IB/ehca: Wait for async events to finish before destroying QP

This is necessary because, in a multicore environment, a race between
uverbs async handler and destroy QP could occur.

Signed-off-by: Stefan Roscher <stefan.roscher at de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_irq.c b/drivers/infiniband/hw/ehca/ehca_irq.c
index ca5eb0cb628c..ce1ab0571be3 100644
--- a/drivers/infiniband/hw/ehca/ehca_irq.c
+++ b/drivers/infiniband/hw/ehca/ehca_irq.c
@@ -204,6 +204,8 @@ static void qp_event_callback(struct ehca_shca *shca, u64 eqe,
 
         read_lock(&ehca_qp_idr_lock);
         qp = idr_find(&ehca_qp_idr, token);
+        if (qp)
+                atomic_inc(&qp->nr_events);
         read_unlock(&ehca_qp_idr_lock);
 
         if (!qp)
@@ -223,6 +225,8 @@ static void qp_event_callback(struct ehca_shca *shca, u64 eqe,
         if (fatal && qp->ext_type == EQPT_SRQBASE)
                 dispatch_qp_event(shca, qp, IB_EVENT_QP_LAST_WQE_REACHED);
 
+        if (atomic_dec_and_test(&qp->nr_events))
+                wake_up(&qp->wait_completion);
         return;
 }