IPoIB: Drop priv->lock before calling ipoib_send()
Roland Dreier [Sun, 6 Sep 2009 03:23:40 +0000 (20:23 -0700)]
IPoIB currently must use irqsave locking for priv->lock, since it is
taken from interrupt context in one path.  However, ipoib_send() does
skb_orphan(), and the network stack locking is not IRQ-safe.
Therefore we need to make sure we don't hold priv->lock when calling
ipoib_send() to avoid lockdep warnings (the code was almost certainly
safe in practice, since the only code path that takes priv->lock from
interrupt context would never call into the network stack).

Addresses: http://bugzilla.kernel.org/show_bug.cgi?id=13757
Reported-by: Bart Van Assche <bart.vanassche@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/ipoib/ipoib_main.c
drivers/infiniband/ulp/ipoib/ipoib_multicast.c

index e319d91..2bf5116 100644 (file)
@@ -604,8 +604,11 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
                                           skb_queue_len(&neigh->queue));
                                goto err_drop;
                        }
-               } else
+               } else {
+                       spin_unlock_irqrestore(&priv->lock, flags);
                        ipoib_send(dev, skb, path->ah, IPOIB_QPN(skb_dst(skb)->neighbour->ha));
+                       return;
+               }
        } else {
                neigh->ah  = NULL;
 
@@ -688,7 +691,9 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
                ipoib_dbg(priv, "Send unicast ARP to %04x\n",
                          be16_to_cpu(path->pathrec.dlid));
 
+               spin_unlock_irqrestore(&priv->lock, flags);
                ipoib_send(dev, skb, path->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) {
                /* put pseudoheader back on for next time */
index a0e9753..a0825fe 100644 (file)
@@ -720,7 +720,9 @@ out:
                        }
                }
 
+               spin_unlock_irqrestore(&priv->lock, flags);
                ipoib_send(dev, skb, mcast->ah, IB_MULTICAST_QPN);
+               return;
        }
 
 unlock: