ice: Add initial support framework for LAG

Add the framework and initial implementation for receiving and processing
netdev bonding events.  This is only the software support and the
implementation of the HW offload for bonding support will be coming at a
later time.  There are some architectural gaps that need to be closed
before that happens.

Because this is a software only solution that supports in kernel bonding,
SR-IOV is not supported with this implementation.

Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_lag.h b/drivers/net/ethernet/intel/ice/ice_lag.h
new file mode 100644
index 000000000000..c2e3688dd8fd
--- /dev/null
+++ b/drivers/net/ethernet/intel/ice/ice_lag.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2018-2021, Intel Corporation. */
+
+#ifndef _ICE_LAG_H_
+#define _ICE_LAG_H_
+
+#include <linux/netdevice.h>
+
+/* LAG roles for netdev */
+enum ice_lag_role {
+	ICE_LAG_NONE,
+	ICE_LAG_PRIMARY,
+	ICE_LAG_BACKUP,
+	ICE_LAG_UNSET
+};
+
+struct ice_pf;
+
+/* LAG info struct */
+struct ice_lag {
+	struct ice_pf *pf; /* backlink to PF struct */
+	struct net_device *netdev; /* this PF's netdev */
+	struct net_device *peer_netdev;
+	struct net_device *upper_netdev; /* upper bonding netdev */
+	struct notifier_block notif_block;
+	u8 bonded:1; /* currently bonded */
+	u8 master:1; /* this is a master */
+	u8 handler:1; /* did we register a rx_netdev_handler */
+	/* each thing blocking bonding will increment this value by one.
+	 * If this value is zero, then bonding is allowed.
+	 */
+	u16 dis_lag;
+	u8 role;
+};
+
+int ice_init_lag(struct ice_pf *pf);
+void ice_deinit_lag(struct ice_pf *pf);
+rx_handler_result_t ice_lag_nop_handler(struct sk_buff **pskb);
+
+/**
+ * ice_disable_lag - increment LAG disable count
+ * @lag: LAG struct
+ */
+static inline void ice_disable_lag(struct ice_lag *lag)
+{
+	/* If LAG this PF is not already disabled, disable it */
+	rtnl_lock();
+	if (!netdev_is_rx_handler_busy(lag->netdev)) {
+		if (!netdev_rx_handler_register(lag->netdev,
+						ice_lag_nop_handler,
+						NULL))
+			lag->handler = true;
+	}
+	rtnl_unlock();
+	lag->dis_lag++;
+}
+
+/**
+ * ice_enable_lag - decrement disable count for a PF
+ * @lag: LAG struct
+ *
+ * Decrement the disable counter for a port, and if that count reaches
+ * zero, then remove the no-op Rx handler from that netdev
+ */
+static inline void ice_enable_lag(struct ice_lag *lag)
+{
+	if (lag->dis_lag)
+		lag->dis_lag--;
+	if (!lag->dis_lag && lag->handler) {
+		rtnl_lock();
+		netdev_rx_handler_unregister(lag->netdev);
+		rtnl_unlock();
+		lag->handler = false;
+	}
+}
+
+/**
+ * ice_is_lag_dis - is LAG disabled
+ * @lag: LAG struct
+ *
+ * Return true if bonding is disabled
+ */
+static inline bool ice_is_lag_dis(struct ice_lag *lag)
+{
+	return !!(lag->dis_lag);
+}
+#endif /* _ICE_LAG_H_ */