/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2002-2003, Network Appliance, Inc. All rights reserved.
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 *
 * MODULE: dapl_evd_dto_callback.c
 *
 * PURPOSE: implements DTO callbacks from verbs
 *
 * $Id: dapl_evd_dto_callb.c,v 1.17 2003/07/30 18:13:38 hobie16 Exp $
 */

#include "dapl.h"
#include "dapl_evd_util.h"
#include "dapl_cno_util.h"
#include "dapl_cookie.h"
#include "dapl_adapter_util.h"

/*
 * dapl_evd_dto_callback
 *
 * Input:
 *      hca_handle_in,
 *      cq_handle_in,
 *      user_context_cq_p
 *
 * Output:
 *      none
 *
 * This is invoked for both DTO and MW bind completions. Strictly
 * speaking it is an event callback rather than just a DTO callback.
 *
 */

void
dapl_evd_dto_callback(
    IN ib_hca_handle_t  hca_handle,
    IN ib_cq_handle_t   cq_handle,
    IN void             *user_context)
{
        DAPL_EVD        *evd_ptr;
        DAT_RETURN      dat_status;
        DAPL_EVD_STATE  state;

        dapl_dbg_log(DAPL_DBG_TYPE_CALLBACK,
            "dapl_evd_dto_callback(%p, %p, %p)\n",
            hca_handle,
            cq_handle,
            user_context);

        evd_ptr = (DAPL_EVD *) user_context;

        dapl_os_assert(hca_handle ==
            evd_ptr->header.owner_ia->hca_ptr->ib_hca_handle);
        dapl_os_assert(evd_ptr->ib_cq_handle == cq_handle);
        dapl_os_assert(evd_ptr->header.magic == DAPL_MAGIC_EVD);

        /* Read once.  */
        state = *(volatile DAPL_EVD_STATE *) &evd_ptr->evd_state;

        dapl_dbg_log(DAPL_DBG_TYPE_EVD,
            "-- dapl_evd_dto_callback: CQ %p, state %x\n",
            (void *)evd_ptr->ib_cq_handle,
            state);

        /*
         * This function does not dequeue from the CQ; only the consumer
         * can do that. Instead, it wakes up waiters if any exist.
         * It rearms the completion only if completions should always occur
         * (specifically if a CNO is associated with the EVD and the
         * EVD is enabled.
         */

        if (state == DAPL_EVD_STATE_WAITED) {
                /*
                 * If we could, it would be best to avoid this wakeup
                 * (and the context switch) unless the number of events/CQs
                 * waiting for the waiter was its threshold.  We don't
                 * currently have the ability to determine that without
                 * dequeueing the events, and we can't do that for
                 * synchronization reasons (racing with the waiter waking
                 * up and dequeuing, sparked by other callbacks).
                 */

                /*
                 * We don't need to worry about taking the lock for the
                 * wakeup because wakeups are sticky.
                 */
                (void) dapl_os_wait_object_wakeup(&evd_ptr->wait_object);
        } else if (state == DAPL_EVD_STATE_OPEN) {
                DAPL_CNO *cno = evd_ptr->cno_ptr;
                if (evd_ptr->evd_enabled && (evd_ptr->cno_ptr != NULL)) {
                        /*
                         * Re-enable callback, *then* trigger.
                         * This guarantees we won't miss any events.
                         */
                        dat_status = DAPL_NOTIFY(evd_ptr)(
                            evd_ptr->ib_cq_handle, IB_NOTIFY_ON_NEXT_COMP, 0);

                        if (DAT_SUCCESS != dat_status) {
                                (void) dapls_evd_post_async_error_event(
                                    evd_ptr->header.owner_ia->async_error_evd,
                                    DAT_ASYNC_ERROR_PROVIDER_INTERNAL_ERROR,
                                    (DAT_IA_HANDLE)evd_ptr->header.owner_ia);
                        }

                        dapl_cno_trigger(cno, evd_ptr);
                }
        }
        dapl_dbg_log(DAPL_DBG_TYPE_RTN, "dapl_evd_dto_callback() returns\n");
}

/*
 * Local variables:
 *  c-indent-level: 4
 *  c-basic-offset: 4
 *  tab-width: 8
 * End:
 */