1*9e39c5baSBill Taylor /*
2*9e39c5baSBill Taylor * CDDL HEADER START
3*9e39c5baSBill Taylor *
4*9e39c5baSBill Taylor * The contents of this file are subject to the terms of the
5*9e39c5baSBill Taylor * Common Development and Distribution License (the "License").
6*9e39c5baSBill Taylor * You may not use this file except in compliance with the License.
7*9e39c5baSBill Taylor *
8*9e39c5baSBill Taylor * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*9e39c5baSBill Taylor * or http://www.opensolaris.org/os/licensing.
10*9e39c5baSBill Taylor * See the License for the specific language governing permissions
11*9e39c5baSBill Taylor * and limitations under the License.
12*9e39c5baSBill Taylor *
13*9e39c5baSBill Taylor * When distributing Covered Code, include this CDDL HEADER in each
14*9e39c5baSBill Taylor * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*9e39c5baSBill Taylor * If applicable, add the following below this CDDL HEADER, with the
16*9e39c5baSBill Taylor * fields enclosed by brackets "[]" replaced with your own identifying
17*9e39c5baSBill Taylor * information: Portions Copyright [yyyy] [name of copyright owner]
18*9e39c5baSBill Taylor *
19*9e39c5baSBill Taylor * CDDL HEADER END
20*9e39c5baSBill Taylor */
21*9e39c5baSBill Taylor
22*9e39c5baSBill Taylor /*
23*9e39c5baSBill Taylor * Copyright (c) 2002-2003, Network Appliance, Inc. All rights reserved.
24*9e39c5baSBill Taylor */
25*9e39c5baSBill Taylor
26*9e39c5baSBill Taylor /*
27*9e39c5baSBill Taylor * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
28*9e39c5baSBill Taylor * Use is subject to license terms.
29*9e39c5baSBill Taylor */
30*9e39c5baSBill Taylor
31*9e39c5baSBill Taylor /*
32*9e39c5baSBill Taylor *
33*9e39c5baSBill Taylor * MODULE: dapl_ring_buffer_util.c
34*9e39c5baSBill Taylor *
35*9e39c5baSBill Taylor * PURPOSE: Ring buffer management
36*9e39c5baSBill Taylor * Description: Support and management functions for ring buffers
37*9e39c5baSBill Taylor *
38*9e39c5baSBill Taylor * $Id: dapl_ring_buffer_util.c,v 1.9 2003/07/08 14:23:35 sjs2 Exp $
39*9e39c5baSBill Taylor */
40*9e39c5baSBill Taylor
41*9e39c5baSBill Taylor #include "dapl_ring_buffer_util.h"
42*9e39c5baSBill Taylor
43*9e39c5baSBill Taylor /*
44*9e39c5baSBill Taylor * dapls_rbuf_alloc
45*9e39c5baSBill Taylor *
46*9e39c5baSBill Taylor * Given a DAPL_RING_BUFFER, initialize it and provide memory for
47*9e39c5baSBill Taylor * the ringbuf itself. A passed in size will be adjusted to the next
48*9e39c5baSBill Taylor * largest power of two number to simplify management.
49*9e39c5baSBill Taylor *
50*9e39c5baSBill Taylor * Input:
51*9e39c5baSBill Taylor * rbuf pointer to DAPL_RING_BUFFER
52*9e39c5baSBill Taylor * size number of elements to allocate & manage
53*9e39c5baSBill Taylor *
54*9e39c5baSBill Taylor * Output:
55*9e39c5baSBill Taylor * none
56*9e39c5baSBill Taylor *
57*9e39c5baSBill Taylor * Returns:
58*9e39c5baSBill Taylor * DAT_SUCCESS
59*9e39c5baSBill Taylor * DAT_INSUFFICIENT_RESOURCES
60*9e39c5baSBill Taylor *
61*9e39c5baSBill Taylor */
62*9e39c5baSBill Taylor DAT_RETURN
dapls_rbuf_alloc(INOUT DAPL_RING_BUFFER * rbuf,IN DAT_COUNT size)63*9e39c5baSBill Taylor dapls_rbuf_alloc(
64*9e39c5baSBill Taylor INOUT DAPL_RING_BUFFER *rbuf,
65*9e39c5baSBill Taylor IN DAT_COUNT size)
66*9e39c5baSBill Taylor {
67*9e39c5baSBill Taylor unsigned int rsize; /* real size */
68*9e39c5baSBill Taylor
69*9e39c5baSBill Taylor /*
70*9e39c5baSBill Taylor * The circular buffer must be allocated one too large.
