From ab28b171eabc0a414e0404844453c11af3caed10 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 24 May 2006 18:27:07 +0300 Subject: IB/mthca: Fix posting lists of 256 receive requests to SRQ for Tavor If we post a list of length exactly a multiple of 256, nreq in doorbell gets set to 256 which is wrong: it should be encoded by 0. This is because we only zero it out on the next WR, which may not be there. The solution is to ring the doorbell after posting a WQE, not before posting the next one. This is the same bug that we just fixed for QPs with non-shared RQ. Signed-off-by: Michael S. Tsirkin Signed-off-by: Roland Dreier --- drivers/infiniband/hw/mthca/mthca_srq.c | 41 +++++++++++++++++---------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/drivers/infiniband/hw/mthca/mthca_srq.c b/drivers/infiniband/hw/mthca/mthca_srq.c index 1ea433291fa..b292fefa3b4 100644 --- a/drivers/infiniband/hw/mthca/mthca_srq.c +++ b/drivers/infiniband/hw/mthca/mthca_srq.c @@ -490,26 +490,7 @@ int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr, first_ind = srq->first_free; - for (nreq = 0; wr; ++nreq, wr = wr->next) { - if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) { - nreq = 0; - - doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift); - doorbell[1] = cpu_to_be32(srq->srqn << 8); - - /* - * Make sure that descriptors are written - * before doorbell is rung. - */ - wmb(); - - mthca_write64(doorbell, - dev->kar + MTHCA_RECEIVE_DOORBELL, - MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock)); - - first_ind = srq->first_free; - } - + for (nreq = 0; wr; wr = wr->next) { ind = srq->first_free; if (ind < 0) { @@ -569,6 +550,26 @@ int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr, srq->wrid[ind] = wr->wr_id; srq->first_free = next_ind; + + ++nreq; + if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) { + nreq = 0; + + doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift); + doorbell[1] = cpu_to_be32(srq->srqn << 8); + + /* + * Make sure that descriptors are written + * before doorbell is rung. + */ + wmb(); + + mthca_write64(doorbell, + dev->kar + MTHCA_RECEIVE_DOORBELL, + MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock)); + + first_ind = srq->first_free; + } } if (likely(nreq)) { -- cgit v1.2.3