ice: Don't reset and rebuild for Tx timeout on PFC enabled queue

When there's a Tx timeout for a queue which belongs to a PFC enabled TC,
then it's not because the queue is hung but because PFC is in action.

In PFC, peer sends a pause frame for a specified period of time when its
buffer threshold is exceeded (due to congestion). Netdev on the other
hand checks if ACK is received within a specified time for a TX packet, if
not, it'll invoke the tx_timeout routine.

Signed-off-by: Avinash JD <avinash.dayanand@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>

diff --git a/drivers/net/ethernet/intel/ice/ice_dcb_lib.c b/drivers/net/ethernet/intel/ice/ice_dcb_lib.c
index 7bea093..448b7d2 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_dcb_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_dcb_lib.c
@@ -63,6 +63,64 @@ u8 ice_dcb_get_ena_tc(struct ice_dcbx_cfg *dcbcfg)
 }
 
 /**
+ * ice_is_pfc_causing_hung_q
+ * @pf: pointer to PF structure
+ * @txqueue: Tx queue which is supposedly hung queue
+ *
+ * find if PFC is causing the hung queue, if yes return true else false
+ */
+bool ice_is_pfc_causing_hung_q(struct ice_pf *pf, unsigned int txqueue)
+{
+       u8 num_tcs = 0, i, tc, up_mapped_tc, up_in_tc = 0;
+       u64 ref_prio_xoff[ICE_MAX_UP];
+       struct ice_vsi *vsi;
+       u32 up2tc;
+
+       vsi = ice_get_main_vsi(pf);
+       if (!vsi)
+               return false;
+
+       ice_for_each_traffic_class(i)
+               if (vsi->tc_cfg.ena_tc & BIT(i))
+                       num_tcs++;
+
+       /* first find out the TC to which the hung queue belongs to */
+       for (tc = 0; tc < num_tcs - 1; tc++)
+               if (ice_find_q_in_range(vsi->tc_cfg.tc_info[tc].qoffset,
+                                       vsi->tc_cfg.tc_info[tc + 1].qoffset,
+                                       txqueue))
+                       break;
+
+       /* Build a bit map of all UPs associated to the suspect hung queue TC,
+        * so that we check for its counter increment.
+        */
+       up2tc = rd32(&pf->hw, PRTDCB_TUP2TC);
+       for (i = 0; i < ICE_MAX_UP; i++) {
+               up_mapped_tc = (up2tc >> (i * 3)) & 0x7;
+               if (up_mapped_tc == tc)
+                       up_in_tc |= BIT(i);
+       }
+
+       /* Now that we figured out that hung queue is PFC enabled, still the
+        * Tx timeout can be legitimate. So to make sure Tx timeout is
+        * absolutely caused by PFC storm, check if the counters are
+        * incrementing.
+        */
+       for (i = 0; i < ICE_MAX_UP; i++)
+               if (up_in_tc & BIT(i))
+                       ref_prio_xoff[i] = pf->stats.priority_xoff_rx[i];
+
+       ice_update_dcb_stats(pf);
+
+       for (i = 0; i < ICE_MAX_UP; i++)
+               if (up_in_tc & BIT(i))
+                       if (pf->stats.priority_xoff_rx[i] > ref_prio_xoff[i])
+                               return true;
+
+       return false;
+}
+
+/**
  * ice_dcb_get_mode - gets the DCB mode
  * @port_info: pointer to port info structure
  * @host: if set it's HOST if not it's MANAGED

