net: thunderx: move link state polling function to VF [Linux 5.0]

net: thunderx: move link state polling function to VF [Linux 5.0]

This Linux kernel change "net: thunderx: move link state polling function to VF" is included in the Linux 5.0 release. This change is authored by Vadim Lomovtsev <vlomovtsev [at] marvell.com> on Wed Feb 20 11:02:45 2019 +0000. The commit for this change in Linux stable tree is 2c632ad (patch).

net: thunderx: move link state polling function to VF

Move the link change polling task to VF side in order to
prevent races between VF and PF while sending link change
message(s). This commit is to implement link change request
to be initiated by VF.

Signed-off-by: Vadim Lomovtsev <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

There are 93 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/net/ethernet/cavium/thunder/nic.h        |  2 +-
 drivers/net/ethernet/cavium/thunder/nic_main.c   | 39 ++++++++++++++++--
 drivers/net/ethernet/cavium/thunder/nicvf_main.c | 52 +++++++++++++++++-------
 3 files changed, 74 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/cavium/thunder/nic.h b/drivers/net/ethernet/cavium/thunder/nic.h
index 86cda3f..62636c1 100644
--- a/drivers/net/ethernet/cavium/thunder/nic.h
+++ b/drivers/net/ethernet/cavium/thunder/nic.h
@@ -331,7 +331,7 @@ struct nicvf {
    struct workqueue_struct *nicvf_rx_mode_wq;
    /* mutex to protect VF's mailbox contents from concurrent access */
    struct mutex            rx_mode_mtx;
-
+   struct delayed_work link_change_work;
    /* PTP timestamp */
    struct cavium_ptp   *ptp_clock;
    /* Inbound timestamping is on */
diff --git a/drivers/net/ethernet/cavium/thunder/nic_main.c b/drivers/net/ethernet/cavium/thunder/nic_main.c
index 620dbe0..8ab71da 100644
--- a/drivers/net/ethernet/cavium/thunder/nic_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nic_main.c
@@ -929,6 +929,35 @@ static void nic_config_timestamp(struct nicpf *nic, int vf, struct set_ptp *ptp)
    nic_reg_write(nic, NIC_PF_PKIND_0_15_CFG | (pkind_idx << 3), pkind_val);
 }

+static void nic_link_status_get(struct nicpf *nic, u8 vf)
+{
+   union nic_mbx mbx = {};
+   struct bgx_link_status link;
+   u8 bgx, lmac;
+
+   mbx.link_status.msg = NIC_MBOX_MSG_BGX_LINK_CHANGE;
+
+   /* Get BGX, LMAC indices for the VF */
+   bgx = NIC_GET_BGX_FROM_VF_LMAC_MAP(nic->vf_lmac_map[vf]);
+   lmac = NIC_GET_LMAC_FROM_VF_LMAC_MAP(nic->vf_lmac_map[vf]);
+
+   /* Get interface link status */
+   bgx_get_lmac_link_state(nic->node, bgx, lmac, &link);
+
+   nic->link[vf] = link.link_up;
+   nic->duplex[vf] = link.duplex;
+   nic->speed[vf] = link.speed;
+
+   /* Send a mbox message to VF with current link status */
+   mbx.link_status.link_up = link.link_up;
+   mbx.link_status.duplex = link.duplex;
+   mbx.link_status.speed = link.speed;
+   mbx.link_status.mac_type = link.mac_type;
+
+   /* reply with link status */
+   nic_send_msg_to_vf(nic, vf, &mbx);
+}
+
 /* Interrupt handler to handle mailbox messages from VFs */
 static void nic_handle_mbx_intr(struct nicpf *nic, int vf)
 {
@@ -1108,6 +1137,13 @@ static void nic_handle_mbx_intr(struct nicpf *nic, int vf)
        lmac = NIC_GET_LMAC_FROM_VF_LMAC_MAP(nic->vf_lmac_map[vf]);
        bgx_set_xcast_mode(nic->node, bgx, lmac, mbx.xcast.mode);
        break;
+   case NIC_MBOX_MSG_BGX_LINK_CHANGE:
+       if (vf >= nic->num_vf_en) {
+           ret = -1; /* NACK */
+           break;
+       }
+       nic_link_status_get(nic, vf);
+       goto unlock;
    default:
        dev_err(&nic->pdev->dev,
            "Invalid msg from VF%d, msg 0x%x\n", vf, mbx.msg.msg);
@@ -1419,9 +1455,6 @@ static int nic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
        goto err_disable_sriov;
    }

