[PATCH net-next 01/13] net: core: netlink: add helper refcount dec and lock function
From: Vlad Buslov <hidden>
Date: 2018-09-06 12:33:25
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Rtnl lock is encapsulated in netlink and cannot be accessed by other modules directly. This means that reference counted objects that rely on rtnl lock cannot use it with refcounter helper function that atomically releases decrements reference and obtains mutex. This patch implements simple wrapper function around refcount_dec_and_lock that obtains rtnl lock if reference counter value reached 0. Signed-off-by: Vlad Buslov <redacted> Acked-by: Jiri Pirko <redacted> --- include/linux/rtnetlink.h | 1 + net/core/rtnetlink.c | 6 ++++++ 2 files changed, 7 insertions(+)
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 5225832bd6ff..dffbf665c086 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h@@ -34,6 +34,7 @@ extern void rtnl_unlock(void); extern int rtnl_trylock(void); extern int rtnl_is_locked(void); extern int rtnl_lock_killable(void); +extern bool refcount_dec_and_rtnl_lock(refcount_t *r); extern wait_queue_head_t netdev_unregistering_wq; extern struct rw_semaphore pernet_ops_rwsem;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 60c928894a78..4ea0b1413076 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -130,6 +130,12 @@ int rtnl_is_locked(void) } EXPORT_SYMBOL(rtnl_is_locked); +bool refcount_dec_and_rtnl_lock(refcount_t *r) +{ + return refcount_dec_and_mutex_lock(r, &rtnl_mutex); +} +EXPORT_SYMBOL(refcount_dec_and_rtnl_lock); + #ifdef CONFIG_PROVE_LOCKING bool lockdep_rtnl_is_held(void) {
--
2.7.5