From: Michael Chan <michael.chan@broadcom.com>
Date: Fri, 13 Oct 2017 21:09:29 -0400
Subject: bnxt_en: Improve VF/PF link change logic.
Patch-mainline: v4.14-rc6
Git-commit: c213eae8d3cd4c026f348ce4fd64f4754b3acf2b
References: bsc#1050242 FATE#322914

Link status query firmware messages originating from the VFs are forwarded
to the PF.  The driver handles these interactions in a workqueue for the
VF and PF.  The VF driver waits for the response from the PF in the
workqueue.  If the PF and VF driver are running on the same host and the
work for both PF and VF are queued on the same workqueue, the VF driver
may not get the response if the PF work item is queued behind it on the
same workqueue.  This will lead to the VF link query message timing out.

To prevent this, we create a private workqueue for PFs instead of using
the common workqueue.  The VF query and PF response will never be on
the same workqueue.

Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c |   66 ++++++++++++++++++++++++------
 1 file changed, 53 insertions(+), 13 deletions(-)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -214,6 +214,8 @@ static const u16 bnxt_async_events_arr[]
 	ASYNC_EVENT_CMPL_EVENT_ID_LINK_SPEED_CFG_CHANGE,
 };
 
+static struct workqueue_struct *bnxt_pf_wq;
+
 static bool bnxt_vf_pciid(enum board_idx idx)
 {
 	return (idx == NETXTREME_C_VF || idx == NETXTREME_E_VF);
@@ -1024,12 +1026,28 @@ static int bnxt_discard_rx(struct bnxt *
 	return 0;
 }
 
+static void bnxt_queue_sp_work(struct bnxt *bp)
+{
+	if (BNXT_PF(bp))
+		queue_work(bnxt_pf_wq, &bp->sp_task);
+	else
+		schedule_work(&bp->sp_task);
+}
+
+static void bnxt_cancel_sp_work(struct bnxt *bp)
+{
+	if (BNXT_PF(bp))
+		flush_workqueue(bnxt_pf_wq);
+	else
+		cancel_work_sync(&bp->sp_task);
+}
+
 static void bnxt_sched_reset(struct bnxt *bp, struct bnxt_rx_ring_info *rxr)
 {
 	if (!rxr->bnapi->in_reset) {
 		rxr->bnapi->in_reset = true;
 		set_bit(BNXT_RESET_TASK_SP_EVENT, &bp->sp_event);
-		schedule_work(&bp->sp_task);
+		bnxt_queue_sp_work(bp);
 	}
 	rxr->rx_next_cons = 0xffff;
 }
@@ -1717,7 +1735,7 @@ static int bnxt_async_event_process(stru
 	default:
 		goto async_event_process_exit;
 	}
-	schedule_work(&bp->sp_task);
+	bnxt_queue_sp_work(bp);
 async_event_process_exit:
 	bnxt_ulp_async_events(bp, cmpl);
 	return 0;
@@ -1751,7 +1769,7 @@ static int bnxt_hwrm_handler(struct bnxt
 
 		set_bit(vf_id - bp->pf.first_vf_id, bp->pf.vf_event_bmap);
 		set_bit(BNXT_HWRM_EXEC_FWD_REQ_SP_EVENT, &bp->sp_event);
-		schedule_work(&bp->sp_task);
+		bnxt_queue_sp_work(bp);
 		break;
 
 	case CMPL_BASE_TYPE_HWRM_ASYNC_EVENT:
@@ -6647,7 +6665,7 @@ static void bnxt_set_rx_mode(struct net_
 		vnic->rx_mask = mask;
 
 		set_bit(BNXT_RX_MASK_SP_EVENT, &bp->sp_event);
-		schedule_work(&bp->sp_task);
+		bnxt_queue_sp_work(bp);
 	}
 }
 
