diff options
| author | David S. Miller <davem@davemloft.net> | 2023-12-18 02:05:45 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-12-18 02:05:45 +0000 |
| commit | 610a689d2a57af3e21993cb6d8c3e5f839a8c89e (patch) | |
| tree | 263284eb0373c4eb54f6573434bcb6b073b772fa | |
| parent | 54f4c2570a19186dfebd555b163084c1824cf1d6 (diff) | |
| parent | 174523479aae31b17c043de127c87ff2aef3d54e (diff) | |
Merge branch 'rtnl-rcu'
Pedro Tammela says:
====================
net: rtnl: introduce rcu_replace_pointer_rtnl
Introduce the rcu_replace_pointer_rtnl helper to lockdep check rtnl lock
rcu replacements, alongside the already existing helpers.
Patch 2 uses the new helper in the rtnl_unregister_* functions.
Originally this change was part of the P4TC series, as it's a recurrent
pattern there, but since it has a use case in mainline we are pushing it
separately.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/rtnetlink.h | 12 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 12 |
2 files changed, 15 insertions, 9 deletions
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 6a8543b34e2c..410529fca18b 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -79,6 +79,18 @@ static inline bool lockdep_rtnl_is_held(void) #define rtnl_dereference(p) \ rcu_dereference_protected(p, lockdep_rtnl_is_held()) +/** + * rcu_replace_pointer_rtnl - replace an RCU pointer under rtnl_lock, returning + * its old value + * @rp: RCU pointer, whose value is returned + * @p: regular pointer + * + * Perform a replacement under rtnl_lock, where @rp is an RCU-annotated + * pointer. The old value of @rp is returned, and @rp is set to @p + */ +#define rcu_replace_pointer_rtnl(rp, p) \ + rcu_replace_pointer(rp, p, lockdep_rtnl_is_held()) + static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev) { return rtnl_dereference(dev->ingress_queue); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 5e0ab4c08f72..94c4572512b8 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -342,8 +342,7 @@ int rtnl_unregister(int protocol, int msgtype) return -ENOENT; } - link = rtnl_dereference(tab[msgindex]); - RCU_INIT_POINTER(tab[msgindex], NULL); + link = rcu_replace_pointer_rtnl(tab[msgindex], NULL); rtnl_unlock(); kfree_rcu(link, rcu); @@ -368,18 +367,13 @@ void rtnl_unregister_all(int protocol) BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX); rtnl_lock(); - tab = rtnl_dereference(rtnl_msg_handlers[protocol]); + tab = rcu_replace_pointer_rtnl(rtnl_msg_handlers[protocol], NULL); if (!tab) { rtnl_unlock(); return; } - RCU_INIT_POINTER(rtnl_msg_handlers[protocol], NULL); for (msgindex = 0; msgindex < RTM_NR_MSGTYPES; msgindex++) { - link = rtnl_dereference(tab[msgindex]); - if (!link) - continue; - - RCU_INIT_POINTER(tab[msgindex], NULL); + link = rcu_replace_pointer_rtnl(tab[msgindex], NULL); kfree_rcu(link, rcu); } rtnl_unlock(); |