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rtnetlink: add RTNL_FLAG_DOIT_UNLOCKED

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Allow callers to tell rtnetlink core that its doit callback
should be invoked without holding rtnl mutex.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal 2017-08-09 20:41:52 +02:00 committed by David S. Miller
parent 6853dd4881
commit 62256f98f2
2 changed files with 19 additions and 0 deletions
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4
include/net/rtnetlink.h
View File

@ -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,

15
net/core/rtnetlink.c
View File

@ -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();