From 1f5c23e2c10d642a23aa3ebb449670a5184b6aab Mon Sep 17 00:00:00 2001 From: Arthur Kepner Date: Mon, 16 Oct 2006 20:22:35 -0700 Subject: IB/mthca: Use mmiowb after doorbell ring We discovered a problem when running IPoIB applications on multiple CPUs on an Altix system. Many messages such as: ib_mthca 0002:01:00.0: SQ 000014 full (19941644 head, 19941707 tail, 64 max, 0 nreq) appear in syslog, and the driver wedges up. Apparently this is because writes to the doorbells from different CPUs reach the device out of order. The following patch adds mmiowb() calls after doorbell rings to ensure the doorbell writes are ordered. Signed-off-by: Arthur Kepner Signed-off-by: Roland Dreier --- drivers/infiniband/hw/mthca/mthca_qp.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers/infiniband/hw/mthca/mthca_qp.c') diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c index 5e5c58b9920..6a7822e0fc1 100644 --- a/drivers/infiniband/hw/mthca/mthca_qp.c +++ b/drivers/infiniband/hw/mthca/mthca_qp.c @@ -39,6 +39,8 @@ #include #include +#include + #include #include #include @@ -1732,6 +1734,11 @@ out: mthca_write64(doorbell, dev->kar + MTHCA_SEND_DOORBELL, MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock)); + /* + * Make sure doorbells don't leak out of SQ spinlock + * and reach the HCA out of order: + */ + mmiowb(); } qp->sq.next_ind = ind; @@ -1851,6 +1858,12 @@ out: qp->rq.next_ind = ind; qp->rq.head += nreq; + /* + * Make sure doorbells don't leak out of RQ spinlock and reach + * the HCA out of order: + */ + mmiowb(); + spin_unlock_irqrestore(&qp->rq.lock, flags); return err; } @@ -2112,6 +2125,12 @@ out: MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock)); } + /* + * Make sure doorbells don't leak out of SQ spinlock and reach + * the HCA out of order: + */ + mmiowb(); + spin_unlock_irqrestore(&qp->sq.lock, flags); return err; } -- cgit v1.2.3