RDMA/ipoib: drop skb on path record lookup failure

In unicast_arp_send function there is an inconsistency in error handling
of path_rec_start call. If path_rec_start is called because of an absent
ah field, skb will be dropped. But if it is called on a creation of a
new path, or if the path is invalid, skb will be added to the tail of
path queue.  In case of a new path it will be dropped on path_free, but
in case of invalid path it can stay in the queue forever.

This patch unifies the behavior, dropping skb in all cases
of path_rec_start failure.

Signed-off-by: Evgenii Smirnov <evgenii.smirnov@profitbricks.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 788bb95..2ce40a7 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -1054,62 +1054,42 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
 
        path = __path_find(dev, phdr->hwaddr + 4);
        if (!path || !path->ah || !path->ah->valid) {
-               int new_path = 0;
-
                if (!path) {
                        path = path_rec_create(dev, phdr->hwaddr + 4);
-                       new_path = 1;
+                       if (!path)
+                               goto drop_and_unlock;
+                       __path_add(dev, path);
+               } else {
+                       /*
+                        * make sure there are no changes in the existing
+                        * path record
+                        */
+                       init_path_rec(priv, path, phdr->hwaddr + 4);
+               }
+               if (!path->query && path_rec_start(dev, path)) {
+                       goto drop_and_unlock;
                }
-               if (path) {
-                       if (!new_path)
-                               /* make sure there is no changes in the existing path record */
-                               init_path_rec(priv, path, phdr->hwaddr + 4);
-
-                       if (skb_queue_len(&path->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
-                               push_pseudo_header(skb, phdr->hwaddr);
-                               __skb_queue_tail(&path->queue, skb);
-                       } else {
-                               ++dev->stats.tx_dropped;
-                               dev_kfree_skb_any(skb);
-                       }
 
-                       if (!path->query && path_rec_start(dev, path)) {
-                               spin_unlock_irqrestore(&priv->lock, flags);
-                               if (new_path)
-                                       path_free(dev, path);
-                               return;
-                       } else
-                               __path_add(dev, path);
+               if (skb_queue_len(&path->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
+                       push_pseudo_header(skb, phdr->hwaddr);
+                       __skb_queue_tail(&path->queue, skb);
+                       goto unlock;
                } else {
                        goto drop_and_unlock;
                }
-
-               spin_unlock_irqrestore(&priv->lock, flags);
-               return;
-       }
-
-       if (path->ah && path->ah->valid) {
-               ipoib_dbg(priv, "Send unicast ARP to %08x\n",
-                         be32_to_cpu(sa_path_get_dlid(&path->pathrec)));
-
-               spin_unlock_irqrestore(&priv->lock, flags);
-               path->ah->last_send = rn->send(dev, skb, path->ah->ah,
-                                              IPOIB_QPN(phdr->hwaddr));
-               return;
-       } else if ((path->query || !path_rec_start(dev, path)) &&
-                  skb_queue_len(&path->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
-               push_pseudo_header(skb, phdr->hwaddr);
-               __skb_queue_tail(&path->queue, skb);
-       } else {
-               goto drop_and_unlock;
        }
 
        spin_unlock_irqrestore(&priv->lock, flags);
+       ipoib_dbg(priv, "Send unicast ARP to %08x\n",
+                 be32_to_cpu(sa_path_get_dlid(&path->pathrec)));
+       path->ah->last_send = rn->send(dev, skb, path->ah->ah,
+                                      IPOIB_QPN(phdr->hwaddr));
        return;
 
 drop_and_unlock:
        ++dev->stats.tx_dropped;
        dev_kfree_skb_any(skb);
+unlock:
        spin_unlock_irqrestore(&priv->lock, flags);
 }