From 62256f98f244fbb1c7a10465e1ee412f209d8978 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 9 Aug 2017 20:41:52 +0200 Subject: [PATCH] rtnetlink: add RTNL_FLAG_DOIT_UNLOCKED Allow callers to tell rtnetlink core that its doit callback should be invoked without holding rtnl mutex. Signed-off-by: Florian Westphal Reviewed-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- include/net/rtnetlink.h | 4 ++++ net/core/rtnetlink.c | 15 +++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index ac32460a0adb..21837ca68ecc 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -8,6 +8,10 @@ typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *, struct netlink_ext_ack *); typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *); +enum rtnl_link_flags { + RTNL_FLAG_DOIT_UNLOCKED = 1, +}; + int __rtnl_register(int protocol, int msgtype, rtnl_doit_func, rtnl_dumpit_func, unsigned int flags); void rtnl_register(int protocol, int msgtype, diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index d45946177bc8..dd4e50dfa248 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -62,6 +62,7 @@ struct rtnl_link { rtnl_doit_func doit; rtnl_dumpit_func dumpit; + unsigned int flags; }; static DEFINE_MUTEX(rtnl_mutex); @@ -184,6 +185,7 @@ int __rtnl_register(int protocol, int msgtype, tab[msgindex].doit = doit; if (dumpit) tab[msgindex].dumpit = dumpit; + tab[msgindex].flags |= flags; return 0; } @@ -233,6 +235,7 @@ int rtnl_unregister(int protocol, int msgtype) handlers[msgindex].doit = NULL; handlers[msgindex].dumpit = NULL; + handlers[msgindex].flags = 0; rtnl_unlock(); return 0; @@ -4143,6 +4146,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, struct rtnl_link *handlers; int err = -EOPNOTSUPP; rtnl_doit_func doit; + unsigned int flags; int kind; int family; int type; @@ -4209,6 +4213,17 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, return err; } + flags = READ_ONCE(handlers[type].flags); + if (flags & RTNL_FLAG_DOIT_UNLOCKED) { + refcount_inc(&rtnl_msg_handlers_ref[family]); + doit = READ_ONCE(handlers[type].doit); + rcu_read_unlock(); + if (doit) + err = doit(skb, nlh, extack); + refcount_dec(&rtnl_msg_handlers_ref[family]); + return err; + } + rcu_read_unlock(); rtnl_lock(); -- 2.20.1