/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpidi_ch3_impl.h"
/*#include "mpidpre.h"*/
#include "mpid_nem_impl.h"
#if defined (MPID_NEM_INLINE) && MPID_NEM_INLINE
#include "mpid_nem_inline.h"
#endif

/*
 * MPIDI_CH3_iStartMsgv() attempts to send the message immediately.
 * If the entire message is successfully sent, then NULL is returned.
 * Otherwise a request is allocated, the iovec and the first buffer
 * pointed to by the iovec (which is assumed to be a MPIDI_CH3_Pkt_t)
 * are copied into the request, and a pointer to the request is
 * returned.  An error condition also results in a request be
 * allocated and the errror being returned in the status field of the
 * request.
 */

/* NOTE - The completion action associated with a request created by CH3_iStartMsgv() is alway null (onDataAvail = 0).  This
   implies that CH3_iStartMsgv() can only be used when the entire message can be described by a single iovec of size
   MPID_IOV_LIMIT. */
    
#undef FUNCNAME
#define FUNCNAME MPIDI_CH3_iStartMsgv
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
int MPIDI_CH3_iStartMsgv (MPIDI_VC_t * vc, MPID_IOV * iov, int n_iov, MPID_Request ** sreq_ptr)
{
    MPID_Request * sreq = NULL;
    int mpi_errno = MPI_SUCCESS;
    int again = 0;
    int j;
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_CH3_ISTARTMSGV);

    MPIDI_FUNC_ENTER(MPID_STATE_MPIDI_CH3_ISTARTMSGV);

    MPIU_Assert (n_iov <= MPID_IOV_LIMIT);
    MPIU_Assert (iov[0].MPID_IOV_LEN <= sizeof(MPIDI_CH3_Pkt_t));

    /* The channel uses a fixed length header, the size of which is
     * the maximum of all possible packet headers */
    iov[0].MPID_IOV_LEN = sizeof(MPIDI_CH3_Pkt_t);
    MPIDI_DBG_Print_packet((MPIDI_CH3_Pkt_t*)iov[0].MPID_IOV_BUF);
    
    if (MPIDI_CH3I_SendQ_empty (CH3_NORMAL_QUEUE))
        /* MT */
    {
	MPID_IOV *remaining_iov = iov;
	int remaining_n_iov = n_iov;

        MPIU_DBG_MSG (CH3_CHANNEL, VERBOSE, "iStartMsgv");
        MPIU_DBG_STMT (CH3_CHANNEL, VERBOSE, {
            int total = 0;
            int i;
            for (i = 0; i < n_iov; ++i)
                total += iov[i].MPID_IOV_LEN;
                    
            MPIU_DBG_MSG_D (CH3_CHANNEL, VERBOSE, "   + len=%d ", total);
        });
	mpi_errno = MPID_nem_mpich2_sendv_header (&remaining_iov, &remaining_n_iov, vc, &again);
        if (mpi_errno) MPIU_ERR_POP (mpi_errno);
	while (!again && (remaining_n_iov > 0))
	{
            MPIU_DBG_STMT (CH3_CHANNEL, VERBOSE, {
                int total = 0;
                int i;
                for (i = 0; i < remaining_n_iov; ++i)
                    total += remaining_iov[i].MPID_IOV_LEN;
                MPIU_DBG_MSG_D (CH3_CHANNEL, VERBOSE, "   + len=%d ", total);
            });

	    mpi_errno = MPID_nem_mpich2_sendv (&remaining_iov, &remaining_n_iov, vc, &again);
            if (mpi_errno) MPIU_ERR_POP (mpi_errno);
	}
        MPIU_DBG_STMT (CH3_CHANNEL, VERBOSE, {
            int total = 0;
            int i;
            for (i = 0; i < remaining_n_iov; ++i)
                total += remaining_iov[i].MPID_IOV_LEN;
            MPIU_DBG_MSG_D (CH3_CHANNEL, VERBOSE, "   - len=%d ", total);
        });

	if (again)
	{
            /* Create a new request and save remaining portions of the
	     * iov in it. */
 	    sreq = MPID_Request_create();
	    MPIU_Assert(sreq != NULL);
	    MPIU_Object_set_ref(sreq, 2);
	    sreq->kind = MPID_REQUEST_SEND;
	    for (j = 0; j < remaining_n_iov; ++j)
	    {
		sreq->dev.iov[j] = remaining_iov[j];
	    }
	    sreq->ch.iov_offset = 0;
	    sreq->dev.iov_count = remaining_n_iov;
	    sreq->dev.OnDataAvail = 0;
	    sreq->ch.vc = vc;
	    if ( iov == remaining_iov )
	    {
		/* header was not sent, so iov[0] might point to something on the stack */
		sreq->ch.pkt = *(MPIDI_CH3_Pkt_t *) iov[0].MPID_IOV_BUF;
		sreq->dev.iov[0].MPID_IOV_BUF = (char *) &sreq->ch.pkt;
		sreq->dev.iov[0].MPID_IOV_LEN = iov[0].MPID_IOV_LEN;
	    }
	    MPIDI_CH3I_SendQ_enqueue (sreq, CH3_NORMAL_QUEUE);
	    MPIU_Assert (MPIDI_CH3I_active_send[CH3_NORMAL_QUEUE] == NULL);
	    MPIDI_CH3I_active_send[CH3_NORMAL_QUEUE] = sreq;
	}
    }
    else
    {
	int i;
	
	MPIDI_DBG_PRINTF((55, FCNAME, "request enqueued"));
	/* create a request */
	sreq = MPID_Request_create();
	MPIU_Assert(sreq != NULL);
	MPIU_Object_set_ref(sreq, 2);
	sreq->kind = MPID_REQUEST_SEND;

	sreq->ch.pkt = *(MPIDI_CH3_Pkt_t *) iov[0].MPID_IOV_BUF;
	sreq->dev.iov[0].MPID_IOV_BUF = (char *) &sreq->ch.pkt;
	sreq->dev.iov[0].MPID_IOV_LEN = iov[0].MPID_IOV_LEN;

	/* copy iov */
	for (i = 1; i < n_iov; ++i)
	{
	    sreq->dev.iov[i] = iov[i];
	}

	sreq->ch.iov_offset = 0;
	sreq->dev.iov_count = n_iov;
	sreq->dev.OnDataAvail = 0;
	sreq->ch.vc = vc;
	MPIDI_CH3I_SendQ_enqueue (sreq, CH3_NORMAL_QUEUE);
    }
    
    *sreq_ptr = sreq;
    
 fn_exit:
    MPIDI_FUNC_EXIT(MPID_STATE_MPIDI_CH3_ISTARTMSGV);
    return mpi_errno;
 fn_fail:
    goto fn_exit;
}

