netdev - [net-next 2/7] net/mlx5: Print more info on pci error handlers

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Date:   Mon,  1 Nov 2021 17:29:09 -0700
From:   Saeed Mahameed <saeed@...nel.org>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, Saeed Mahameed <saeedm@...dia.com>,
        Moshe Shemesh <moshe@...dia.com>
Subject: [net-next 2/7] net/mlx5: Print more info on pci error handlers

From: Saeed Mahameed <saeedm@...dia.com>

In case mlx5_pci_err_detected was called with state equals to
pci_channel_io_perm_failure, the driver will never come back up.

It is nice to know why the driver went to zombie land, so print some
useful information on pci err handlers.

Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
Reviewed-by: Moshe Shemesh <moshe@...dia.com>
---
 .../net/ethernet/mellanox/mlx5/core/main.c    | 51 ++++++++++++++-----
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index a92a92a52346..d9361546d5e4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -1604,12 +1604,28 @@ static void remove_one(struct pci_dev *pdev)
 	mlx5_devlink_free(devlink);
 }
 
+#define mlx5_pci_trace(dev, fmt, ...) ({ \
+	struct mlx5_core_dev *__dev = (dev); \
+	mlx5_core_info(__dev, "%s Device state = %d health sensors: %d pci_status: %d. " fmt, \
+		       __func__, __dev->state, mlx5_health_check_fatal_sensors(__dev), \
+		       __dev->pci_status, ##__VA_ARGS__); \
+})
+
+static const char *result2str(enum pci_ers_result result)
+{
+	return  result == PCI_ERS_RESULT_NEED_RESET ? "need reset" :
+		result == PCI_ERS_RESULT_DISCONNECT ? "disconnect" :
+		result == PCI_ERS_RESULT_RECOVERED  ? "recovered" :
+		"unknown";
+}
+
 static pci_ers_result_t mlx5_pci_err_detected(struct pci_dev *pdev,
 					      pci_channel_state_t state)
 {
 	struct mlx5_core_dev *dev = pci_get_drvdata(pdev);
+	enum pci_ers_result res;
 
-	mlx5_core_info(dev, "%s was called\n", __func__);
+	mlx5_pci_trace(dev, "Enter, pci channel state = %d\n", state);
 
 	mlx5_enter_error_state(dev, false);
 	mlx5_error_sw_reset(dev);
@@ -1617,8 +1633,11 @@ static pci_ers_result_t mlx5_pci_err_detected(struct pci_dev *pdev,
 	mlx5_drain_health_wq(dev);
 	mlx5_pci_disable_device(dev);
 
-	return state == pci_channel_io_perm_failure ?
+	res = state == pci_channel_io_perm_failure ?
 		PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_NEED_RESET;
+
+	mlx5_pci_trace(dev, "Exit, result = %d, %s\n",  res, result2str(res));
+	return res;
 }
 
 /* wait for the device to show vital signs by waiting
@@ -1652,28 +1671,34 @@ static int wait_vital(struct pci_dev *pdev)
 
 static pci_ers_result_t mlx5_pci_slot_reset(struct pci_dev *pdev)
 {
+	enum pci_ers_result res = PCI_ERS_RESULT_DISCONNECT;
 	struct mlx5_core_dev *dev = pci_get_drvdata(pdev);
 	int err;
 
-	mlx5_core_info(dev, "%s was called\n", __func__);
+	mlx5_pci_trace(dev, "Enter\n");
 
 	err = mlx5_pci_enable_device(dev);
 	if (err) {
 		mlx5_core_err(dev, "%s: mlx5_pci_enable_device failed with error code: %d\n",
 			      __func__, err);
-		return PCI_ERS_RESULT_DISCONNECT;
+		goto out;
 	}
 
 	pci_set_master(pdev);
 	pci_restore_state(pdev);
 	pci_save_state(pdev);
 
-	if (wait_vital(pdev)) {
-		mlx5_core_err(dev, "%s: wait_vital timed out\n", __func__);
-		return PCI_ERS_RESULT_DISCONNECT;
+	err = wait_vital(pdev);
+	if (err) {
+		mlx5_core_err(dev, "%s: wait vital failed with error code: %d\n",
+			      __func__, err);
+		goto out;
 	}
 
-	return PCI_ERS_RESULT_RECOVERED;
+	res = PCI_ERS_RESULT_RECOVERED;
+out:
+	mlx5_pci_trace(dev, "Exit, err = %d, result = %d, %s\n", err, res, result2str(res));
+	return res;
 }
 
 static void mlx5_pci_resume(struct pci_dev *pdev)
@@ -1681,14 +1706,12 @@ static void mlx5_pci_resume(struct pci_dev *pdev)
 	struct mlx5_core_dev *dev = pci_get_drvdata(pdev);
 	int err;
 
-	mlx5_core_info(dev, "%s was called\n", __func__);
+	mlx5_pci_trace(dev, "Enter, loading driver..\n");
 
 	err = mlx5_load_one(dev);
-	if (err)
-		mlx5_core_err(dev, "%s: mlx5_load_one failed with error code: %d\n",
-			      __func__, err);
-	else
-		mlx5_core_info(dev, "%s: device recovered\n", __func__);
+
+	mlx5_pci_trace(dev, "Done, err = %d, device %s\n", err,
+		       !err ? "recovered" : "Failed");
 }
 
 static const struct pci_error_handlers mlx5_err_handler = {
-- 
2.31.1