[PATCH net-next v14 4/5] net: wangxun: implement soft quiesce for PCIe error recovery

[Jiawen Wu <jiawenwu@trustnetic.com>]

Function wx_soft_quiesce() provide a lightweight shutdown path during
PCIe error recovery. It avoids MMIO-dependent operations in PCIe error
status.

Waiting for the service task to complete may unnecessarily delay PCIe
error recovery, especially if the work item is already blocked by the
hardware failure that triggered AER. So the service task is not
explicitly cancelled in quiesce path. As a measure to block the service
task, the checking of WX_STATE_DOWN and WX_STATE_RESETTING is added at
the entry of relevant work item.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
---
 drivers/net/ethernet/wangxun/libwx/wx_lib.c   | 18 +++++++++++++
 drivers/net/ethernet/wangxun/libwx/wx_lib.h   |  1 +
 drivers/net/ethernet/wangxun/libwx/wx_ptp.c   | 27 +++++++++++++++++++
 drivers/net/ethernet/wangxun/libwx/wx_ptp.h   |  1 +
 .../net/ethernet/wangxun/txgbe/txgbe_main.c   | 16 +++++++++++
 5 files changed, 63 insertions(+)

diff --git a/drivers/net/ethernet/wangxun/libwx/wx_lib.c b/drivers/net/ethernet/wangxun/libwx/wx_lib.c
index 67af8640a49e..ed5aad7857bd 100644
--- a/drivers/net/ethernet/wangxun/libwx/wx_lib.c
+++ b/drivers/net/ethernet/wangxun/libwx/wx_lib.c
@@ -3410,5 +3410,23 @@ void wx_service_timer(struct timer_list *t)
 }
 EXPORT_SYMBOL(wx_service_timer);
 
+void wx_soft_quiesce(struct wx *wx)
+{
+	if (!netif_running(wx->netdev) ||
+	    test_and_set_bit(WX_STATE_DOWN, wx->state))
+		return;
+
+	pci_clear_master(wx->pdev);
+	netif_tx_stop_all_queues(wx->netdev);
+	netif_carrier_off(wx->netdev);
+	netif_tx_disable(wx->netdev);
+	wx_napi_disable_all(wx);
+	wx_ptp_quiesce(wx);
+
+	clear_bit(WX_FLAG_NEED_DO_RESET, wx->flags);
+	timer_delete_sync(&wx->service_timer);
+}
+EXPORT_SYMBOL(wx_soft_quiesce);
+
 MODULE_DESCRIPTION("Common library for Wangxun(R) Ethernet drivers.");
 MODULE_LICENSE("GPL");
diff --git a/drivers/net/ethernet/wangxun/libwx/wx_lib.h b/drivers/net/ethernet/wangxun/libwx/wx_lib.h
index bc671786978e..9d85d399e17f 100644
--- a/drivers/net/ethernet/wangxun/libwx/wx_lib.h
+++ b/drivers/net/ethernet/wangxun/libwx/wx_lib.h
@@ -41,5 +41,6 @@ int wx_set_ring(struct wx *wx, u32 new_tx_count,
 void wx_service_event_schedule(struct wx *wx);
 void wx_service_event_complete(struct wx *wx);
 void wx_service_timer(struct timer_list *t);
+void wx_soft_quiesce(struct wx *wx);
 
 #endif /* _WX_LIB_H_ */
diff --git a/drivers/net/ethernet/wangxun/libwx/wx_ptp.c b/drivers/net/ethernet/wangxun/libwx/wx_ptp.c
index 44f3e6505246..3eea647c4742 100644
--- a/drivers/net/ethernet/wangxun/libwx/wx_ptp.c
+++ b/drivers/net/ethernet/wangxun/libwx/wx_ptp.c
@@ -321,6 +321,9 @@ static long wx_ptp_do_aux_work(struct ptp_clock_info *ptp)
 	struct wx *wx = container_of(ptp, struct wx, ptp_caps);
 	int ts_done;
 
