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/openbmc/linux/drivers/infiniband/hw/qib/
H A Dqib_rc.c5b0ef650 Mon Aug 21 20:26:20 CDT 2017 Mike Marciniszyn <mike.marciniszyn@intel.com> IB/{qib, hfi1}: Avoid flow control testing for RDMA write operation

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>
5b0ef650 Mon Aug 21 20:26:20 CDT 2017 Mike Marciniszyn <mike.marciniszyn@intel.com> IB/{qib, hfi1}: Avoid flow control testing for RDMA write operation

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>
/openbmc/linux/drivers/infiniband/hw/hfi1/
H A Drc.c5b0ef650 Mon Aug 21 20:26:20 CDT 2017 Mike Marciniszyn <mike.marciniszyn@intel.com> IB/{qib, hfi1}: Avoid flow control testing for RDMA write operation

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>
5b0ef650 Mon Aug 21 20:26:20 CDT 2017 Mike Marciniszyn <mike.marciniszyn@intel.com> IB/{qib, hfi1}: Avoid flow control testing for RDMA write operation

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>