ionic: handle mac filter overflow

Make sure we go into PROMISC mode when we have too many
filters by specifically counting the filters that successfully
get saved to the firmware.

The device advertises max_ucast_filters and max_mcast_filters,
but really only has max_ucast_filters slots available for
uc and mc filters combined.
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/pensando/ionic/ionic_lif.c

@@ -1256,6 +1256,8 @@ int ionic_lif_addr_add(struct ionic_lif *lif, const u8 *addr)
 			.match = cpu_to_le16(IONIC_RX_FILTER_MATCH_MAC),
 		},
 	};
+	int nfilters = le32_to_cpu(lif->identity->eth.max_ucast_filters);
+	bool mc = is_multicast_ether_addr(addr);
 	struct ionic_rx_filter *f;
 	int err = 0;
 
@@ -1282,7 +1284,13 @@ int ionic_lif_addr_add(struct ionic_lif *lif, const u8 *addr)
 
 	netdev_dbg(lif->netdev, "rx_filter add ADDR %pM\n", addr);
 
-	err = ionic_adminq_post_wait(lif, &ctx);
+	/* Don't bother with the write to FW if we know there's no room,
+	 * we can try again on the next sync attempt.
+	 */
+	if ((lif->nucast + lif->nmcast) >= nfilters)
+		err = -ENOSPC;
+	else
+		err = ionic_adminq_post_wait(lif, &ctx);
 
 	spin_lock_bh(&lif->rx_filters.lock);
 	if (err && err != -EEXIST) {
@@ -1292,9 +1300,18 @@ int ionic_lif_addr_add(struct ionic_lif *lif, const u8 *addr)
 			f->state = IONIC_FILTER_STATE_NEW;
 
 		spin_unlock_bh(&lif->rx_filters.lock);
-		return err;
+
+		if (err == -ENOSPC)
+			return 0;
+		else
+			return err;
 	}
 
+	if (mc)
+		lif->nmcast++;
+	else
+		lif->nucast++;
+
 	f = ionic_rx_filter_by_addr(lif, addr);
 	if (f && f->state == IONIC_FILTER_STATE_OLD) {
 		/* Someone requested a delete while we were adding
@@ -1340,6 +1357,12 @@ int ionic_lif_addr_del(struct ionic_lif *lif, const u8 *addr)
 	state = f->state;
 	ctx.cmd.rx_filter_del.filter_id = cpu_to_le32(f->filter_id);
 	ionic_rx_filter_free(lif, f);
+
+	if (is_multicast_ether_addr(addr) && lif->nmcast)
+		lif->nmcast--;
+	else if (!is_multicast_ether_addr(addr) && lif->nucast)
+		lif->nucast--;
+
 	spin_unlock_bh(&lif->rx_filters.lock);
 
 	if (state != IONIC_FILTER_STATE_NEW) {
@@ -1392,21 +1415,16 @@ void ionic_lif_rx_mode(struct ionic_lif *lif)
 	 *       to see if we can disable NIC PROMISC
 	 */
 	nfilters = le32_to_cpu(lif->identity->eth.max_ucast_filters);
-	if (netdev_uc_count(netdev) + 1 > nfilters) {
+	if ((lif->nucast + lif->nmcast) >= nfilters) {
 		rx_mode |= IONIC_RX_MODE_F_PROMISC;
+		rx_mode |= IONIC_RX_MODE_F_ALLMULTI;
 		lif->uc_overflow = true;
+		lif->mc_overflow = true;
 	} else if (lif->uc_overflow) {
 		lif->uc_overflow = false;
+		lif->mc_overflow = false;
 		if (!(nd_flags & IFF_PROMISC))
 			rx_mode &= ~IONIC_RX_MODE_F_PROMISC;
-	}
-
-	nfilters = le32_to_cpu(lif->identity->eth.max_mcast_filters);
-	if (netdev_mc_count(netdev) > nfilters) {
-		rx_mode |= IONIC_RX_MODE_F_ALLMULTI;
-		lif->mc_overflow = true;
-	} else if (lif->mc_overflow) {
-		lif->mc_overflow = false;
 		if (!(nd_flags & IFF_ALLMULTI))
 			rx_mode &= ~IONIC_RX_MODE_F_ALLMULTI;
 	}