Re: [net-next 5/7] ixgbe: Check register reads for adapter removal

From: Mark Rustad <redacted>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
index 5e157ac..480c5c1 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h

@@ -124,6 +124,11 @@ s32 ixgbe_reset_pipeline_82599(struct ixgbe_hw *hw);

s32 ixgbe_get_thermal_sensor_data_generic(struct ixgbe_hw *hw);
s32 ixgbe_init_thermal_sensor_thresh_generic(struct ixgbe_hw *hw);

+#define IXGBE_FAILED_READ_REG 0xffffffffU
+
+void ixgbe_check_remove(struct ixgbe_hw *hw, u32 reg);
+#define IXGBE_REMOVED(a) unlikely(!(a))

+
static inline void IXGBE_WRITE_REG(struct ixgbe_hw *hw, u32 reg, u32 value)
{
	writel(value, hw->hw_addr + reg);

@@ -144,7 +149,15 @@ static inline void IXGBE_WRITE_REG64(struct ixgbe_hw *hw, u32 reg, u64 value)

static inline u32 IXGBE_READ_REG(struct ixgbe_hw *hw, u32 reg)
{
-	return readl(hw->hw_addr + reg);
+	u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
+	u32 value;
+
+	if (IXGBE_REMOVED(reg_addr))
+		return IXGBE_FAILED_READ_REG;
+	value = readl(reg_addr + reg);
+	if (unlikely(value == IXGBE_FAILED_READ_REG))
+		ixgbe_check_remove(hw, reg);
+	return value;
}

#define IXGBE_WRITE_REG_ARRAY(a, reg, offset, value) \

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 4d71277..896a8b0 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -283,6 +283,35 @@ static void ixgbe_service_event_schedule(struct ixgbe_adapter *adapter)

		schedule_work(&adapter->service_task);
}

+static void ixgbe_remove_adapter(struct ixgbe_hw *hw)
+{
+	struct ixgbe_adapter *adapter = hw->back;
+
+	if (!hw->hw_addr)
+		return;
+	hw->hw_addr = NULL;
+	e_dev_err("Adapter removed\n");
+}
+
+void ixgbe_check_remove(struct ixgbe_hw *hw, u32 reg)
+{
+	u32 value;
+
+	/* The following check not only optimizes a bit by not
+	 * performing a read on the status register when the
+	 * register just read was a status register read that
+	 * returned IXGBE_FAILED_READ_REG. It also blocks any
+	 * potential recursion.
+	 */
+	if (reg == IXGBE_STATUS) {
+		ixgbe_remove_adapter(hw);
+		return;
+	}
+	value = IXGBE_READ_REG(hw, IXGBE_STATUS);
+	if (value == IXGBE_FAILED_READ_REG)
+		ixgbe_remove_adapter(hw);
+}
+
static void ixgbe_service_event_complete(struct ixgbe_adapter *adapter)
{
	BUG_ON(!test_bit(__IXGBE_SERVICE_SCHED, &adapter->state));

@@ -2970,7 +2999,7 @@ void ixgbe_configure_tx_ring(struct ixgbe_adapter *adapter,

			ring->count * sizeof(union ixgbe_adv_tx_desc));
	IXGBE_WRITE_REG(hw, IXGBE_TDH(reg_idx), 0);
	IXGBE_WRITE_REG(hw, IXGBE_TDT(reg_idx), 0);
-	ring->tail = hw->hw_addr + IXGBE_TDT(reg_idx);
+	ring->tail = adapter->io_addr + IXGBE_TDT(reg_idx);

	/*
	 * set WTHRESH to encourage burst writeback, it should not be set

@@ -3373,7 +3402,7 @@ void ixgbe_configure_rx_ring(struct ixgbe_adapter *adapter,

			ring->count * sizeof(union ixgbe_adv_rx_desc));
	IXGBE_WRITE_REG(hw, IXGBE_RDH(reg_idx), 0);
	IXGBE_WRITE_REG(hw, IXGBE_RDT(reg_idx), 0);
-	ring->tail = hw->hw_addr + IXGBE_RDT(reg_idx);
+	ring->tail = adapter->io_addr + IXGBE_RDT(reg_idx);

	ixgbe_configure_srrctl(adapter, ring);
	ixgbe_configure_rscctl(adapter, ring);

@@ -7887,6 +7916,7 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

	hw->hw_addr = ioremap(pci_resource_start(pdev, 0),
			      pci_resource_len(pdev, 0));
+	adapter->io_addr = hw->hw_addr;
	if (!hw->hw_addr) {
		err = -EIO;
		goto err_ioremap;

@@ -8195,7 +8225,7 @@ err_register:

err_sw_init:
	ixgbe_disable_sriov(adapter);
	adapter->flags2 &= ~IXGBE_FLAG2_SEARCH_FOR_SFP;
-	iounmap(hw->hw_addr);
+	iounmap(adapter->io_addr);
err_ioremap:
	free_netdev(netdev);
err_alloc_etherdev:

@@ -8262,7 +8292,7 @@ static void ixgbe_remove(struct pci_dev *pdev)

	kfree(adapter->ixgbe_ieee_ets);

#endif
-	iounmap(adapter->hw.hw_addr);
+	iounmap(adapter->io_addr);
	pci_release_selected_regions(pdev, pci_select_bars(pdev,
				     IORESOURCE_MEM));

-- 
1.8.5.GIT

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