From: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx> Section 9.7.7.2.5 of the 1.3 IBTA spec clearly says that receive credits should never apply to RDMA write. qib and hfi1 were doing that. The following situation will result in a QP hang: - A prior SEND or RDMA_WRITE with immmediate consumed the last credit for a QP using RC receive buffer credits - The prior op is acked so there are no more acks - The peer ULP fails to post receive for some reason - An RDMA write sees that the credits are exhausted and waits - The peer ULP posts receive buffers - The ULP posts a send or RDMA write that will be hung The fix is to avoid the credit test for the RDMA write operation. Cc: <stable@xxxxxxxxxxxxxxx> Reviewed-by: Kaike Wan <kaike.wan@xxxxxxxxx> Signed-off-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> --- drivers/infiniband/hw/hfi1/rc.c | 3 ++- drivers/infiniband/hw/qib/qib_rc.c | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c index 99defcc..e1cf0c0 100644 --- a/drivers/infiniband/hw/hfi1/rc.c +++ b/drivers/infiniband/hw/hfi1/rc.c @@ -442,7 +442,7 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) case IB_WR_RDMA_WRITE: if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) qp->s_lsn++; - /* FALLTHROUGH */ + goto no_flow_control; case IB_WR_RDMA_WRITE_WITH_IMM: /* If no credit, return. */ if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) && @@ -450,6 +450,7 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) qp->s_flags |= RVT_S_WAIT_SSN_CREDIT; goto bail; } +no_flow_control: put_ib_reth_vaddr( wqe->rdma_wr.remote_addr, &ohdr->u.rc.reth); diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c index 4ddbcac..e9a9173 100644 --- a/drivers/infiniband/hw/qib/qib_rc.c +++ b/drivers/infiniband/hw/qib/qib_rc.c @@ -348,7 +348,7 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags) case IB_WR_RDMA_WRITE: if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) qp->s_lsn++; - /* FALLTHROUGH */ + goto no_flow_control; case IB_WR_RDMA_WRITE_WITH_IMM: /* If no credit, return. */ if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT) && @@ -356,7 +356,7 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags) qp->s_flags |= RVT_S_WAIT_SSN_CREDIT; goto bail; } - +no_flow_control: ohdr->u.rc.reth.vaddr = cpu_to_be64(wqe->rdma_wr.remote_addr); ohdr->u.rc.reth.rkey =