nfp: flower: avoid rmmod nfp crash issues

When there are CT table entries, and you rmmod nfp, the following
events can happen:

task1：
    nfp_net_pci_remove
          ↓
    nfp_flower_stop->(asynchronous)tcf_ct_flow_table_cleanup_work(3)
          ↓
    nfp_zone_table_entry_destroy(1)

task2：
    nfp_fl_ct_handle_nft_flow(2)

When the execution order is (1)->(2)->(3), it will crash. Therefore, in
the function nfp_fl_ct_del_flow, nf_flow_table_offload_del_cb needs to
be executed synchronously.

At the same time, in order to solve the deadlock problem and the problem
of rtnl_lock sometimes failing, replace rtnl_lock with the private
nfp_fl_lock.

Fixes: 7cc93d88 ("nfp: flower-ct: remove callback delete deadlock")
Cc: stable@vger.kernel.org
Signed-off-by: Yanguo Li <yanguo.li@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/cmsg.c

@@ -210,6 +210,7 @@ nfp_flower_cmsg_merge_hint_rx(struct nfp_app *app, struct sk_buff *skb)
 	unsigned int msg_len = nfp_flower_cmsg_get_data_len(skb);
 	struct nfp_flower_cmsg_merge_hint *msg;
 	struct nfp_fl_payload *sub_flows[2];
+	struct nfp_flower_priv *priv;
 	int err, i, flow_cnt;
 
 	msg = nfp_flower_cmsg_get_data(skb);
@@ -228,14 +229,15 @@ nfp_flower_cmsg_merge_hint_rx(struct nfp_app *app, struct sk_buff *skb)
 		return;
 	}
 
-	rtnl_lock();
+	priv = app->priv;
+	mutex_lock(&priv->nfp_fl_lock);
 	for (i = 0; i < flow_cnt; i++) {
 		u32 ctx = be32_to_cpu(msg->flow[i].host_ctx);
 
 		sub_flows[i] = nfp_flower_get_fl_payload_from_ctx(app, ctx);
 		if (!sub_flows[i]) {
 			nfp_flower_cmsg_warn(app, "Invalid flow in merge hint\n");
-			goto err_rtnl_unlock;
+			goto err_mutex_unlock;
 		}
 	}
 
@@ -244,8 +246,8 @@ nfp_flower_cmsg_merge_hint_rx(struct nfp_app *app, struct sk_buff *skb)
 	if (err == -ENOMEM)
 		nfp_flower_cmsg_warn(app, "Flow merge memory fail.\n");
 
-err_rtnl_unlock:
-	rtnl_unlock();
+err_mutex_unlock:
+	mutex_unlock(&priv->nfp_fl_lock);
 }
 
 static void

drivers/net/ethernet/netronome/nfp/flower/conntrack.c

@@ -2131,8 +2131,6 @@ nfp_fl_ct_offload_nft_flow(struct nfp_fl_ct_zone_entry *zt, struct flow_cls_offl
 	struct nfp_fl_ct_flow_entry *ct_entry;
 	struct netlink_ext_ack *extack = NULL;
 
-	ASSERT_RTNL();
-
 	extack = flow->common.extack;
 	switch (flow->command) {
 	case FLOW_CLS_REPLACE:
@@ -2178,9 +2176,13 @@ int nfp_fl_ct_handle_nft_flow(enum tc_setup_type type, void *type_data, void *cb
 
 	switch (type) {
 	case TC_SETUP_CLSFLOWER:
-		rtnl_lock();
+		while (!mutex_trylock(&zt->priv->nfp_fl_lock)) {
+			if (!zt->nft) /* avoid deadlock */
+				return err;
+			msleep(20);
+		}
 		err = nfp_fl_ct_offload_nft_flow(zt, flow);
-		rtnl_unlock();
+		mutex_unlock(&zt->priv->nfp_fl_lock);
 		break;
 	default:
 		return -EOPNOTSUPP;
@@ -2208,6 +2210,7 @@ int nfp_fl_ct_del_flow(struct nfp_fl_ct_map_entry *ct_map_ent)
 	struct nfp_fl_ct_flow_entry *ct_entry;
 	struct nfp_fl_ct_zone_entry *zt;
 	struct rhashtable *m_table;
+	struct nf_flowtable *nft;
 
 	if (!ct_map_ent)
 		return -ENOENT;
@@ -2226,8 +2229,12 @@ int nfp_fl_ct_del_flow(struct nfp_fl_ct_map_entry *ct_map_ent)
 		if (ct_map_ent->cookie > 0)
 			kfree(ct_map_ent);
 
-		if (!zt->pre_ct_count) {
-			zt->nft = NULL;
+		if (!zt->pre_ct_count && zt->nft) {
+			nft = zt->nft;
+			zt->nft = NULL; /* avoid deadlock */
+			nf_flow_table_offload_del_cb(nft,
+						     nfp_fl_ct_handle_nft_flow,
+						     zt);
 			nfp_fl_ct_clean_nft_entries(zt);
 		}
 		break;

drivers/net/ethernet/netronome/nfp/flower/main.h

@@ -297,6 +297,7 @@ struct nfp_fl_internal_ports {
  * @predt_list:		List to keep track of decap pretun flows
  * @neigh_table:	Table to keep track of neighbor entries
  * @predt_lock:		Lock to serialise predt/neigh table updates
+ * @nfp_fl_lock:	Lock to protect the flow offload operation
  */
 struct nfp_flower_priv {
 	struct nfp_app *app;
@@ -339,6 +340,7 @@ struct nfp_flower_priv {
 	struct list_head predt_list;
 	struct rhashtable neigh_table;
 	spinlock_t predt_lock; /* Lock to serialise predt/neigh table updates */
+	struct mutex nfp_fl_lock; /* Protect the flow operation */
 };
 
