Commit 5380d64f authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

rtnetlink: move rtnl_lock handling out of af_netlink 



Now that we have an intermediate layer of code for handling
rtnl-level netlink dump quirks, we can move the rtnl_lock
taking there.

For dump handlers with RTNL_FLAG_DUMP_SPLIT_NLM_DONE we can
avoid taking rtnl_lock just to generate NLM_DONE, once again.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c917b26e

net/core/rtnetlink.c

+7 −2
Original line number Diff line number Diff line
@@ -6486,6 +6486,7 @@ static int rtnl_mdb_del(struct sk_buff *skb, struct nlmsghdr *nlh, 


static int rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)

{

	const bool needs_lock = !(cb->flags & RTNL_FLAG_DUMP_UNLOCKED);

	rtnl_dumpit_func dumpit = cb->data;

	int err;
@@ -6495,7 +6496,11 @@ static int rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 
	if (!dumpit)

		return 0;



	if (needs_lock)

		rtnl_lock();

	err = dumpit(skb, cb);

	if (needs_lock)

		rtnl_unlock();



	/* Old dump handlers used to send NLM_DONE as in a separate recvmsg().

	 * Some applications which parse netlink manually depend on this.
@@ -6515,7 +6520,8 @@ static int rtnetlink_dump_start(struct sock *ssk, struct sk_buff *skb, 
				const struct nlmsghdr *nlh,

				struct netlink_dump_control *control)

{

	if (control->flags & RTNL_FLAG_DUMP_SPLIT_NLM_DONE) {

	if (control->flags & RTNL_FLAG_DUMP_SPLIT_NLM_DONE ||

	    !(control->flags & RTNL_FLAG_DUMP_UNLOCKED)) {

		WARN_ON(control->data);

		control->data = control->dump;

		control->dump = rtnl_dumpit;
@@ -6703,7 +6709,6 @@ static int __net_init rtnetlink_net_init(struct net *net) 
	struct netlink_kernel_cfg cfg = {

		.groups		= RTNLGRP_MAX,

		.input		= rtnetlink_rcv,

		.cb_mutex	= &rtnl_mutex,

		.flags		= NL_CFG_F_NONROOT_RECV,

		.bind		= rtnetlink_bind,

	};

net/netlink/af_netlink.c

+0 −2
Original line number Diff line number Diff line
@@ -2330,8 +2330,6 @@ static int netlink_dump(struct sock *sk, bool lock_taken) 


		cb->extack = &extack;



		if (cb->flags & RTNL_FLAG_DUMP_UNLOCKED)

			extra_mutex = NULL;

		if (extra_mutex)

			mutex_lock(extra_mutex);

		nlk->dump_done_errno = cb->dump(skb, cb);