Merge branch 'there-are-some-bugfix-for-hibmcge-ethernet-driver'

Jijie Shao says:

====================
There are some bugfix for hibmcge ethernet driver

This patch set is intended to fix several issues for hibmcge driver:
1. Holding the rtnl_lock in pci_error_handlers->reset_prepare()
   may lead to a deadlock issue.
   2. A division by zero issue caused by debugfs when the port is down.
   3. A probabilistic false positive issue with np_link_fail.

v2: https://lore.kernel.org/[email protected]
v1: https://lore.kernel.org/[email protected]
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c

@@ -53,9 +53,11 @@ static int hbg_reset_prepare(struct hbg_priv *priv, enum hbg_reset_type type)
 {
 	int ret;
 
-	ASSERT_RTNL();
+	if (test_and_set_bit(HBG_NIC_STATE_RESETTING, &priv->state))
+		return -EBUSY;
 
 	if (netif_running(priv->netdev)) {
+		clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
 		dev_warn(&priv->pdev->dev,
 			 "failed to reset because port is up\n");
 		return -EBUSY;
@@ -64,7 +66,6 @@ static int hbg_reset_prepare(struct hbg_priv *priv, enum hbg_reset_type type)
 	netif_device_detach(priv->netdev);
 
 	priv->reset_type = type;
-	set_bit(HBG_NIC_STATE_RESETTING, &priv->state);
 	clear_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
 	ret = hbg_hw_event_notify(priv, HBG_HW_EVENT_RESET);
 	if (ret) {
@@ -84,29 +85,26 @@ static int hbg_reset_done(struct hbg_priv *priv, enum hbg_reset_type type)
 	    type != priv->reset_type)
 		return 0;
 
-	ASSERT_RTNL();
-
-	clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
 	ret = hbg_rebuild(priv);
 	if (ret) {
 		priv->stats.reset_fail_cnt++;
 		set_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
+		clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
 		dev_err(&priv->pdev->dev, "failed to rebuild after reset\n");
 		return ret;
 	}
 
 	netif_device_attach(priv->netdev);
+	clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
 
 	dev_info(&priv->pdev->dev, "reset done\n");
 	return ret;
 }
 
-/* must be protected by rtnl lock */
 int hbg_reset(struct hbg_priv *priv)
 {
 	int ret;
 
-	ASSERT_RTNL();
 	ret = hbg_reset_prepare(priv, HBG_RESET_TYPE_FUNCTION);
 	if (ret)
 		return ret;
@@ -171,7 +169,6 @@ static void hbg_pci_err_reset_prepare(struct pci_dev *pdev)
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct hbg_priv *priv = netdev_priv(netdev);
 
-	rtnl_lock();
 	hbg_reset_prepare(priv, HBG_RESET_TYPE_FLR);
 }
 
@@ -181,7 +178,6 @@ static void hbg_pci_err_reset_done(struct pci_dev *pdev)
 	struct hbg_priv *priv = netdev_priv(netdev);
 
 	hbg_reset_done(priv, HBG_RESET_TYPE_FLR);
-	rtnl_unlock();
 }
 
 static const struct pci_error_handlers hbg_pci_err_handler = {

drivers/net/ethernet/hisilicon/hibmcge/hbg_hw.c

@@ -12,6 +12,8 @@
 
 #define HBG_HW_EVENT_WAIT_TIMEOUT_US	(2 * 1000 * 1000)
 #define HBG_HW_EVENT_WAIT_INTERVAL_US	(10 * 1000)
+#define HBG_MAC_LINK_WAIT_TIMEOUT_US	(500 * 1000)
+#define HBG_MAC_LINK_WAIT_INTERVAL_US	(5 * 1000)
 /* little endian or big endian.
  * ctrl means packet description, data means skb packet data
  */
@@ -228,6 +230,9 @@ void hbg_hw_fill_buffer(struct hbg_priv *priv, u32 buffer_dma_addr)
 
 void hbg_hw_adjust_link(struct hbg_priv *priv, u32 speed, u32 duplex)
 {
+	u32 link_status;
+	int ret;
+
 	hbg_hw_mac_enable(priv, HBG_STATUS_DISABLE);
 
 	hbg_reg_write_field(priv, HBG_REG_PORT_MODE_ADDR,
@@ -239,8 +244,14 @@ void hbg_hw_adjust_link(struct hbg_priv *priv, u32 speed, u32 duplex)
 
 	hbg_hw_mac_enable(priv, HBG_STATUS_ENABLE);
 
-	if (!hbg_reg_read_field(priv, HBG_REG_AN_NEG_STATE_ADDR,
-				HBG_REG_AN_NEG_STATE_NP_LINK_OK_B))
+	/* wait MAC link up */
+	ret = readl_poll_timeout(priv->io_base + HBG_REG_AN_NEG_STATE_ADDR,
+				 link_status,
+				 FIELD_GET(HBG_REG_AN_NEG_STATE_NP_LINK_OK_B,
+					   link_status),
+				 HBG_MAC_LINK_WAIT_INTERVAL_US,
+				 HBG_MAC_LINK_WAIT_TIMEOUT_US);
+	if (ret)
 		hbg_np_link_fail_task_schedule(priv);
 }
 

drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.h

@@ -29,7 +29,12 @@ static inline bool hbg_fifo_is_full(struct hbg_priv *priv, enum hbg_dir dir)
 
 static inline u32 hbg_get_queue_used_num(struct hbg_ring *ring)
 {
-	return (ring->ntu + ring->len - ring->ntc) % ring->len;
+	u32 len = READ_ONCE(ring->len);
+
+	if (!len)
+		return 0;
+
+	return (READ_ONCE(ring->ntu) + len - READ_ONCE(ring->ntc)) % len;
 }
 
 netdev_tx_t hbg_net_start_xmit(struct sk_buff *skb, struct net_device *netdev);