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IB/{qib, hfi1}: Avoid flow control testing for RDMA write operation

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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@vger.kernel.org>
Reviewed-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Mike Marciniszyn 2017-08-21 18:26:20 -07:00 committed by Doug Ledford
parent 3aaee8ab47
commit 5b0ef650bd
2 changed files with 4 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/infiniband/hw/hfi1/rc.c
View File

@ -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);

4
drivers/infiniband/hw/qib/qib_rc.c
View File

@ -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 =