ibmveth: Fix checksum offload failure handling

Fix a number of issues in ibmveth_set_csum_offload:

- set_attr6 and clr_attr6 may be used uninitialised

- We store the result of the IPV4 checksum change in ret but overwrite
  it in a couple of places before checking it again later. Add ret4
  to make it obvious what we are doing.

- We weren't clearing the NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM flags
  if the enable of that hypervisor feature failed.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 11 deletions

diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index 07830f918aed..8dd5fccef725 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -757,7 +757,7 @@ static int ibmveth_set_csum_offload(struct net_device *dev, u32 data)
         struct ibmveth_adapter *adapter = netdev_priv(dev);
         unsigned long set_attr, clr_attr, ret_attr;
         unsigned long set_attr6, clr_attr6;
-        long ret, ret6;
+        long ret, ret4, ret6;
         int rc1 = 0, rc2 = 0;
         int restart = 0;
 
@@ -770,6 +770,8 @@ static int ibmveth_set_csum_offload(struct net_device *dev, u32 data)
 
         set_attr = 0;
         clr_attr = 0;
+        set_attr6 = 0;
+        clr_attr6 = 0;
 
         if (data) {
                 set_attr = IBMVETH_ILLAN_IPV4_TCP_CSUM;
@@ -784,16 +786,20 @@ static int ibmveth_set_csum_offload(struct net_device *dev, u32 data)
         if (ret == H_SUCCESS && !(ret_attr & IBMVETH_ILLAN_ACTIVE_TRUNK) &&
             !(ret_attr & IBMVETH_ILLAN_TRUNK_PRI_MASK) &&
             (ret_attr & IBMVETH_ILLAN_PADDED_PKT_CSUM)) {
-                ret = h_illan_attributes(adapter->vdev->unit_address, clr_attr,
+                ret4 = h_illan_attributes(adapter->vdev->unit_address, clr_attr,
                                          set_attr, &ret_attr);
 
-                if (ret != H_SUCCESS) {
+                if (ret4 != H_SUCCESS) {
                         netdev_err(dev, "unable to change IPv4 checksum "
                                         "offload settings. %d rc=%ld\n",
-                                        data, ret);
+                                        data, ret4);
+
+                        h_illan_attributes(adapter->vdev->unit_address,
+                                           set_attr, clr_attr, &ret_attr);
+
+                        if (data == 1)
+                                dev->features &= ~NETIF_F_IP_CSUM;
 
-                        ret = h_illan_attributes(adapter->vdev->unit_address,
-                                                 set_attr, clr_attr, &ret_attr);
                 } else {
                         adapter->fw_ipv4_csum_support = data;
                 }
@@ -804,15 +810,18 @@ static int ibmveth_set_csum_offload(struct net_device *dev, u32 data)
                 if (ret6 != H_SUCCESS) {
                         netdev_err(dev, "unable to change IPv6 checksum "
                                         "offload settings. %d rc=%ld\n",
-                                        data, ret);
+                                        data, ret6);
+
+                        h_illan_attributes(adapter->vdev->unit_address,
+                                           set_attr6, clr_attr6, &ret_attr);
+
+                        if (data == 1)
+                                dev->features &= ~NETIF_F_IPV6_CSUM;
 
-                        ret = h_illan_attributes(adapter->vdev->unit_address,
-                                                 set_attr6, clr_attr6,
-                                                 &ret_attr);
                 } else
                         adapter->fw_ipv6_csum_support = data;
 
-                if (ret == H_SUCCESS || ret6 == H_SUCCESS)
+                if (ret4 == H_SUCCESS || ret6 == H_SUCCESS)
                         adapter->rx_csum = data;
                 else
                         rc1 = -EIO;