ice: Implement aRFS

Enable accelerated Receive Flow Steering (aRFS). It is used to steer Rx
flows to a specific queue. This functionality is triggered by the network
stack through ndo_rx_flow_steer and requires Flow Director (ntuple on) to
function.

The fltr_info is used to add/remove/update flow rules in the HW, the
fltr_state is used to determine what to do with the filter with respect
to HW and/or SW, and the flow_id is used in co-ordination with the
network stack.

The work for aRFS is split into two paths: the ndo_rx_flow_steer
operation and the ice_service_task. The former is where the kernel hands
us an Rx SKB among other items to setup aRFS and the latter is where
the driver adds/updates/removes filter rules from HW and updates filter
state.

In the Rx path the following things can happen:
        1. New aRFS entries are added to the hash table and the state is
           set to ICE_ARFS_INACTIVE so the filter can be updated in HW
           by the ice_service_task path.
        2. aRFS entries have their Rx Queue updated if we receive a
           pre-existing flow_id and the filter state is ICE_ARFS_ACTIVE.
           The state is set to ICE_ARFS_INACTIVE so the filter can be
           updated in HW by the ice_service_task path.
        3. aRFS entries marked as ICE_ARFS_TODEL are deleted

In the ice_service_task path the following things can happen:
        1. New aRFS entries marked as ICE_ARFS_INACTIVE are added or
           updated in HW.
           and their state is updated to ICE_ARFS_ACTIVE.
        2. aRFS entries are deleted from HW and their state is updated
           to ICE_ARFS_TODEL.

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Madhu Chittim <madhu.chittim@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 82 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_arfs.h b/drivers/net/ethernet/intel/ice/ice_arfs.h
new file mode 100644
index 000000000000..f39cd16403ed
--- /dev/null
+++ b/drivers/net/ethernet/intel/ice/ice_arfs.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2018-2020, Intel Corporation. */
+
+#ifndef _ICE_ARFS_H_
+#define _ICE_ARFS_H_
+enum ice_arfs_fltr_state {
+	ICE_ARFS_INACTIVE,
+	ICE_ARFS_ACTIVE,
+	ICE_ARFS_TODEL,
+};
+
+struct ice_arfs_entry {
+	struct ice_fdir_fltr fltr_info;
+	struct hlist_node list_entry;
+	u64 time_activated;	/* only valid for UDP flows */
+	u32 flow_id;
+	/* fltr_state = 0 - ICE_ARFS_INACTIVE:
+	 *	filter needs to be updated or programmed in HW.
+	 * fltr_state = 1 - ICE_ARFS_ACTIVE:
+	 *	filter is active and programmed in HW.
+	 * fltr_state = 2 - ICE_ARFS_TODEL:
+	 *	filter has been deleted from HW and needs to be removed from
+	 *	the aRFS hash table.
+	 */
+	u8 fltr_state;
+};
+
+struct ice_arfs_entry_ptr {
+	struct ice_arfs_entry *arfs_entry;
+	struct hlist_node list_entry;
+};
+
+struct ice_arfs_active_fltr_cntrs {
+	atomic_t active_tcpv4_cnt;
+	atomic_t active_tcpv6_cnt;
+	atomic_t active_udpv4_cnt;
+	atomic_t active_udpv6_cnt;
+};
+
+#ifdef CONFIG_RFS_ACCEL
+int
+ice_rx_flow_steer(struct net_device *netdev, const struct sk_buff *skb,
+		  u16 rxq_idx, u32 flow_id);
+void ice_clear_arfs(struct ice_vsi *vsi);
+void ice_free_cpu_rx_rmap(struct ice_vsi *vsi);
+void ice_init_arfs(struct ice_vsi *vsi);
+void ice_sync_arfs_fltrs(struct ice_pf *pf);
+int ice_set_cpu_rx_rmap(struct ice_vsi *vsi);
+void ice_remove_arfs(struct ice_pf *pf);
+void ice_rebuild_arfs(struct ice_pf *pf);
+bool
+ice_is_arfs_using_perfect_flow(struct ice_hw *hw,
+			       enum ice_fltr_ptype flow_type);
+#else
+#define ice_sync_arfs_fltrs(pf) do {} while (0)
+#define ice_init_arfs(vsi) do {} while (0)
+#define ice_clear_arfs(vsi) do {} while (0)
+#define ice_remove_arfs(pf) do {} while (0)
+#define ice_free_cpu_rx_rmap(vsi) do {} while (0)
+#define ice_rebuild_arfs(pf) do {} while (0)
+
+static inline int ice_set_cpu_rx_rmap(struct ice_vsi __always_unused *vsi)
+{
+	return 0;
+}
+
+static inline int
+ice_rx_flow_steer(struct net_device __always_unused *netdev,
+		  const struct sk_buff __always_unused *skb,
+		  u16 __always_unused rxq_idx, u32 __always_unused flow_id)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline bool
+ice_is_arfs_using_perfect_flow(struct ice_hw __always_unused *hw,
+			       enum ice_fltr_ptype __always_unused flow_type)
+{
+	return false;
+}
+#endif /* CONFIG_RFS_ACCEL */
+#endif /* _ICE_ARFS_H_ */