i40e: Add code to handle FD table full condition

Add code to enforce the following policy:
- If the HW reports filter programming error, we check if it's due to a
  full table.
- If so, we go ahead and turn off new rule addition for ATR and then SB
  in that order.
- We monitor the programmed filter count, if enough room is created due
  to filter deletion/reset, we then re-enable SB and ATR new rule addition.

Change-ID: I69d24b29e5c45bc4fa861258e11c2fa7b8868748
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e.h

@@ -152,7 +152,10 @@ struct i40e_lump_tracking {
 };
 
 #define I40E_DEFAULT_ATR_SAMPLE_RATE	20
-#define I40E_FDIR_MAX_RAW_PACKET_SIZE   512
+#define I40E_FDIR_MAX_RAW_PACKET_SIZE	512
+#define I40E_FDIR_BUFFER_FULL_MARGIN	10
+#define I40E_FDIR_BUFFER_HEAD_ROOM	200
+
 struct i40e_fdir_filter {
 	struct hlist_node fdir_node;
 	/* filter ipnut set */
@@ -553,6 +556,8 @@ int i40e_program_fdir_filter(struct i40e_fdir_filter *fdir_data, u8 *raw_packet,
 			     struct i40e_pf *pf, bool add);
 int i40e_add_del_fdir(struct i40e_vsi *vsi,
 		      struct i40e_fdir_filter *input, bool add);
+void i40e_fdir_check_and_reenable(struct i40e_pf *pf);
+int i40e_get_current_fd_count(struct i40e_pf *pf);
 void i40e_set_ethtool_ops(struct net_device *netdev);
 struct i40e_mac_filter *i40e_add_filter(struct i40e_vsi *vsi,
 					u8 *macaddr, s16 vlan,

drivers/net/ethernet/intel/i40e/i40e_debugfs.c

@@ -1011,10 +1011,12 @@ static void i40e_dbg_dump_veb_all(struct i40e_pf *pf)
  **/
 static void i40e_dbg_cmd_fd_ctrl(struct i40e_pf *pf, u64 flag, bool enable)
 {
-	if (enable)
+	if (enable) {
 		pf->flags |= flag;
-	else
+	} else {
 		pf->flags &= ~flag;
+		pf->auto_disable_flags |= flag;
+	}
 	dev_info(&pf->pdev->dev, "requesting a pf reset\n");
 	i40e_do_reset_safe(pf, (1 << __I40E_PF_RESET_REQUESTED));
 }
@@ -1670,6 +1672,15 @@ static ssize_t i40e_dbg_command_write(struct file *filp,
 		bool add = false;
 		int ret;
 
+		if (!(pf->flags & I40E_FLAG_FD_SB_ENABLED))
+			goto command_write_done;
+
+		if (strncmp(cmd_buf, "add", 3) == 0)
+			add = true;
+
+		if (add && (pf->auto_disable_flags & I40E_FLAG_FD_SB_ENABLED))
+			goto command_write_done;
+
 		asc_packet = kzalloc(I40E_FDIR_MAX_RAW_PACKET_SIZE,
 				     GFP_KERNEL);
 		if (!asc_packet)
@@ -1684,8 +1695,6 @@ static ssize_t i40e_dbg_command_write(struct file *filp,
 			goto command_write_done;
 		}
 
-		if (strncmp(cmd_buf, "add", 3) == 0)
-			add = true;
 		cnt = sscanf(&cmd_buf[13],
 			     "%hx %2hhx %2hhx %hx %2hhx %2hhx %hx %x %hd %511s",
 			     &fd_data.q_index,

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -1460,6 +1460,7 @@ static int i40e_del_fdir_entry(struct i40e_vsi *vsi,
 
 	ret = i40e_update_ethtool_fdir_entry(vsi, NULL, fsp->location, cmd);
 
+	i40e_fdir_check_and_reenable(pf);
 	return ret;
 }
 
@@ -1483,9 +1484,16 @@ static int i40e_add_del_fdir_ethtool(struct i40e_vsi *vsi,
 	if (!vsi)
 		return -EINVAL;
 
-	fsp = (struct ethtool_rx_flow_spec *)&cmd->fs;
 	pf = vsi->back;
 
+	if (!(pf->flags & I40E_FLAG_FD_SB_ENABLED))
+		return -EOPNOTSUPP;
+
+	if (add && (pf->auto_disable_flags & I40E_FLAG_FD_SB_ENABLED))
+		return -ENOSPC;
+
+	fsp = (struct ethtool_rx_flow_spec *)&cmd->fs;
+
 	if (fsp->location >= (pf->hw.func_caps.fd_filters_best_effort +
 			      pf->hw.func_caps.fd_filters_guaranteed)) {
 		return -EINVAL;

