IPoIB: Don't start send-only joins while multicast thread is stopped

Fix the following race scenario:
  - Device is up.
  - Port event or set mcast list triggers ipoib_mcast_stop_thread,
    this cancels the query and waits on mcast "done" completion.
  - Completion is called and "done" is set.
  - Meanwhile, ipoib_mcast_send arrives and starts a new query,
    re-initializing "done".

Fix this by adding a "multicast started" bit and checking it before
starting a send-only join.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index e0a5412b7e68..2f85a9a831b1 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -78,6 +78,7 @@ enum {
         IPOIB_FLAG_SUBINTERFACE   = 4,
         IPOIB_MCAST_RUN           = 5,
         IPOIB_STOP_REAPER         = 6,
+        IPOIB_MCAST_STARTED       = 7,
 
         IPOIB_MAX_BACKOFF_SECONDS = 16,