[PATCH] net/mlx4: Fix EEH recovery failure

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

The patch fixes couple of EEH recovery failures on PPC PowerNV
platform:

   * Release reserved memory regions in mlx4_pci_err_detected().
     Otherwise, __mlx4_init_one() fails because of reserving
     same memory regions recursively.
   * Disable PCI device in mlx4_pci_err_detected(). Otherwise,
     pci_enable_device() in __mlx4_init_one() doesn't enable
     the PCI device because it's already in enabled state indicated
     by struct pci_dev::enable_cnt.
   * Don't clear struct mlx4_priv instance in mlx4_pci_err_detected().
     Otherwise, __mlx4_init_one() runs into kernel crash because
     of dereferencing to NULL pointer.

With the patch applied, EEH recovery for mlx4 adapter succeeds on PPC
PowerNV platform.

   # lspci
   0003:0f:00.0 Network controller: Mellanox Technologies \
   MT27500 Family [ConnectX-3]

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 drivers/net/ethernet/mellanox/mlx4/main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 90de6e1..e118ac9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -2809,7 +2809,6 @@ static void mlx4_unload_one(struct pci_dev *pdev)
 	kfree(dev->caps.qp1_proxy);
 	kfree(dev->dev_vfs);
 
-	memset(priv, 0, sizeof(*priv));
 	priv->pci_dev_data = pci_dev_data;
 	priv->removed = 1;
 }
@@ -2900,6 +2899,8 @@ static pci_ers_result_t mlx4_pci_err_detected(struct pci_dev *pdev,
 					      pci_channel_state_t state)
 {
 	mlx4_unload_one(pdev);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
 
 	return state == pci_channel_io_perm_failure ?
 		PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_NEED_RESET;
-- 
1.8.3.2