dapl_cno_wait.c revision 9517:b4839b0aa7a4 
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright (c) 2002-2003, Network Appliance, Inc. All rights reserved.
24 */
25
26/*
27 * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
28 * Use is subject to license terms.
29 */
30
31/*
32 *
33 * MODULE: dapl_cno_wait.c
34 *
35 * PURPOSE: Wait for a consumer notification event
36 * Description: Interfaces in this file are completely described in
37 *		the DAPL 1.1 API, Chapter 6, section 3.2.3
38 *
39 * $Id: dapl_cno_wait.c,v 1.6 2003/06/16 17:53:32 sjs2 Exp $
40 */
41
42#include "dapl.h"
43#include "dapl_adapter_util.h"
44#include "dapl_ring_buffer_util.h"
45
46/*
47 * dapl_cno_wait
48 *
49 * DAPL Requirements Version xxx, 6.3.2.3
50 *
51 * Wait for a consumer notification event
52 *
53 * Input:
54 *	cno_handle
55 *	timeout
56 *	evd_handle
57 *
58 * Output:
59 *	evd_handle
60 *
61 * Returns:
62 *	DAT_SUCCESS
63 *	DAT_INVALID_HANDLE
64 *	DAT_QUEUE_EMPTY
65 *	DAT_INVALID_PARAMETER
66 */
67DAT_RETURN
68dapl_cno_wait(
69	IN	DAT_CNO_HANDLE		cno_handle,	/* cno_handle */
70	IN	DAT_TIMEOUT		timeout,	/* agent */
71	OUT	DAT_EVD_HANDLE		*evd_handle)	/* evd_handle */
72{
73	DAPL_CNO 	*cno_ptr;
74	DAPL_EVD	*evd_ptr, *head_evd_ptr;
75	DAT_RETURN 	dat_status;
76	int		nevents;
77
78	if (DAPL_BAD_HANDLE(cno_handle, DAPL_MAGIC_CNO)) {
79		dat_status = DAT_INVALID_HANDLE | DAT_INVALID_HANDLE_CNO;
80		goto bail;
81	}
82
83	dat_status = DAT_SUCCESS;
84	cno_ptr = (DAPL_CNO *) cno_handle;
85
86	if (cno_ptr->cno_state == DAPL_CNO_STATE_DEAD) {
87		dat_status = DAT_ERROR(DAT_INVALID_STATE,
88		    DAT_INVALID_STATE_CNO_DEAD);
89		goto bail;
90	}
91
92	dapl_os_lock(&cno_ptr->header.lock);
93	if (dapl_llist_is_empty(&cno_ptr->evd_list_head)) {
94		dapl_os_unlock(&cno_ptr->header.lock);
95		return (DAT_ERROR(DAT_QUEUE_EMPTY, 0));
96	}
97
98	/* scan evd list */
99	evd_ptr = (DAPL_EVD *)
100	    dapl_llist_next_entry(&cno_ptr->evd_list_head, NULL);
101
102	for (;;) {
103		/*
104		 * Check the evd ring buffer for events, if nothing is found
105		 * peek into the CQ to see if there are events
106		 */
107		if (dapls_rbuf_count(&evd_ptr->pending_event_queue) > 0) {
108			break;
109		}
110
111		nevents = 0;
112		dapls_ib_cq_peek(evd_ptr, &nevents);
113		if (nevents > 0) {
114			break;
115		}
116
117		evd_ptr = (DAPL_EVD *)
118		    dapl_llist_next_entry(&cno_ptr->evd_list_head,
119		    &evd_ptr->cno_list_entry);
120		if (evd_ptr == NULL) {
121			break;
122		}
123	}
124
125	/* shift list by one to simulate round-robin */
126	head_evd_ptr = (DAPL_EVD *)
127	    dapl_llist_remove_head(&cno_ptr->evd_list_head);
128	dapl_os_assert(head_evd_ptr != NULL);
129	dapl_llist_add_tail(&cno_ptr->evd_list_head,
130	    &head_evd_ptr->cno_list_entry, head_evd_ptr);
131
132	if (evd_ptr != NULL) {
133		*evd_handle = evd_ptr;
134		dapl_os_unlock(&cno_ptr->header.lock);
135		return (DAT_SUCCESS);
136	}
137
138	cno_ptr->cno_waiters++;
139	dapl_os_unlock(&cno_ptr->header.lock);
140
141	dat_status = dapls_ib_cno_wait(cno_ptr, timeout, &evd_ptr);
142
143	dapl_os_lock(&cno_ptr->header.lock);
144	cno_ptr->cno_waiters--;
145
146	/* verify that evd_ptr is still in the list */
147	head_evd_ptr = dapl_llist_next_entry(&cno_ptr->evd_list_head, NULL);
148	for (;;) {
149		if (head_evd_ptr == NULL || head_evd_ptr == evd_ptr) {
150			break;
151		}
152		head_evd_ptr = (DAPL_EVD *)
153		    dapl_llist_next_entry(&cno_ptr->evd_list_head,
154		    &head_evd_ptr->cno_list_entry);
155	}
156
157	if (cno_ptr->cno_state == DAPL_CNO_STATE_DEAD) {
158		dat_status = DAT_ERROR(DAT_INVALID_STATE,
159		    DAT_INVALID_STATE_CNO_DEAD);
160	} else if (dat_status == DAT_SUCCESS) {
161		/*
162		 * After the first triggering, this will be a valid handle.
163		 * If we're racing with wakeups of other CNO waiters,
164		 * that's ok.
165		 */
166		if (head_evd_ptr == evd_ptr && evd_ptr != NULL) {
167			*evd_handle = evd_ptr;
168		} else {
169			dat_status = DAT_ERROR(DAT_QUEUE_EMPTY, 0);
170		}
171	}
172	/*
173	 * The only other reason we could have made it out of
174	 * the loop is a timeout.
175	 */
176	dapl_os_unlock(&cno_ptr->header.lock);
177bail:
178	return (dat_status);
179}
180