facilitate the removal of the sentinel elements (last empty markers)
from the ctl_table arrays. Though we don't actually remove any sentinels
in this commit, register_net_sysctl* now has the capability of
forwarding table_size for when that happens.

We create a new function register_net_sysctl_sz with an extra size
argument. A macro replaces the existing register_net_sysctl. The size in
the macro is SIZE_MAX instead of ARRAY_SIZE to avoid compilation errors
while we systematically migrate to register_net_sysctl_sz. Will change
to ARRAY_SIZE in subsequent commits.

Care is taken to add table_size to the stopping criteria in such a way
that when we remove the empty sentinel element, it will continue
stopping in the last element of the ctl_table array.

Signed-off-by: default avatarJoel Granados <j.granados@samsung.com>
Suggested-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
parent 3bc269cf

include/net/net_namespace.h

+6 −4
Original line number Diff line number Diff line
@@ -469,15 +469,17 @@ void unregister_pernet_device(struct pernet_operations *); 


struct ctl_table;



#define register_net_sysctl(net, path, table)	\

	register_net_sysctl_sz(net, path, table, SIZE_MAX)

#ifdef CONFIG_SYSCTL

int net_sysctl_init(void);

struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,

					     struct ctl_table *table);

struct ctl_table_header *register_net_sysctl_sz(struct net *net, const char *path,

					     struct ctl_table *table, size_t table_size);

void unregister_net_sysctl_table(struct ctl_table_header *header);

#else

static inline int net_sysctl_init(void) { return 0; }

static inline struct ctl_table_header *register_net_sysctl(struct net *net,

	const char *path, struct ctl_table *table)

static inline struct ctl_table_header *register_net_sysctl_sz(struct net *net,

	const char *path, struct ctl_table *table, size_t table_size)

{

	return NULL;

}

net/sysctl_net.c

+13 −9
Original line number Diff line number Diff line
@@ -122,12 +122,13 @@ __init int net_sysctl_init(void) 
 *    allocated.

 */

static void ensure_safe_net_sysctl(struct net *net, const char *path,

				   struct ctl_table *table)

				   struct ctl_table *table, size_t table_size)

{

	struct ctl_table *ent;



	pr_debug("Registering net sysctl (net %p): %s\n", net, path);

	for (ent = table; ent->procname; ent++) {

	ent = table;

	for (size_t i = 0; i < table_size && ent->procname; ent++, i++) {

		unsigned long addr;

		const char *where;
@@ -160,21 +161,24 @@ static void ensure_safe_net_sysctl(struct net *net, const char *path, 
	}

}



struct ctl_table_header *register_net_sysctl(struct net *net,

	const char *path, struct ctl_table *table)

struct ctl_table_header *register_net_sysctl_sz(struct net *net,

						const char *path,

						struct ctl_table *table,

						size_t table_size)

{

	int count = 0;

	int count;

	struct ctl_table *entry;



	if (!net_eq(net, &init_net))

		ensure_safe_net_sysctl(net, path, table);

		ensure_safe_net_sysctl(net, path, table, table_size);



	for (entry = table; entry->procname; entry++)

		count++;

	entry = table;

	for (count = 0 ; count < table_size && entry->procname; entry++, count++)

		;



	return __register_sysctl_table(&net->sysctls, path, table, count);

}

EXPORT_SYMBOL_GPL(register_net_sysctl);

EXPORT_SYMBOL_GPL(register_net_sysctl_sz);



void unregister_net_sysctl_table(struct ctl_table_header *header)

{