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 */
67 DAT_RETURN
dapl_cno_wait(IN DAT_CNO_HANDLE cno_handle,IN DAT_TIMEOUT timeout,OUT DAT_EVD_HANDLE * evd_handle)68 dapl_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);
177 bail:
178 return (dat_status);
179 }
180