sfc: ARFS filter IDs

Associate an arbitrary ID with each ARFS filter, allowing to properly query
 for expiry.  The association is maintained in a hash table, which is
 protected by a spinlock.

v3: fix build warnings when CONFIG_RFS_ACCEL is disabled (thanks lkp-robot).
v2: fixed uninitialised variable (thanks davem and lkp-robot).

Fixes: 3af0f34290f6 ("sfc: replace asynchronous filter operations")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 57 insertions, 5 deletions

diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index 9c593c661cbf..64a94f242027 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -834,9 +834,29 @@ static void efx_filter_rfs_work(struct work_struct *data)
 	struct efx_nic *efx = netdev_priv(req->net_dev);
 	struct efx_channel *channel = efx_get_channel(efx, req->rxq_index);
 	int slot_idx = req - efx->rps_slot;
+	struct efx_arfs_rule *rule;
+	u16 arfs_id = 0;
 	int rc;
 
 	rc = efx->type->filter_insert(efx, &req->spec, true);
+	if (efx->rps_hash_table) {
+		spin_lock_bh(&efx->rps_hash_lock);
+		rule = efx_rps_hash_find(efx, &req->spec);
+		/* The rule might have already gone, if someone else's request
+		 * for the same spec was already worked and then expired before
+		 * we got around to our work.  In that case we have nothing
+		 * tying us to an arfs_id, meaning that as soon as the filter
+		 * is considered for expiry it will be removed.
+		 */
+		if (rule) {
+			if (rc < 0)
+				rule->filter_id = EFX_ARFS_FILTER_ID_ERROR;
+			else
+				rule->filter_id = rc;
+			arfs_id = rule->arfs_id;
+		}
+		spin_unlock_bh(&efx->rps_hash_lock);
+	}
 	if (rc >= 0) {
 		/* Remember this so we can check whether to expire the filter
 		 * later.
@@ -848,18 +868,18 @@ static void efx_filter_rfs_work(struct work_struct *data)
 
 		if (req->spec.ether_type == htons(ETH_P_IP))
 			netif_info(efx, rx_status, efx->net_dev,
-				   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d]\n",
+				   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d id %u]\n",
 				   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
 				   req->spec.rem_host, ntohs(req->spec.rem_port),
 				   req->spec.loc_host, ntohs(req->spec.loc_port),
-				   req->rxq_index, req->flow_id, rc);
+				   req->rxq_index, req->flow_id, rc, arfs_id);
 		else
 			netif_info(efx, rx_status, efx->net_dev,
-				   "steering %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u filter %d]\n",
+				   "steering %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u filter %d id %u]\n",
 				   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
 				   req->spec.rem_host, ntohs(req->spec.rem_port),
 				   req->spec.loc_host, ntohs(req->spec.loc_port),
-				   req->rxq_index, req->flow_id, rc);
+				   req->rxq_index, req->flow_id, rc, arfs_id);
 	}
 
 	/* Release references */
@@ -872,8 +892,10 @@ int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 	struct efx_async_filter_insertion *req;
+	struct efx_arfs_rule *rule;
 	struct flow_keys fk;
 	int slot_idx;
+	bool new;
 	int rc;
 
 	/* find a free slot */
@@ -926,12 +948,42 @@ int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 	req->spec.rem_port = fk.ports.src;
 	req->spec.loc_port = fk.ports.dst;
 
+	if (efx->rps_hash_table) {
+		/* Add it to ARFS hash table */
+		spin_lock(&efx->rps_hash_lock);
+		rule = efx_rps_hash_add(efx, &req->spec, &new);
+		if (!rule) {
+			rc = -ENOMEM;
+			goto out_unlock;
+		}
+		if (new)
+			rule->arfs_id = efx->rps_next_id++ % RPS_NO_FILTER;
+		rc = rule->arfs_id;
+		/* Skip if existing or pending filter already does the right thing */
+		if (!new && rule->rxq_index == rxq_index &&
+		    rule->filter_id >= EFX_ARFS_FILTER_ID_PENDING)
+			goto out_unlock;
+		rule->rxq_index = rxq_index;
+		rule->filter_id = EFX_ARFS_FILTER_ID_PENDING;
+		spin_unlock(&efx->rps_hash_lock);
+	} else {
+		/* Without an ARFS hash table, we just use arfs_id 0 for all
+		 * filters.  This means if multiple flows hash to the same
+		 * flow_id, all but the most recently touched will be eligible
+		 * for expiry.
+		 */
+		rc = 0;
+	}
+
+	/* Queue the request */
 	dev_hold(req->net_dev = net_dev);
 	INIT_WORK(&req->work, efx_filter_rfs_work);
 	req->rxq_index = rxq_index;
 	req->flow_id = flow_id;
 	schedule_work(&req->work);
-	return 0;
+	return rc;
+out_unlock:
+	spin_unlock(&efx->rps_hash_lock);
 out_clear:
 	clear_bit(slot_idx, &efx->rps_slot_map);
 	return rc;