netdev - [net-next 2/8] net/mlx5: Read num

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Date:   Tue, 12 Nov 2019 17:13:42 +0000
From:   Saeed Mahameed <saeedm@...lanox.com>
To:     "David S. Miller" <davem@...emloft.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Parav Pandit <parav@...lanox.com>,
        Daniel Jurgens <danielj@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>
Subject: [net-next 2/8] net/mlx5: Read num_vfs before disabling SR-IOV

From: Parav Pandit <parav@...lanox.com>

mlx5_device_disable_sriov() currently reads num_vfs from the PCI core.
However when mlx5_device_disable_sriov() is executed, SR-IOV is
already disabled at the PCI level.
Due to this disable_hca() cleanup is not done during SR-IOV disable
flow.

mlx5_sriov_disable()
  pci_enable_sriov()
  mlx5_device_disable_sriov() <- num_vfs is zero here.

When SR-IOV enablement fails during mlx5_sriov_enable(), HCA's are left
in enabled stage because mlx5_device_disable_sriov() relies on num_vfs
from PCI core.

mlx5_sriov_enable()
  mlx5_device_enable_sriov()
  pci_enable_sriov() <- Fails

Hence, to overcome above issues,
(a) Read num_vfs before disabling SR-IOV and use it.
(b) Use num_vfs given when enabling sriov in error unwinding path.

Fixes: d886aba677a0 ("net/mlx5: Reduce dependency on enabled_vfs counter and num_vfs")
Signed-off-by: Parav Pandit <parav@...lanox.com>
Reviewed-by: Daniel Jurgens <danielj@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/sriov.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/sriov.c b/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
index f641f1336402..03f037811f1d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
@@ -108,10 +108,10 @@ static int mlx5_device_enable_sriov(struct mlx5_core_dev *dev, int num_vfs)
 	return 0;
 }
 
-static void mlx5_device_disable_sriov(struct mlx5_core_dev *dev, bool clear_vf)
+static void
+mlx5_device_disable_sriov(struct mlx5_core_dev *dev, int num_vfs, bool clear_vf)
 {
 	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
-	int num_vfs = pci_num_vf(dev->pdev);
 	int err;
 	int vf;
 
@@ -147,7 +147,7 @@ static int mlx5_sriov_enable(struct pci_dev *pdev, int num_vfs)
 	err = pci_enable_sriov(pdev, num_vfs);
 	if (err) {
 		mlx5_core_warn(dev, "pci_enable_sriov failed : %d\n", err);
-		mlx5_device_disable_sriov(dev, true);
+		mlx5_device_disable_sriov(dev, num_vfs, true);
 	}
 	return err;
 }
@@ -155,9 +155,10 @@ static int mlx5_sriov_enable(struct pci_dev *pdev, int num_vfs)
 static void mlx5_sriov_disable(struct pci_dev *pdev)
 {
 	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
+	int num_vfs = pci_num_vf(dev->pdev);
 
 	pci_disable_sriov(pdev);
-	mlx5_device_disable_sriov(dev, true);
+	mlx5_device_disable_sriov(dev, num_vfs, true);
 }
 
 int mlx5_core_sriov_configure(struct pci_dev *pdev, int num_vfs)
@@ -192,7 +193,7 @@ void mlx5_sriov_detach(struct mlx5_core_dev *dev)
 	if (!mlx5_core_is_pf(dev))
 		return;
 
-	mlx5_device_disable_sriov(dev, false);
+	mlx5_device_disable_sriov(dev, pci_num_vf(dev->pdev), false);
 }
 
 static u16 mlx5_get_max_vfs(struct mlx5_core_dev *dev)
-- 
2.21.0