NAME

       ibv_query_qp_data_in_order - check if qp data is guaranteed to be in order.

SYNOPSIS

              #include <infiniband/verbs.h>

              int ibv_query_qp_data_in_order(struct ibv_qp *qp, enum ibv_wr_opcode op, uint32_t flags);

DESCRIPTION

       ibv_query_qp_data_in_order()  Checks  whether  WQE  data  is  guaranteed to be written in-order, and thus
       reader may poll for data instead of poll  for  completion.   This  function  indicates  data  is  written
       in-order  within each WQE, but cannot be used to determine ordering between separate WQEs.  This function
       describes ordering at the receiving side of the QP, not the sending side.

ARGUMENTS

       qp

              The local queue pair (QP) to query.

       op

              The operation type to query about. Different operation types may write data in a different order.
              For RDMA read operations: describes ordering of RDMA reads posted on  this  local  QP.   For  RDMA
              write  operations:  describes  ordering  of remote RDMA writes being done into this local QP.  For
              RDMA send operations: describes ordering of remote RDMA sends being done into this local QP.  This
              function should not be used to determine ordering of other operation types.

       flags  Flags are used to select a query type.  Supported values:

       IBV_QUERY_QP_DATA_IN_ORDER_RETURN_CAPS - Query for  supported  capabilities  and  return  a  capabilities
       vector.

       Passing   0   is   equivalent   to   using   IBV_QUERY_QP_DATA_IN_ORDER_RETURN_CAPS   and   checking  for
       IBV_QUERY_QP_DATA_IN_ORDER_WHOLE_MSG support.

RETURN VALUE

       ibv_query_qp_data_in_order() Return value is determined by flags.  For each capability bit, 1 is returned
       if the data is guaranteed to be written in-order for  selected  operation  and  type,  0  otherwise.   If
       IBV_QUERY_QP_DATA_IN_ORDER_RETURN_CAPS flag is used, return value can consist of following capabilities:

       IBV_QUERY_QP_DATA_IN_ORDER_WHOLE_MSG - All data is being written in order.

       IBV_QUERY_QP_DATA_IN_ORDER_ALIGNED_128_BYTES - Each 128 bytes aligned block is being written in order.

       If  flags  is  0,  the  function will return 1 if IBV_QUERY_QP_DATA_IN_ORDER_WHOLE_MSG is supported and 0
       otherwise.

NOTES

       Return value is valid only when the data is read by the CPU and relaxed ordering MR is not the target  of
       the transfer.

SEE ALSO

       ibv_query_qp(3)

AUTHOR

       Patrisious Haddad phaddad@nvidia.com

       Yochai Cohen yochai@nvidia.com

libibverbs                                          2020-3-3                       ibv_query_qp_data_in_order(3)