71*9e39c5baSBill Taylor * This eliminates any need for a distinct counter, as that
72*9e39c5baSBill Taylor * having the two pointers equal always means "empty" -- never "full"
73*9e39c5baSBill Taylor */
74*9e39c5baSBill Taylor size++;
75*9e39c5baSBill Taylor
76*9e39c5baSBill Taylor /* Put size on a power of 2 boundary */
77*9e39c5baSBill Taylor rsize = 1;
78*9e39c5baSBill Taylor while ((DAT_COUNT)rsize < size) {
79*9e39c5baSBill Taylor rsize <<= 1;
80*9e39c5baSBill Taylor }
81*9e39c5baSBill Taylor
82*9e39c5baSBill Taylor rbuf->base = (void *) dapl_os_alloc(rsize * sizeof (void *));
83*9e39c5baSBill Taylor if (rbuf->base != NULL) {
84*9e39c5baSBill Taylor rbuf->lim = rsize - 1;
85*9e39c5baSBill Taylor rbuf->head = 0;
86*9e39c5baSBill Taylor rbuf->tail = 0;
87*9e39c5baSBill Taylor dapl_os_lock_init(&rbuf->lock);
88*9e39c5baSBill Taylor } else {
89*9e39c5baSBill Taylor return (DAT_INSUFFICIENT_RESOURCES | DAT_RESOURCE_MEMORY);
90*9e39c5baSBill Taylor }
91*9e39c5baSBill Taylor
92*9e39c5baSBill Taylor return (DAT_SUCCESS);
93*9e39c5baSBill Taylor }
94*9e39c5baSBill Taylor
95*9e39c5baSBill Taylor
96*9e39c5baSBill Taylor /*
97*9e39c5baSBill Taylor * dapls_rbuf_realloc
98*9e39c5baSBill Taylor *
99*9e39c5baSBill Taylor * Resizes an empty DAPL_RING_BUFFER. This function is not thread safe;
100*9e39c5baSBill Taylor * adding or removing elements from a ring buffer while resizing
101*9e39c5baSBill Taylor * will have indeterminate results.
102*9e39c5baSBill Taylor *
103*9e39c5baSBill Taylor * Input:
104*9e39c5baSBill Taylor * rbuf pointer to DAPL_RING_BUFFER
105*9e39c5baSBill Taylor * size number of elements to allocate & manage
106*9e39c5baSBill Taylor *
107*9e39c5baSBill Taylor * Output:
108*9e39c5baSBill Taylor * none
109*9e39c5baSBill Taylor *
110*9e39c5baSBill Taylor * Returns:
111*9e39c5baSBill Taylor * DAT_SUCCESS
112*9e39c5baSBill Taylor * DAT_INVALID_STATE
113*9e39c5baSBill Taylor * DAT_INSUFFICIENT_RESOURCES
114*9e39c5baSBill Taylor *
115*9e39c5baSBill Taylor */
116*9e39c5baSBill Taylor DAT_RETURN
dapls_rbuf_realloc(INOUT DAPL_RING_BUFFER * rbuf,IN DAT_COUNT size)117*9e39c5baSBill Taylor dapls_rbuf_realloc(
118*9e39c5baSBill Taylor INOUT DAPL_RING_BUFFER *rbuf,
119*9e39c5baSBill Taylor IN DAT_COUNT size)
120*9e39c5baSBill Taylor {
121*9e39c5baSBill Taylor int rsize; /* real size */
122*9e39c5baSBill Taylor DAT_RETURN dat_status;
123*9e39c5baSBill Taylor
124*9e39c5baSBill Taylor dat_status = DAT_SUCCESS;
125*9e39c5baSBill Taylor
126*9e39c5baSBill Taylor /* if the ring buffer is not empty */
127*9e39c5baSBill Taylor if (rbuf->head != rbuf->tail) {
128*9e39c5baSBill Taylor dat_status = DAT_ERROR(DAT_INVALID_STATE, 0);
129*9e39c5baSBill Taylor goto bail;
130*9e39c5baSBill Taylor }
131*9e39c5baSBill Taylor
132*9e39c5baSBill Taylor /* Put size on a power of 2 boundary */
133*9e39c5baSBill Taylor rsize = 1;
134*9e39c5baSBill Taylor while (rsize < size) {
135*9e39c5baSBill Taylor rsize <<= 1;
136*9e39c5baSBill Taylor }
137*9e39c5baSBill Taylor
138*9e39c5baSBill Taylor rbuf->base = (void *)dapl_os_realloc(rbuf->base,