+	if (!test_bit(WX_STATE_PTP_RUNNING, wx->state))
+		return HZ;
+
 	ts_done = wx_ptp_tx_hwtstamp_work(wx);
 
 	wx_ptp_overflow_check(wx);
@@ -842,6 +845,30 @@ void wx_ptp_stop(struct wx *wx)
 }
 EXPORT_SYMBOL(wx_ptp_stop);
 
+void wx_ptp_quiesce(struct wx *wx)
+{
+	if (!test_and_clear_bit(WX_STATE_PTP_RUNNING, wx->state))
+		return;
+
+	clear_bit(WX_FLAG_PTP_PPS_ENABLED, wx->flags);
+
+	if (wx->ptp_clock)
+		ptp_cancel_worker_sync(wx->ptp_clock);
+
+	if (wx->ptp_tx_skb) {
+		dev_kfree_skb_any(wx->ptp_tx_skb);
+		wx->ptp_tx_skb = NULL;
+	}
+	clear_bit_unlock(WX_STATE_PTP_TX_IN_PROGRESS, wx->state);
+
+	if (wx->ptp_clock) {
+		ptp_clock_unregister(wx->ptp_clock);
+		wx->ptp_clock = NULL;
+		dev_info(&wx->pdev->dev, "removed PHC on %s\n", wx->netdev->name);
+	}
+}
+EXPORT_SYMBOL(wx_ptp_quiesce);
+
 /**
  * wx_ptp_rx_hwtstamp - utility function which checks for RX time stamp
  * @wx: pointer to wx struct
diff --git a/drivers/net/ethernet/wangxun/libwx/wx_ptp.h b/drivers/net/ethernet/wangxun/libwx/wx_ptp.h
index 50db90a6e3ee..ad2f824875d5 100644
--- a/drivers/net/ethernet/wangxun/libwx/wx_ptp.h
+++ b/drivers/net/ethernet/wangxun/libwx/wx_ptp.h
@@ -10,6 +10,7 @@ void wx_ptp_reset(struct wx *wx);
 void wx_ptp_init(struct wx *wx);
 void wx_ptp_suspend(struct wx *wx);
 void wx_ptp_stop(struct wx *wx);
+void wx_ptp_quiesce(struct wx *wx);
 void wx_ptp_rx_hwtstamp(struct wx *wx, struct sk_buff *skb);
 int wx_hwtstamp_get(struct net_device *dev,
 		    struct kernel_hwtstamp_config *cfg);
diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
index f25249ddf2c6..414b2ba8dfc4 100644
--- a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
+++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
@@ -94,12 +94,24 @@ static void txgbe_module_detection_subtask(struct wx *wx)
 {
 	int err;
 
+	if (test_bit(WX_STATE_DOWN, wx->state) ||
+	    test_bit(WX_STATE_RESETTING, wx->state))
+		return;
+
 	if (!test_and_clear_bit(WX_FLAG_NEED_MODULE_RESET, wx->flags))
 		return;
 
 	/* wait for SFF module ready */
 	msleep(200);
 
+	/* Re-check state to avoid racing with down/reset paths.
+	 * Module identification is deferred to the next up event,
+	 * so it is safe to bail out here.
+	 */
+	if (test_bit(WX_STATE_DOWN, wx->state) ||
+	    test_bit(WX_STATE_RESETTING, wx->state))
+		return;
+
 	err = txgbe_identify_module(wx);
 	if (err == -ENODEV)
 		set_bit(WX_FLAG_NEED_MODULE_RESET, wx->flags);
@@ -107,6 +119,10 @@ static void txgbe_module_detection_subtask(struct wx *wx)
 
 static void txgbe_link_config_subtask(struct wx *wx)
 {
+	if (test_bit(WX_STATE_DOWN, wx->state) ||
+	    test_bit(WX_STATE_RESETTING, wx->state))
+		return;
+
 	if (!test_and_clear_bit(WX_FLAG_NEED_LINK_CONFIG, wx->flags))
 		return;
 
-- 
2.51.0