ethtool: Fix filter addition when caching n-tuple filters

We can allow a filter to be added successfully to the underlying
hardware, but still return an error if the cached list memory
allocation fails.  This patch fixes that condition.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 16 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index a1280f643bf4..fbbe4b49116b 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -283,18 +283,17 @@ err_out:
         return ret;
 }
 
-static int __rx_ntuple_filter_add(struct ethtool_rx_ntuple_list *list,
-                                  struct ethtool_rx_ntuple_flow_spec *spec)
+static void __rx_ntuple_filter_add(struct ethtool_rx_ntuple_list *list,
+                              struct ethtool_rx_ntuple_flow_spec *spec,
+                              struct ethtool_rx_ntuple_flow_spec_container *fsc)
 {
-        struct ethtool_rx_ntuple_flow_spec_container *fsc;
 
         /* don't add filters forever */
-        if (list->count >= ETHTOOL_MAX_NTUPLE_LIST_ENTRY)
-                return 0;
-
-        fsc = kmalloc(sizeof(*fsc), GFP_ATOMIC);
-        if (!fsc)
-                return -ENOMEM;
+        if (list->count >= ETHTOOL_MAX_NTUPLE_LIST_ENTRY) {
+                /* free the container */
+                kfree(fsc);
+                return;
+        }
 
         /* Copy the whole filter over */
         fsc->fs.flow_type = spec->flow_type;
@@ -310,14 +309,13 @@ static int __rx_ntuple_filter_add(struct ethtool_rx_ntuple_list *list,
         /* add to the list */
         list_add_tail_rcu(&fsc->list, &list->list);
         list->count++;
-
-        return 0;
 }
 
 static int ethtool_set_rx_ntuple(struct net_device *dev, void __user *useraddr)
 {
         struct ethtool_rx_ntuple cmd;
         const struct ethtool_ops *ops = dev->ethtool_ops;
+        struct ethtool_rx_ntuple_flow_spec_container *fsc = NULL;
         int ret;
 
         if (!ops->set_rx_ntuple)
@@ -329,16 +327,26 @@ static int ethtool_set_rx_ntuple(struct net_device *dev, void __user *useraddr)
         if (copy_from_user(&cmd, useraddr, sizeof(cmd)))
                 return -EFAULT;
 
-        ret = ops->set_rx_ntuple(dev, &cmd);
-
         /*
          * Cache filter in dev struct for GET operation only if
          * the underlying driver doesn't have its own GET operation, and
-         * only if the filter was added successfully.
+         * only if the filter was added successfully.  First make sure we
+         * can allocate the filter, then continue if successful.
          */
-        if (!ops->get_rx_ntuple && !ret)
-                if (__rx_ntuple_filter_add(&dev->ethtool_ntuple_list, &cmd.fs))
+        if (!ops->get_rx_ntuple) {
+                fsc = kmalloc(sizeof(*fsc), GFP_ATOMIC);
+                if (!fsc)
                         return -ENOMEM;
+        }
+
+        ret = ops->set_rx_ntuple(dev, &cmd);
+        if (ret) {
+                kfree(fsc);
+                return ret;
+        }
+
+        if (!ops->get_rx_ntuple)
+                __rx_ntuple_filter_add(&dev->ethtool_ntuple_list, &cmd.fs, fsc);
 
         return ret;
 }