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Commit 4e407ff5 authored by Cong Wang's avatar Cong Wang Committed by David S. Miller
Browse files

act_ife: move tcfa_lock down to where necessary 



The only time we need to take tcfa_lock is when adding
a new metainfo to an existing ife->metalist. We don't need
to take tcfa_lock so early and so broadly in tcf_ife_init().

This means we can always take ife_mod_lock first, avoid the
reverse locking ordering warning as reported by Vlad.

Reported-by: default avatarVlad Buslov <vladbu@mellanox.com>
Tested-by: default avatarVlad Buslov <vladbu@mellanox.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8ce5be1c

net/sched/act_ife.c

+13 −25
Original line number Diff line number Diff line
@@ -265,11 +265,8 @@ static const char *ife_meta_id2name(u32 metaid) 
#endif



/* called when adding new meta information

 * under ife->tcf_lock for existing action

*/

static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,

				void *val, int len, bool exists,

				bool rtnl_held)

static int load_metaops_and_vet(u32 metaid, void *val, int len, bool rtnl_held)

{

	struct tcf_meta_ops *ops = find_ife_oplist(metaid);

	int ret = 0;
@@ -277,15 +274,11 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid, 
	if (!ops) {

		ret = -ENOENT;

#ifdef CONFIG_MODULES

		if (exists)

			spin_unlock_bh(&ife->tcf_lock);

		if (rtnl_held)

			rtnl_unlock();

		request_module("ife-meta-%s", ife_meta_id2name(metaid));

		if (rtnl_held)

			rtnl_lock();

		if (exists)

			spin_lock_bh(&ife->tcf_lock);

		ops = find_ife_oplist(metaid);

#endif

	}
@@ -302,10 +295,9 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid, 
}



/* called when adding new meta information

 * under ife->tcf_lock for existing action

*/

static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,

			int len, bool atomic)

			int len, bool atomic, bool exists)

{

	struct tcf_meta_info *mi = NULL;

	struct tcf_meta_ops *ops = find_ife_oplist(metaid);
@@ -332,12 +324,16 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, 
		}

	}



	if (exists)

		spin_lock_bh(&ife->tcf_lock);

	list_add_tail(&mi->metalist, &ife->metalist);

	if (exists)

		spin_unlock_bh(&ife->tcf_lock);



	return ret;

}



static int use_all_metadata(struct tcf_ife_info *ife)

static int use_all_metadata(struct tcf_ife_info *ife, bool exists)

{

	struct tcf_meta_ops *o;

	int rc = 0;
@@ -345,7 +341,7 @@ static int use_all_metadata(struct tcf_ife_info *ife) 


	read_lock(&ife_mod_lock);

	list_for_each_entry(o, &ifeoplist, list) {

		rc = add_metainfo(ife, o->metaid, NULL, 0, true);

		rc = add_metainfo(ife, o->metaid, NULL, 0, true, exists);

		if (rc == 0)

			installed += 1;

	}
@@ -422,7 +418,6 @@ static void tcf_ife_cleanup(struct tc_action *a) 
		kfree_rcu(p, rcu);

}



/* under ife->tcf_lock for existing action */

static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,

			     bool exists, bool rtnl_held)

{
@@ -436,12 +431,11 @@ static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb, 
			val = nla_data(tb[i]);

			len = nla_len(tb[i]);



			rc = load_metaops_and_vet(ife, i, val, len, exists,

						  rtnl_held);

			rc = load_metaops_and_vet(i, val, len, rtnl_held);

			if (rc != 0)

				return rc;



			rc = add_metainfo(ife, i, val, len, exists);

			rc = add_metainfo(ife, i, val, len, false, exists);

			if (rc)

				return rc;

		}
@@ -540,8 +534,6 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, 
		p->eth_type = ife_type;

	}



	if (exists)

		spin_lock_bh(&ife->tcf_lock);



	if (ret == ACT_P_CREATED)

		INIT_LIST_HEAD(&ife->metalist);
@@ -551,10 +543,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, 
				       NULL, NULL);

		if (err) {

metadata_parse_err:

			if (exists)

				spin_unlock_bh(&ife->tcf_lock);

			tcf_idr_release(*a, bind);



			kfree(p);

			return err;

		}
@@ -569,17 +558,16 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, 
		 * as we can. You better have at least one else we are

		 * going to bail out

		 */

		err = use_all_metadata(ife);

		err = use_all_metadata(ife, exists);

		if (err) {

			if (exists)

				spin_unlock_bh(&ife->tcf_lock);

			tcf_idr_release(*a, bind);



			kfree(p);

			return err;

		}

	}



	if (exists)

		spin_lock_bh(&ife->tcf_lock);

	ife->tcf_action = parm->action;

	/* protected by tcf_lock when modifying existing action */

	rcu_swap_protected(ife->params, p, 1);