 /**

drivers/net/ethernet/netronome/nfp/flower/metadata.c

@@ -528,6 +528,8 @@ int nfp_flower_metadata_init(struct nfp_app *app, u64 host_ctx_count,
 	if (err)
 		goto err_free_stats_ctx_table;
 
+	mutex_init(&priv->nfp_fl_lock);
+
 	err = rhashtable_init(&priv->ct_zone_table, &nfp_zone_table_params);
 	if (err)
 		goto err_free_merge_table;

drivers/net/ethernet/netronome/nfp/flower/offload.c

@@ -1009,8 +1009,6 @@ int nfp_flower_merge_offloaded_flows(struct nfp_app *app,
 	u64 parent_ctx = 0;
 	int err;
 
-	ASSERT_RTNL();
-
 	if (sub_flow1 == sub_flow2 ||
 	    nfp_flower_is_merge_flow(sub_flow1) ||
 	    nfp_flower_is_merge_flow(sub_flow2))
@@ -1727,19 +1725,30 @@ static int
 nfp_flower_repr_offload(struct nfp_app *app, struct net_device *netdev,
 			struct flow_cls_offload *flower)
 {
+	struct nfp_flower_priv *priv = app->priv;
+	int ret;
+
 	if (!eth_proto_is_802_3(flower->common.protocol))
 		return -EOPNOTSUPP;
 
+	mutex_lock(&priv->nfp_fl_lock);
 	switch (flower->command) {
 	case FLOW_CLS_REPLACE:
-		return nfp_flower_add_offload(app, netdev, flower);
+		ret = nfp_flower_add_offload(app, netdev, flower);
+		break;
 	case FLOW_CLS_DESTROY:
-		return nfp_flower_del_offload(app, netdev, flower);
+		ret = nfp_flower_del_offload(app, netdev, flower);
+		break;
 	case FLOW_CLS_STATS:
-		return nfp_flower_get_stats(app, netdev, flower);
+		ret = nfp_flower_get_stats(app, netdev, flower);
+		break;
 	default:
-		return -EOPNOTSUPP;
+		ret = -EOPNOTSUPP;
+		break;
 	}
+	mutex_unlock(&priv->nfp_fl_lock);
+
+	return ret;
 }
 
 static int nfp_flower_setup_tc_block_cb(enum tc_setup_type type,
@@ -1778,6 +1787,7 @@ static int nfp_flower_setup_tc_block(struct net_device *netdev,
 	repr_priv = repr->app_priv;
 	repr_priv->block_shared = f->block_shared;
 	f->driver_block_list = &nfp_block_cb_list;
+	f->unlocked_driver_cb = true;
 
 	switch (f->command) {
 	case FLOW_BLOCK_BIND:
@@ -1876,6 +1886,8 @@ nfp_flower_setup_indr_tc_block(struct net_device *netdev, struct Qdisc *sch, str
 	     nfp_flower_internal_port_can_offload(app, netdev)))
 		return -EOPNOTSUPP;
 
+	f->unlocked_driver_cb = true;
+
 	switch (f->command) {
 	case FLOW_BLOCK_BIND:
 		cb_priv = nfp_flower_indr_block_cb_priv_lookup(app, netdev);

drivers/net/ethernet/netronome/nfp/flower/qos_conf.c

@@ -523,25 +523,31 @@ int nfp_flower_setup_qos_offload(struct nfp_app *app, struct net_device *netdev,
 {
 	struct netlink_ext_ack *extack = flow->common.extack;
 	struct nfp_flower_priv *fl_priv = app->priv;
+	int ret;
 
 	if (!(fl_priv->flower_ext_feats & NFP_FL_FEATS_VF_RLIM)) {
 		NL_SET_ERR_MSG_MOD(extack, "unsupported offload: loaded firmware does not support qos rate limit offload");
 		return -EOPNOTSUPP;
 	}
 
+	mutex_lock(&fl_priv->nfp_fl_lock);
 	switch (flow->command) {
 	case TC_CLSMATCHALL_REPLACE:
-		return nfp_flower_install_rate_limiter(app, netdev, flow,
-						       extack);
+		ret = nfp_flower_install_rate_limiter(app, netdev, flow, extack);
+		break;
 	case TC_CLSMATCHALL_DESTROY:
-		return nfp_flower_remove_rate_limiter(app, netdev, flow,
-						      extack);
+		ret = nfp_flower_remove_rate_limiter(app, netdev, flow, extack);
+		break;
 	case TC_CLSMATCHALL_STATS:
-		return nfp_flower_stats_rate_limiter(app, netdev, flow,
-						     extack);
+		ret = nfp_flower_stats_rate_limiter(app, netdev, flow, extack);
+		break;
 	default:
-		return -EOPNOTSUPP;
+		ret = -EOPNOTSUPP;
+		break;
 	}
+	mutex_unlock(&fl_priv->nfp_fl_lock);
+
+	return ret;
 }
 
 /* Offload tc action, currently only for tc police */