IPoIB: Fix race in detaching from mcast group before attaching
There's a race between ipoib_mcast_leave() and ipoib_mcast_join_finish()
where we can try to detach from a multicast group before we've
attached to it. Fix this by reordering the code in ipoib_mcast_leave
to free the multicast group first, which waits for the multicast
callback thread (which calls ipoib_mcast_join_finish()) to complete
before detaching from the group.
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 56c87a8..54fbead 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -644,6 +644,9 @@
struct ipoib_dev_priv *priv = netdev_priv(dev);
int ret = 0;
+ if (test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
+ ib_sa_free_multicast(mcast->mc);
+
if (test_and_clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
ipoib_dbg_mcast(priv, "leaving MGID " IPOIB_GID_FMT "\n",
IPOIB_GID_ARG(mcast->mcmember.mgid));
@@ -655,9 +658,6 @@
ipoib_warn(priv, "ipoib_mcast_detach failed (result = %d)\n", ret);
}
- if (test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
- ib_sa_free_multicast(mcast->mc);
-
return 0;
}