diff --git a/drivers/net/ethernet/intel/ice/ice_dcb_lib.h b/drivers/net/ethernet/intel/ice/ice_dcb_lib.h
index 37680e8..7c42324 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_dcb_lib.h
+++ b/drivers/net/ethernet/intel/ice/ice_dcb_lib.h
@@ -17,6 +17,8 @@
 void ice_dcb_rebuild(struct ice_pf *pf);
 u8 ice_dcb_get_ena_tc(struct ice_dcbx_cfg *dcbcfg);
 u8 ice_dcb_get_num_tc(struct ice_dcbx_cfg *dcbcfg);
+void ice_vsi_set_dcb_tc_cfg(struct ice_vsi *vsi);
+bool ice_is_pfc_causing_hung_q(struct ice_pf *pf, unsigned int txqueue);
 u8 ice_dcb_get_tc(struct ice_vsi *vsi, int queue_index);
 int
 ice_pf_dcb_cfg(struct ice_pf *pf, struct ice_dcbx_cfg *new_cfg, bool locked);
@@ -32,6 +34,20 @@ void
 ice_dcb_process_lldp_set_mib_change(struct ice_pf *pf,
                                    struct ice_rq_event_info *event);
 void ice_vsi_cfg_netdev_tc(struct ice_vsi *vsi, u8 ena_tc);
+
+/**
+ * ice_find_q_in_range
+ * @low: start of queue range for a TC i.e. offset of TC
+ * @high: start of queue for next TC
+ * @tx_q: hung_queue/tx_queue
+ *
+ * finds if queue 'tx_q' falls between the two offsets of any given TC
+ */
+static inline bool ice_find_q_in_range(u16 low, u16 high, unsigned int tx_q)
+{
+       return (tx_q >= low) && (tx_q < high);
+}
+
 static inline void
 ice_set_cgd_num(struct ice_tlan_ctx *tlan_ctx, struct ice_ring *ring)
 {
@@ -79,6 +95,13 @@ ice_tx_prepare_vlan_flags_dcb(struct ice_ring __always_unused *tx_ring,
        return 0;
 }
 
+static inline bool
+ice_is_pfc_causing_hung_q(struct ice_pf __always_unused *pf,
+                         unsigned int __always_unused txqueue)
+{
+       return false;
+}
+
 #define ice_update_dcb_stats(pf) do {} while (0)
 #define ice_pf_dcb_recfg(pf) do {} while (0)
 #define ice_vsi_cfg_dcb_rings(vsi) do {} while (0)

diff --git a/drivers/net/ethernet/intel/ice/ice_hw_autogen.h b/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
index 1d37a9f..bc48eda 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
+++ b/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
@@ -58,6 +58,7 @@
 #define PRTDCB_GENS                            0x00083020
 #define PRTDCB_GENS_DCBX_STATUS_S              0
 #define PRTDCB_GENS_DCBX_STATUS_M              ICE_M(0x7, 0)
+#define PRTDCB_TUP2TC                          0x001D26C0 /* Reset Source: CORER */
 #define GL_PREEXT_L2_PMASK0(_i)                        (0x0020F0FC + ((_i) * 4))
 #define GL_PREEXT_L2_PMASK1(_i)                        (0x0020F108 + ((_i) * 4))
 #define GLFLXP_RXDID_FLX_WRD_0(_i)             (0x0045c800 + ((_i) * 4))

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 44ff4fe..8c792ec 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -5114,6 +5114,16 @@ static void ice_tx_timeout(struct net_device *netdev, unsigned int txqueue)
 
        pf->tx_timeout_count++;
 
+       /* Check if PFC is enabled for the TC to which the queue belongs
+        * to. If yes then Tx timeout is not caused by a hung queue, no
+        * need to reset and rebuild
+        */
+       if (ice_is_pfc_causing_hung_q(pf, txqueue)) {
+               dev_info(ice_pf_to_dev(pf), "Fake Tx hang detected on queue %u, timeout caused by PFC storm\n",
+                        txqueue);
+               return;
+       }
+
        /* now that we have an index, find the tx_ring struct */
        for (i = 0; i < vsi->num_txq; i++)
                if (vsi->tx_rings[i] && vsi->tx_rings[i]->desc)

diff --git a/drivers/net/ethernet/intel/ice/ice_type.h b/drivers/net/ethernet/intel/ice/ice_type.h
index c56b2e7..4f5345a 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_type.h
+++ b/drivers/net/ethernet/intel/ice/ice_type.h
@@ -607,6 +607,8 @@ struct ice_eth_stats {
        u64 tx_errors;                  /* tepc */
 };
 
+#define ICE_MAX_UP     8
+
 /* Statistics collected by the MAC */
 struct ice_hw_port_stats {
        /* eth stats collected by the port */