139*9e39c5baSBill Taylor rsize * sizeof (void *));
140*9e39c5baSBill Taylor if (NULL == rbuf->base) {
141*9e39c5baSBill Taylor dat_status = DAT_ERROR(DAT_INSUFFICIENT_RESOURCES,
142*9e39c5baSBill Taylor DAT_RESOURCE_MEMORY);
143*9e39c5baSBill Taylor goto bail;
144*9e39c5baSBill Taylor }
145*9e39c5baSBill Taylor
146*9e39c5baSBill Taylor rbuf->lim = rsize - 1;
147*9e39c5baSBill Taylor
148*9e39c5baSBill Taylor bail:
149*9e39c5baSBill Taylor return (dat_status);
150*9e39c5baSBill Taylor }
151*9e39c5baSBill Taylor
152*9e39c5baSBill Taylor
153*9e39c5baSBill Taylor /*
154*9e39c5baSBill Taylor * dapls_rbuf_destroy
155*9e39c5baSBill Taylor *
156*9e39c5baSBill Taylor * Release the buffer and reset pointers to a DAPL_RING_BUFFER
157*9e39c5baSBill Taylor *
158*9e39c5baSBill Taylor * Input:
159*9e39c5baSBill Taylor * rbuf pointer to DAPL_RING_BUFFER
160*9e39c5baSBill Taylor *
161*9e39c5baSBill Taylor * Output:
162*9e39c5baSBill Taylor * none
163*9e39c5baSBill Taylor *
164*9e39c5baSBill Taylor * Returns:
165*9e39c5baSBill Taylor * none
166*9e39c5baSBill Taylor *
167*9e39c5baSBill Taylor */
168*9e39c5baSBill Taylor void
dapls_rbuf_destroy(IN DAPL_RING_BUFFER * rbuf)169*9e39c5baSBill Taylor dapls_rbuf_destroy(
170*9e39c5baSBill Taylor IN DAPL_RING_BUFFER *rbuf)
171*9e39c5baSBill Taylor {
172*9e39c5baSBill Taylor if ((NULL == rbuf) ||
173*9e39c5baSBill Taylor (NULL == rbuf->base)) {
174*9e39c5baSBill Taylor return;
175*9e39c5baSBill Taylor }
176*9e39c5baSBill Taylor
177*9e39c5baSBill Taylor dapl_os_lock_destroy(&rbuf->lock);
178*9e39c5baSBill Taylor dapl_os_free(rbuf->base, (rbuf->lim + 1) * sizeof (void *));
179*9e39c5baSBill Taylor rbuf->base = NULL;
180*9e39c5baSBill Taylor rbuf->lim = 0;
181*9e39c5baSBill Taylor }
182*9e39c5baSBill Taylor
183*9e39c5baSBill Taylor /*
184*9e39c5baSBill Taylor * dapls_rbuf_add
185*9e39c5baSBill Taylor *
186*9e39c5baSBill Taylor * Add an entry to the ring buffer
187*9e39c5baSBill Taylor *
188*9e39c5baSBill Taylor * Input:
189*9e39c5baSBill Taylor * rbuf pointer to DAPL_RING_BUFFER
190*9e39c5baSBill Taylor * entry entry to add
191*9e39c5baSBill Taylor *
192*9e39c5baSBill Taylor * Output:
193*9e39c5baSBill Taylor * none
194*9e39c5baSBill Taylor *
195*9e39c5baSBill Taylor * Returns:
196*9e39c5baSBill Taylor * DAT_SUCCESS
197*9e39c5baSBill Taylor * DAT_INSUFFICIENT_RESOURCES (queue full)
198*9e39c5baSBill Taylor *
199*9e39c5baSBill Taylor */
200*9e39c5baSBill Taylor DAT_RETURN
dapls_rbuf_add(IN DAPL_RING_BUFFER * rbuf,IN void * entry)201*9e39c5baSBill Taylor dapls_rbuf_add(
202*9e39c5baSBill Taylor IN DAPL_RING_BUFFER *rbuf,
203*9e39c5baSBill Taylor IN void *entry)
204*9e39c5baSBill Taylor {
205*9e39c5baSBill Taylor DAPL_ATOMIC pos;
206*9e39c5baSBill Taylor
207*9e39c5baSBill Taylor dapl_os_lock(&rbuf->lock);
208*9e39c5baSBill Taylor pos = rbuf->head;
209*9e39c5baSBill Taylor if (((pos + 1) & rbuf->lim) != rbuf->tail) {
210*9e39c5baSBill Taylor rbuf->base[pos] = entry;
211*9e39c5baSBill Taylor rbuf->head = (pos + 1) & rbuf->lim;
212*9e39c5baSBill Taylor dapl_os_unlock(&rbuf->lock);
