Commit 0fca55ed authored by Vlad Buslov's avatar Vlad Buslov Committed by Jakub Kicinski
Browse files

net: sched: remove redundant 'rtnl_held' argument 



Functions tfilter_notify_chain() and tcf_get_next_proto() are always called
with rtnl lock held in current implementation. Moreover, attempting to call
them without rtnl lock would cause a warning down the call chain in
function __tcf_get_next_proto() that requires the lock to be held by
callers. Remove the 'rtnl_held' argument in order to simplify the code and
make rtnl lock requirement explicit.

Signed-off-by: default avatarVlad Buslov <vladbu@nvidia.com>
Link: https://lore.kernel.org/r/20201127151205.23492-1-vladbu@nvidia.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent cb7fb043

include/net/pkt_cls.h

+1 −1
Original line number Diff line number Diff line
@@ -48,7 +48,7 @@ void tcf_chain_put_by_act(struct tcf_chain *chain); 
struct tcf_chain *tcf_get_next_chain(struct tcf_block *block,

				     struct tcf_chain *chain);

struct tcf_proto *tcf_get_next_proto(struct tcf_chain *chain,

				     struct tcf_proto *tp, bool rtnl_held);

				     struct tcf_proto *tp);

void tcf_block_netif_keep_dst(struct tcf_block *block);

int tcf_block_get(struct tcf_block **p_block,

		  struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q,

net/sched/cls_api.c

+8 −10
Original line number Diff line number Diff line
@@ -991,13 +991,12 @@ __tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp) 
 */



struct tcf_proto *

tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp,

		   bool rtnl_held)

tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp)

{

	struct tcf_proto *tp_next = __tcf_get_next_proto(chain, tp);



	if (tp)

		tcf_proto_put(tp, rtnl_held, NULL);

		tcf_proto_put(tp, true, NULL);



	return tp_next;

}
@@ -1924,15 +1923,14 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb, 
static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,

				 struct tcf_block *block, struct Qdisc *q,

				 u32 parent, struct nlmsghdr *n,

				 struct tcf_chain *chain, int event,

				 bool rtnl_held)

				 struct tcf_chain *chain, int event)

{

	struct tcf_proto *tp;



	for (tp = tcf_get_next_proto(chain, NULL, rtnl_held);

	     tp; tp = tcf_get_next_proto(chain, tp, rtnl_held))

	for (tp = tcf_get_next_proto(chain, NULL);

	     tp; tp = tcf_get_next_proto(chain, tp))

		tfilter_notify(net, oskb, n, tp, block,

			       q, parent, NULL, event, false, rtnl_held);

			       q, parent, NULL, event, false, true);

}



static void tfilter_put(struct tcf_proto *tp, void *fh)
@@ -2262,7 +2260,7 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, 


	if (prio == 0) {

		tfilter_notify_chain(net, skb, block, q, parent, n,

				     chain, RTM_DELTFILTER, rtnl_held);

				     chain, RTM_DELTFILTER);

		tcf_chain_flush(chain, rtnl_held);

		err = 0;

		goto errout;
@@ -2895,7 +2893,7 @@ replay: 
		break;

	case RTM_DELCHAIN:

		tfilter_notify_chain(net, skb, block, q, parent, n,

				     chain, RTM_DELTFILTER, true);

				     chain, RTM_DELTFILTER);

		/* Flush the chain first as the user requested chain removal. */

		tcf_chain_flush(chain, true);

		/* In case the chain was successfully deleted, put a reference

net/sched/sch_api.c

+2 −2
Original line number Diff line number Diff line
@@ -1943,8 +1943,8 @@ static int tc_bind_class_walker(struct Qdisc *q, unsigned long cl, 
	     chain = tcf_get_next_chain(block, chain)) {

		struct tcf_proto *tp;



		for (tp = tcf_get_next_proto(chain, NULL, true);

		     tp; tp = tcf_get_next_proto(chain, tp, true)) {

		for (tp = tcf_get_next_proto(chain, NULL);

		     tp; tp = tcf_get_next_proto(chain, tp)) {

			struct tcf_bind_args arg = {};



			arg.w.fn = tcf_node_bind;

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