-   INIT_DELAYED_WORK(&nic->dwork, nic_poll_for_link);
-   queue_delayed_work(nic->check_link, &nic->dwork, 0);
-
    return 0;

 err_disable_sriov:
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 2332e3e..503cfad 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -242,21 +242,24 @@ static void  nicvf_handle_mbx_intr(struct nicvf *nic)
        break;
    case NIC_MBOX_MSG_BGX_LINK_CHANGE:
        nic->pf_acked = true;
-       nic->link_up = mbx.link_status.link_up;
-       nic->duplex = mbx.link_status.duplex;
-       nic->speed = mbx.link_status.speed;
-       nic->mac_type = mbx.link_status.mac_type;
-       if (nic->link_up) {
-           netdev_info(nic->netdev, "Link is Up %d Mbps %s duplex\n",
-                   nic->speed,
-                   nic->duplex == DUPLEX_FULL ?
-                   "Full" : "Half");
-           netif_carrier_on(nic->netdev);
-           netif_tx_start_all_queues(nic->netdev);
-       } else {
-           netdev_info(nic->netdev, "Link is Down\n");
-           netif_carrier_off(nic->netdev);
-           netif_tx_stop_all_queues(nic->netdev);
+       if (nic->link_up != mbx.link_status.link_up) {
+           nic->link_up = mbx.link_status.link_up;
+           nic->duplex = mbx.link_status.duplex;
+           nic->speed = mbx.link_status.speed;
+           nic->mac_type = mbx.link_status.mac_type;
+           if (nic->link_up) {
+               netdev_info(nic->netdev,
+                       "Link is Up %d Mbps %s duplex\n",
+                       nic->speed,
+                       nic->duplex == DUPLEX_FULL ?
+                       "Full" : "Half");
+               netif_carrier_on(nic->netdev);
+               netif_tx_start_all_queues(nic->netdev);
+           } else {
+               netdev_info(nic->netdev, "Link is Down\n");
+               netif_carrier_off(nic->netdev);
+               netif_tx_stop_all_queues(nic->netdev);
+           }
        }
        break;
    case NIC_MBOX_MSG_ALLOC_SQS:
@@ -1325,6 +1328,8 @@ int nicvf_stop(struct net_device *netdev)
    struct nicvf_cq_poll *cq_poll = NULL;
    union nic_mbx mbx = {};

+   cancel_delayed_work_sync(&nic->link_change_work);
+
    /* wait till all queued set_rx_mode tasks completes */
    drain_workqueue(nic->nicvf_rx_mode_wq);

@@ -1427,6 +1432,18 @@ static int nicvf_update_hw_max_frs(struct nicvf *nic, int mtu)
    return nicvf_send_msg_to_pf(nic, &mbx);
 }

+static void nicvf_link_status_check_task(struct work_struct *work_arg)
+{
+   struct nicvf *nic = container_of(work_arg,
+                    struct nicvf,
+                    link_change_work.work);
+   union nic_mbx mbx = {};
+   mbx.msg.msg = NIC_MBOX_MSG_BGX_LINK_CHANGE;
+   nicvf_send_msg_to_pf(nic, &mbx);
+   queue_delayed_work(nic->nicvf_rx_mode_wq,
+              &nic->link_change_work, 2 * HZ);
+}
+
 int nicvf_open(struct net_device *netdev)
 {
    int cpu, err, qidx;
@@ -1533,6 +1550,11 @@ int nicvf_open(struct net_device *netdev)
    /* Send VF config done msg to PF */
    nicvf_send_cfg_done(nic);

+   INIT_DELAYED_WORK(&nic->link_change_work,
+             nicvf_link_status_check_task);
+   queue_delayed_work(nic->nicvf_rx_mode_wq,
+              &nic->link_change_work, 0);
+
    return 0;
 cleanup:
    nicvf_disable_intr(nic, NICVF_INTR_MBOX, 0);

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