IB/mlx4: Fix possible missed completion event

If an erroneous CQE is polled in the first iteration (i.e. npolled ==
0), we don't update the consumer index and hence the hardware could
get a wrong notion of how many CQEs software polled.  Fix this by
unconditionally updating the doorbell record.  We could change the
check to be something like

	if (npolled || err != -EAGAIN)
		...

but it does not seem worth the effort since a posted write to memory
should not cost too much.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/mlx4/cq.c b/drivers/infiniband/hw/mlx4/cq.c
index 5ecf38d97269..275861bddf1c 100644
--- a/drivers/infiniband/hw/mlx4/cq.c
+++ b/drivers/infiniband/hw/mlx4/cq.c
@@ -747,8 +747,7 @@ int mlx4_ib_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
                         break;
         }
 
-        if (npolled)
-                mlx4_cq_set_ci(&cq->mcq);
+        mlx4_cq_set_ci(&cq->mcq);
 
         spin_unlock_irqrestore(&cq->lock, flags);