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>