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IB/mlx4: Fix possible missed completion event

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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>
This commit is contained in:
Eli Cohen 2012-03-06 15:50:51 +02:00 committed by Roland Dreier
parent 5984be9004
commit 3616f9cead
1 changed files with 1 additions and 2 deletions
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3
drivers/infiniband/hw/mlx4/cq.c
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@ -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);