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -2436,6 +2436,9 @@ static void i40e_fdir_filter_restore(struct i40e_vsi *vsi)
 	struct i40e_pf *pf = vsi->back;
 	struct hlist_node *node;
 
+	if (!(pf->flags & I40E_FLAG_FD_SB_ENABLED))
+		return;
+
 	hlist_for_each_entry_safe(filter, node,
 				  &pf->fdir_filter_list, fdir_node) {
 		i40e_add_del_fdir(vsi, filter, true);
@@ -4623,6 +4626,54 @@ static void i40e_service_event_complete(struct i40e_pf *pf)
 	clear_bit(__I40E_SERVICE_SCHED, &pf->state);
 }
 
+/**
+ * i40e_get_current_fd_count - Get the count of FD filters programmed in the HW
+ * @pf: board private structure
+ **/
+int i40e_get_current_fd_count(struct i40e_pf *pf)
+{
+	int val, fcnt_prog;
+	val = rd32(&pf->hw, I40E_PFQF_FDSTAT);
+	fcnt_prog = (val & I40E_PFQF_FDSTAT_GUARANT_CNT_MASK) +
+		    ((val & I40E_PFQF_FDSTAT_BEST_CNT_MASK) >>
+		      I40E_PFQF_FDSTAT_BEST_CNT_SHIFT);
+	return fcnt_prog;
+}
+
+/**
+ * i40e_fdir_check_and_reenable - Function to reenabe FD ATR or SB if disabled
+ * @pf: board private structure
+ **/
+void i40e_fdir_check_and_reenable(struct i40e_pf *pf)
+{
+	u32 fcnt_prog, fcnt_avail;
+
+	/* Check if, FD SB or ATR was auto disabled and if there is enough room
+	 * to re-enable
+	 */
+	if ((pf->flags & I40E_FLAG_FD_ATR_ENABLED) &&
+	    (pf->flags & I40E_FLAG_FD_SB_ENABLED))
+		return;
+	fcnt_prog = i40e_get_current_fd_count(pf);
+	fcnt_avail = pf->hw.fdir_shared_filter_count +
+					       pf->fdir_pf_filter_count;
+	if (fcnt_prog < (fcnt_avail - I40E_FDIR_BUFFER_HEAD_ROOM)) {
+		if ((pf->flags & I40E_FLAG_FD_SB_ENABLED) &&
+		    (pf->auto_disable_flags & I40E_FLAG_FD_SB_ENABLED)) {
+			pf->auto_disable_flags &= ~I40E_FLAG_FD_SB_ENABLED;
+			dev_info(&pf->pdev->dev, "FD Sideband/ntuple is being enabled since we have space in the table now\n");
+		}
+	}
+	/* Wait for some more space to be available to turn on ATR */
+	if (fcnt_prog < (fcnt_avail - I40E_FDIR_BUFFER_HEAD_ROOM * 2)) {
+		if ((pf->flags & I40E_FLAG_FD_ATR_ENABLED) &&
+		    (pf->auto_disable_flags & I40E_FLAG_FD_ATR_ENABLED)) {
+			pf->auto_disable_flags &= ~I40E_FLAG_FD_ATR_ENABLED;
+			dev_info(&pf->pdev->dev, "ATR is being enabled since we have space in the table now\n");
+		}
+	}
+}
+
 /**
  * i40e_fdir_reinit_subtask - Worker thread to reinit FDIR filter table
  * @pf: board private structure
@@ -4632,11 +4683,14 @@ static void i40e_fdir_reinit_subtask(struct i40e_pf *pf)
 	if (!(pf->flags & I40E_FLAG_FDIR_REQUIRES_REINIT))
 		return;
 
-	pf->flags &= ~I40E_FLAG_FDIR_REQUIRES_REINIT;
-
 	/* if interface is down do nothing */
 	if (test_bit(__I40E_DOWN, &pf->state))
 		return;
+	i40e_fdir_check_and_reenable(pf);
+
+	if ((pf->flags & I40E_FLAG_FD_ATR_ENABLED) &&
+	    (pf->flags & I40E_FLAG_FD_SB_ENABLED))
+		pf->flags &= ~I40E_FLAG_FDIR_REQUIRES_REINIT;
 }
 
