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IB/qib: Prevent double completions after a timeout or RNR error

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There is a double completion associated with error handling for RC QPs.

The sequence is:

 - The do_rc_ack() routine fields an RNR nack and there are 0
   rnr_retries configured on the QP.
 - qib_error_qp() stops the pending timer
 - qib_rc_send_complete() is called from sdma_complete()
 - qib_rc_send_complete() starts the timer because the msb of the psn
   just completed says an ack is needed.
 - a bunch of flushes occur as ipoib posts WQEs to an error'ed QP
 - rc_timeout() calls qib_restart_rc()
 - qib_restart_rc() calls qib_send_complete() with a
   IB_WC_RETRY_EXC_ERR on a wqe that has already been completed in the
   past

The fix avoids starting the timer since another packet will never
arrive.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Mike Marciniszyn 2011-02-16 15:48:25 +00:00 committed by Roland Dreier
parent 414ed90cee
commit c0af2c057d
1 changed files with 2 additions and 1 deletions
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3
drivers/infiniband/hw/qib/qib_rc.c
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@ -1005,7 +1005,8 @@ void qib_rc_send_complete(struct qib_qp *qp, struct qib_ib_header *hdr)
* there are still requests that haven't been acked.
*/
if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
!(qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR | QIB_S_WAIT_PSN)))
!(qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR | QIB_S_WAIT_PSN)) &&
(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK))
start_timer(qp);
while (qp->s_last != qp->s_acked) {