Commit 7a472814 authored by Vlad Buslov's avatar Vlad Buslov Committed by David S. Miller
Browse files

net: sched: lock action when translating it to flow_action infra 



In order to remove dependency on rtnl lock, take action's tcfa_lock when
constructing its representation as flow_action_entry structure.

Refactor tcf_sample_get_group() to assume that caller holds tcf_lock and
don't take it manually. This callback is only called from flow_action infra
representation translator which now calls it with tcf_lock held, so this
refactoring is necessary to prevent deadlock.

Allocate memory with GFP_ATOMIC flag for ip_tunnel_info copy because
tcf_tunnel_info_copy() is only called from flow_action representation infra
code with tcf_lock spinlock taken.

Signed-off-by: default avatarVlad Buslov <vladbu@mellanox.com>
Acked-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 92df9f8a

include/net/tc_act/tc_tunnel_key.h

+1 −1
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ tcf_tunnel_info_copy(const struct tc_action *a) 
	if (tun) {

		size_t tun_size = sizeof(*tun) + tun->options_len;

		struct ip_tunnel_info *tun_copy = kmemdup(tun, tun_size,

							  GFP_KERNEL);

							  GFP_ATOMIC);



		return tun_copy;

	}

net/sched/act_sample.c

+0 −2
Original line number Diff line number Diff line
@@ -267,14 +267,12 @@ tcf_sample_get_group(const struct tc_action *a, 
	struct tcf_sample *s = to_sample(a);

	struct psample_group *group;



	spin_lock_bh(&s->tcf_lock);

	group = rcu_dereference_protected(s->psample_group,

					  lockdep_is_held(&s->tcf_lock));

	if (group) {

		psample_group_take(group);

		*destructor = tcf_psample_group_put;

	}

	spin_unlock_bh(&s->tcf_lock);



	return group;

}

net/sched/cls_api.c

+11 −6
Original line number Diff line number Diff line
@@ -3435,7 +3435,7 @@ static void tcf_sample_get_group(struct flow_action_entry *entry, 
int tc_setup_flow_action(struct flow_action *flow_action,

			 const struct tcf_exts *exts, bool rtnl_held)

{

	const struct tc_action *act;

	struct tc_action *act;

	int i, j, k, err = 0;



	if (!exts)
@@ -3449,6 +3449,7 @@ int tc_setup_flow_action(struct flow_action *flow_action, 
		struct flow_action_entry *entry;



		entry = &flow_action->entries[j];

		spin_lock_bh(&act->tcfa_lock);

		if (is_tcf_gact_ok(act)) {

			entry->id = FLOW_ACTION_ACCEPT;

		} else if (is_tcf_gact_shot(act)) {
@@ -3489,13 +3490,13 @@ int tc_setup_flow_action(struct flow_action *flow_action, 
				break;

			default:

				err = -EOPNOTSUPP;

				goto err_out;

				goto err_out_locked;

			}

		} else if (is_tcf_tunnel_set(act)) {

			entry->id = FLOW_ACTION_TUNNEL_ENCAP;

			err = tcf_tunnel_encap_get_tunnel(entry, act);

			if (err)

				goto err_out;

				goto err_out_locked;

		} else if (is_tcf_tunnel_release(act)) {

			entry->id = FLOW_ACTION_TUNNEL_DECAP;

		} else if (is_tcf_pedit(act)) {
@@ -3509,7 +3510,7 @@ int tc_setup_flow_action(struct flow_action *flow_action, 
					break;

				default:

					err = -EOPNOTSUPP;

					goto err_out;

					goto err_out_locked;

				}

				entry->mangle.htype = tcf_pedit_htype(act, k);

				entry->mangle.mask = tcf_pedit_mask(act, k);
@@ -3560,15 +3561,16 @@ int tc_setup_flow_action(struct flow_action *flow_action, 
				entry->mpls_mangle.ttl = tcf_mpls_ttl(act);

				break;

			default:

				goto err_out;

				goto err_out_locked;

			}

		} else if (is_tcf_skbedit_ptype(act)) {

			entry->id = FLOW_ACTION_PTYPE;

			entry->ptype = tcf_skbedit_ptype(act);

		} else {

			err = -EOPNOTSUPP;

			goto err_out;

			goto err_out_locked;

		}

		spin_unlock_bh(&act->tcfa_lock);



		if (!is_tcf_pedit(act))

			j++;
@@ -3582,6 +3584,9 @@ err_out: 
		tc_cleanup_flow_action(flow_action);



	return err;

err_out_locked:

	spin_unlock_bh(&act->tcfa_lock);

	goto err_out;

}

EXPORT_SYMBOL(tc_setup_flow_action);

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