@@ -6920,7 +6938,7 @@ static void bnxt_tx_timeout(struct net_d
 
 	netdev_err(bp->dev,  "TX timeout detected, starting reset task!\n");
 	set_bit(BNXT_RESET_TASK_SP_EVENT, &bp->sp_event);
-	schedule_work(&bp->sp_task);
+	bnxt_queue_sp_work(bp);
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -6952,7 +6970,7 @@ static void bnxt_timer(unsigned long dat
 	if (bp->link_info.link_up && (bp->flags & BNXT_FLAG_PORT_STATS) &&
 	    bp->stats_coal_ticks) {
 		set_bit(BNXT_PERIODIC_STATS_SP_EVENT, &bp->sp_event);
-		schedule_work(&bp->sp_task);
+		bnxt_queue_sp_work(bp);
 	}
 bnxt_restart_timer:
 	mod_timer(&bp->timer, jiffies + bp->current_interval);
@@ -7433,7 +7451,7 @@ static int bnxt_rx_flow_steer(struct net
 	spin_unlock_bh(&bp->ntp_fltr_lock);
 
 	set_bit(BNXT_RX_NTP_FLTR_SP_EVENT, &bp->sp_event);
-	schedule_work(&bp->sp_task);
+	bnxt_queue_sp_work(bp);
 
 	return new_fltr->sw_id;
 
@@ -7516,7 +7534,7 @@ static void bnxt_udp_tunnel_add(struct n
 		if (bp->vxlan_port_cnt == 1) {
 			bp->vxlan_port = ti->port;
 			set_bit(BNXT_VXLAN_ADD_PORT_SP_EVENT, &bp->sp_event);
-			schedule_work(&bp->sp_task);
+			bnxt_queue_sp_work(bp);
 		}
 		break;
 	case UDP_TUNNEL_TYPE_GENEVE:
@@ -7533,7 +7551,7 @@ static void bnxt_udp_tunnel_add(struct n
 		return;
 	}
 
-	schedule_work(&bp->sp_task);
+	bnxt_queue_sp_work(bp);
 }
 
 static void bnxt_udp_tunnel_del(struct net_device *dev,
@@ -7572,7 +7590,7 @@ static void bnxt_udp_tunnel_del(struct n
 		return;
 	}
 
-	schedule_work(&bp->sp_task);
+	bnxt_queue_sp_work(bp);
 }
 
 static int bnxt_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
@@ -7720,7 +7738,7 @@ static void bnxt_remove_one(struct pci_d
 	pci_disable_pcie_error_reporting(pdev);
 	unregister_netdev(dev);
 	bnxt_shutdown_tc(bp);
-	cancel_work_sync(&bp->sp_task);
+	bnxt_cancel_sp_work(bp);
 	bp->sp_event = 0;
 
 	bnxt_clear_int_mode(bp);
@@ -8138,8 +8156,17 @@ static int bnxt_init_one(struct pci_dev
 	else
 		device_set_wakeup_capable(&pdev->dev, false);
 
-	if (BNXT_PF(bp))
+	if (BNXT_PF(bp)) {
+		if (!bnxt_pf_wq) {
+			bnxt_pf_wq =
+				create_singlethread_workqueue("bnxt_pf_wq");
+			if (!bnxt_pf_wq) {
+				dev_err(&pdev->dev, "Unable to create workqueue.\n");
+				goto init_err_pci_clean;
+			}
+		}
 		bnxt_init_tc(bp);
+	}
 
 	rc = register_netdev(dev);
 	if (rc)
@@ -8375,4 +8402,17 @@ static struct pci_driver bnxt_pci_driver
 #endif
 };
 
-module_pci_driver(bnxt_pci_driver);
+static int __init bnxt_init(void)
+{
+	return pci_register_driver(&bnxt_pci_driver);
+}
+
+static void __exit bnxt_exit(void)
+{
+	pci_unregister_driver(&bnxt_pci_driver);
+	if (bnxt_pf_wq)
+		destroy_workqueue(bnxt_pf_wq);
+}
+
+module_init(bnxt_init);
+module_exit(bnxt_exit);