[PATCH 2/2 Xenial SRU] net/mlx4_core: Avoid repeated calls to pci enable/disable

[tim.gardner at canonical.com]

From: Daniel Jurgens <danielj at mellanox.com>

BugLink: http://bugs.launchpad.net/bugs/1574697

Maintain the PCI status and provide wrappers for enabling and disabling
the PCI device.  Performing the actions more than once without doing
its opposite results in warning logs.

This occurred when EEH hotplugged the device causing a warning for
disabling an already disabled device.

Fixes: 2ba5fbd62b25 ('net/mlx4_core: Handle AER flow properly')
Signed-off-by: Daniel Jurgens <danielj at mellanox.com>
Signed-off-by: Yishai Hadas <yishaih at mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(back ported from commit 4bfd2e6e53435a214888fd35e230157a38ffc6a0)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>

Conflicts:
	drivers/net/ethernet/mellanox/mlx4/main.c
---
 drivers/net/ethernet/mellanox/mlx4/main.c | 39 +++++++++++++++++++++++++++----
 include/linux/mlx4/device.h               |  7 ++++++
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index f07c4f3..b0cff8a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -3043,6 +3043,34 @@ static int mlx4_check_dev_cap(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap
 	return 0;
 }
 
+static int mlx4_pci_enable_device(struct mlx4_dev *dev)
+{
+	struct pci_dev *pdev = dev->persist->pdev;
+	int err = 0;
+
+	mutex_lock(&dev->persist->pci_status_mutex);
+	if (dev->persist->pci_status == MLX4_PCI_STATUS_DISABLED) {
+		err = pci_enable_device(pdev);
+		if (!err)
+			dev->persist->pci_status = MLX4_PCI_STATUS_ENABLED;
+	}
+	mutex_unlock(&dev->persist->pci_status_mutex);
+
+	return err;
+}
+
+static void mlx4_pci_disable_device(struct mlx4_dev *dev)
+{
+	struct pci_dev *pdev = dev->persist->pdev;
+
+	mutex_lock(&dev->persist->pci_status_mutex);
+	if (dev->persist->pci_status == MLX4_PCI_STATUS_ENABLED) {
+		pci_disable_device(pdev);
+		dev->persist->pci_status = MLX4_PCI_STATUS_DISABLED;
+	}
+	mutex_unlock(&dev->persist->pci_status_mutex);
+}
+
 static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 			 int total_vfs, int *nvfs, struct mlx4_priv *priv,
 			 int reset_flow)
@@ -3453,7 +3481,7 @@ static int __mlx4_init_one(struct pci_dev *pdev, int pci_dev_data,
 
 	pr_info(DRV_NAME ": Initializing %s\n", pci_name(pdev));
 
-	err = pci_enable_device(pdev);
+	err = mlx4_pci_enable_device(&priv->dev);
 	if (err) {
 		dev_err(&pdev->dev, "Cannot enable PCI device, aborting\n");
 		return err;
@@ -3586,7 +3614,7 @@ err_release_regions:
 	pci_release_regions(pdev);
 
 err_disable_pdev:
-	pci_disable_device(pdev);
+	mlx4_pci_disable_device(&priv->dev);
 	pci_set_drvdata(pdev, NULL);
 	return err;
 }
@@ -3615,6 +3643,7 @@ static int mlx4_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	priv->pci_dev_data = id->driver_data;
 	mutex_init(&dev->persist->device_state_mutex);
 	mutex_init(&dev->persist->interface_state_mutex);
+	mutex_init(&dev->persist->pci_status_mutex);
 
 	ret =  __mlx4_init_one(pdev, id->driver_data, priv);
 	if (ret) {
@@ -3753,7 +3782,7 @@ static void mlx4_remove_one(struct pci_dev *pdev)
 	}
 
 	pci_release_regions(pdev);
-	pci_disable_device(pdev);
+	mlx4_pci_disable_device(dev);
 	kfree(dev->persist);
 	kfree(priv);
 	pci_set_drvdata(pdev, NULL);
@@ -3871,7 +3900,7 @@ static pci_ers_result_t mlx4_pci_err_detected(struct pci_dev *pdev,
 	if (state == pci_channel_io_perm_failure)
 		return PCI_ERS_RESULT_DISCONNECT;
 
-	pci_disable_device(pdev);
+	mlx4_pci_disable_device(persist->dev);
 	return PCI_ERS_RESULT_NEED_RESET;
 }
 
@@ -3882,7 +3911,7 @@ static pci_ers_result_t mlx4_pci_slot_reset(struct pci_dev *pdev)
 	int err;
 
 	mlx4_err(dev, "mlx4_pci_slot_reset was called\n");
-	err = pci_enable_device(pdev);
+	err = mlx4_pci_enable_device(dev);
 	if (err) {
 		mlx4_err(dev, "Can not re-enable device, err=%d\n", err);
 		return PCI_ERS_RESULT_DISCONNECT;
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 8bab38f..a4fb7db 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -824,6 +824,11 @@ struct mlx4_vf_dev {
 	u8			n_ports;
 };
 
+enum mlx4_pci_status {
+	MLX4_PCI_STATUS_DISABLED,
+	MLX4_PCI_STATUS_ENABLED,
+};
+
 struct mlx4_dev_persistent {
 	struct pci_dev	       *pdev;
 	struct mlx4_dev	       *dev;
@@ -837,6 +842,8 @@ struct mlx4_dev_persistent {
 	u8		state;
 	struct mutex	interface_state_mutex; /* protect SW state */
 	u8	interface_state;
+	struct mutex		pci_status_mutex; /* sync pci state */
+	enum mlx4_pci_status	pci_status;
 };
 
 struct mlx4_dev {
-- 
1.9.1