 /**

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -430,23 +430,61 @@ int i40e_add_del_fdir(struct i40e_vsi *vsi,
 /**
  * i40e_fd_handle_status - check the Programming Status for FD
  * @rx_ring: the Rx ring for this descriptor
- * @qw: the descriptor data
+ * @rx_desc: the Rx descriptor for programming Status, not a packet descriptor.
  * @prog_id: the id originally used for programming
  *
  * This is used to verify if the FD programming or invalidation
  * requested by SW to the HW is successful or not and take actions accordingly.
  **/
-static void i40e_fd_handle_status(struct i40e_ring *rx_ring, u32 qw, u8 prog_id)
+static void i40e_fd_handle_status(struct i40e_ring *rx_ring,
+				  union i40e_rx_desc *rx_desc, u8 prog_id)
 {
-	struct pci_dev *pdev = rx_ring->vsi->back->pdev;
+	struct i40e_pf *pf = rx_ring->vsi->back;
+	struct pci_dev *pdev = pf->pdev;
+	u32 fcnt_prog, fcnt_avail;
 	u32 error;
+	u64 qw;
 
+	qw = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
 	error = (qw & I40E_RX_PROG_STATUS_DESC_QW1_ERROR_MASK) >>
 		I40E_RX_PROG_STATUS_DESC_QW1_ERROR_SHIFT;
 
-	/* for now just print the Status */
+	if (error == (0x1 << I40E_RX_PROG_STATUS_DESC_FD_TBL_FULL_SHIFT)) {
-	dev_info(&pdev->dev, "FD programming id %02x, Status %08x\n",
+		dev_warn(&pdev->dev, "ntuple filter loc = %d, could not be added\n",
-		 prog_id, error);
+			 rx_desc->wb.qword0.hi_dword.fd_id);
+
+		/* filter programming failed most likely due to table full */
+		fcnt_prog = i40e_get_current_fd_count(pf);
+		fcnt_avail = pf->hw.fdir_shared_filter_count +
+						       pf->fdir_pf_filter_count;
+
+		/* If ATR is running fcnt_prog can quickly change,
+		 * if we are very close to full, it makes sense to disable
+		 * FD ATR/SB and then re-enable it when there is room.
+		 */
+		if (fcnt_prog >= (fcnt_avail - I40E_FDIR_BUFFER_FULL_MARGIN)) {
+			/* Turn off ATR first */
+			if (pf->flags | I40E_FLAG_FD_ATR_ENABLED) {
+				pf->flags &= ~I40E_FLAG_FD_ATR_ENABLED;
+				dev_warn(&pdev->dev, "FD filter space full, ATR for further flows will be turned off\n");
+				pf->auto_disable_flags |=
+						       I40E_FLAG_FD_ATR_ENABLED;
+				pf->flags |= I40E_FLAG_FDIR_REQUIRES_REINIT;
+			} else if (pf->flags | I40E_FLAG_FD_SB_ENABLED) {
+				pf->flags &= ~I40E_FLAG_FD_SB_ENABLED;
+				dev_warn(&pdev->dev, "FD filter space full, new ntuple rules will not be added\n");
+				pf->auto_disable_flags |=
+							I40E_FLAG_FD_SB_ENABLED;
+				pf->flags |= I40E_FLAG_FDIR_REQUIRES_REINIT;
+			}
+		} else {
+			dev_info(&pdev->dev, "FD filter programming error");
+		}
+	} else if (error ==
+			  (0x1 << I40E_RX_PROG_STATUS_DESC_NO_FD_ENTRY_SHIFT)) {
+		netdev_info(rx_ring->vsi->netdev, "ntuple filter loc = %d, could not be removed\n",
+			    rx_desc->wb.qword0.hi_dword.fd_id);
+	}
 }
 
 /**
@@ -843,7 +881,7 @@ static void i40e_clean_programming_status(struct i40e_ring *rx_ring,
 		  I40E_RX_PROG_STATUS_DESC_QW1_PROGID_SHIFT;
 
 	if (id == I40E_RX_PROG_STATUS_DESC_FD_FILTER_STATUS)
-		i40e_fd_handle_status(rx_ring, qw, id);
+		i40e_fd_handle_status(rx_ring, rx_desc, id);
 }
 
 /**
@@ -1536,8 +1574,6 @@ static void i40e_atr(struct i40e_ring *tx_ring, struct sk_buff *skb,
 	if (!tx_ring->atr_sample_rate)
 		return;
 
-	tx_ring->atr_count++;
-
 	/* snag network header to get L4 type and address */
 	hdr.network = skb_network_header(skb);
 
@@ -1559,6 +1595,12 @@ static void i40e_atr(struct i40e_ring *tx_ring, struct sk_buff *skb,
 
 	th = (struct tcphdr *)(hdr.network + hlen);
 
+	/* Due to lack of space, no more new filters can be programmed */
+	if (th->syn && (pf->auto_disable_flags & I40E_FLAG_FD_ATR_ENABLED))
+		return;
+
+	tx_ring->atr_count++;
+
 	/* sample on all syn/fin packets or once every atr sample rate */
 	if (!th->fin && !th->syn && (tx_ring->atr_count < tx_ring->atr_sample_rate))
 		return;