213*9e39c5baSBill Taylor return (DAT_SUCCESS);
214*9e39c5baSBill Taylor }
215*9e39c5baSBill Taylor
216*9e39c5baSBill Taylor dapl_os_unlock(&rbuf->lock);
217*9e39c5baSBill Taylor return (DAT_ERROR(DAT_INSUFFICIENT_RESOURCES, DAT_RESOURCE_MEMORY));
218*9e39c5baSBill Taylor }
219*9e39c5baSBill Taylor
220*9e39c5baSBill Taylor
221*9e39c5baSBill Taylor /*
222*9e39c5baSBill Taylor * dapls_rbuf_remove
223*9e39c5baSBill Taylor *
224*9e39c5baSBill Taylor * Remove an entry from the ring buffer
225*9e39c5baSBill Taylor *
226*9e39c5baSBill Taylor * Input:
227*9e39c5baSBill Taylor * rbuf pointer to DAPL_RING_BUFFER
228*9e39c5baSBill Taylor *
229*9e39c5baSBill Taylor * Output:
230*9e39c5baSBill Taylor * entry entry removed from the ring buffer
231*9e39c5baSBill Taylor *
232*9e39c5baSBill Taylor * Returns:
233*9e39c5baSBill Taylor * a pointer to a buffer entry
234*9e39c5baSBill Taylor */
235*9e39c5baSBill Taylor void *
dapls_rbuf_remove(IN DAPL_RING_BUFFER * rbuf)236*9e39c5baSBill Taylor dapls_rbuf_remove(
237*9e39c5baSBill Taylor IN DAPL_RING_BUFFER *rbuf)
238*9e39c5baSBill Taylor {
239*9e39c5baSBill Taylor DAPL_ATOMIC pos;
240*9e39c5baSBill Taylor
241*9e39c5baSBill Taylor dapl_os_lock(&rbuf->lock);
242*9e39c5baSBill Taylor if (rbuf->head != rbuf->tail) {
243*9e39c5baSBill Taylor pos = rbuf->tail;
244*9e39c5baSBill Taylor rbuf->tail = (pos + 1) & rbuf->lim;
245*9e39c5baSBill Taylor dapl_os_unlock(&rbuf->lock);
246*9e39c5baSBill Taylor return (rbuf->base[pos]);
247*9e39c5baSBill Taylor }
248*9e39c5baSBill Taylor
249*9e39c5baSBill Taylor dapl_os_unlock(&rbuf->lock);
250*9e39c5baSBill Taylor return (NULL);
251*9e39c5baSBill Taylor }
252*9e39c5baSBill Taylor
253*9e39c5baSBill Taylor
254*9e39c5baSBill Taylor /*
255*9e39c5baSBill Taylor * dapli_rbuf_count
256*9e39c5baSBill Taylor *
257*9e39c5baSBill Taylor * Return the number of entries in use in the ring buffer
258*9e39c5baSBill Taylor *
259*9e39c5baSBill Taylor * Input:
260*9e39c5baSBill Taylor * rbuf pointer to DAPL_RING_BUFFER
261*9e39c5baSBill Taylor *
262*9e39c5baSBill Taylor * Output:
263*9e39c5baSBill Taylor * none
264*9e39c5baSBill Taylor *
265*9e39c5baSBill Taylor * Returns:
266*9e39c5baSBill Taylor * count of entries
267*9e39c5baSBill Taylor *
268*9e39c5baSBill Taylor */
269*9e39c5baSBill Taylor DAT_COUNT
dapls_rbuf_count(IN DAPL_RING_BUFFER * rbuf)270*9e39c5baSBill Taylor dapls_rbuf_count(
271*9e39c5baSBill Taylor IN DAPL_RING_BUFFER *rbuf)
272*9e39c5baSBill Taylor {
273*9e39c5baSBill Taylor int head;
274*9e39c5baSBill Taylor int tail;
275*9e39c5baSBill Taylor
276*9e39c5baSBill Taylor dapl_os_lock(&rbuf->lock);
277*9e39c5baSBill Taylor head = rbuf->head;
278*9e39c5baSBill Taylor tail = rbuf->tail;
279*9e39c5baSBill Taylor dapl_os_unlock(&rbuf->lock);
280*9e39c5baSBill Taylor if (head == tail)
281*9e39c5baSBill Taylor return (0);
282*9e39c5baSBill Taylor if (head > tail)
283*9e39c5baSBill Taylor return (head - tail);
284*9e39c5baSBill Taylor /* add 1 to lim as it is a mask, number of entries - 1 */
285*9e39c5baSBill Taylor return ((rbuf->lim + 1 - tail + head));
286*9e39c5baSBill Taylor }
287