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Commit 62256f98 authored by Florian Westphal's avatar Florian Westphal Committed by David S. Miller
Browse files

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: default avatarFlorian Westphal <fw@strlen.de>
Reviewed-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6853dd48

include/net/rtnetlink.h

+4 −0
Original line number Diff line number Diff line
@@ -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,

net/core/rtnetlink.c

+15 −0
Original line number Diff line number Diff line
@@ -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();