xref: /illumos-gate/usr/src/uts/intel/io/dktp/hba/ghd/ghd_queue.c (revision 581cede61ac9c14d8d4ea452562a567189eead78)
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 1999 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 
30 #include <sys/types.h>
31 #include <sys/param.h>
32 #include <sys/debug.h>
33 #include "ghd_queue.h"
34 
35 
36 
37 void
38 L1_add(L1_t *lp, L1el_t *lep, void *datap)
39 {
40 	/* init the list element */
41 	lep->le_nextp = NULL;
42 	lep->le_datap = datap;
43 
44 	if (!lp->l1_tailp) {
45 		/* list is empty */
46 		lp->l1_headp = lep;
47 	} else {
48 		/* add it to the tailend */
49 		lp->l1_tailp->le_nextp = lep;
50 	}
51 
52 	lp->l1_tailp = lep;
53 }
54 
55 
56 /*
57  * L1Delete()
58  *
59  *	Remove a specific entry from a singly-linked list.
60  *
61  */
62 
63 void
64 L1_delete(L1_t *lp, L1el_t *lep)
65 {
66 	L1el_t	*prevp;
67 
68 	if (lp->l1_headp == lep) {
69 		/* it's the first entry in the list */
70 		if ((lp->l1_headp = lep->le_nextp) == NULL) {
71 			/* the list is now empty */
72 			lp->l1_tailp = NULL;
73 		}
74 		return;
75 	}
76 
77 	for (prevp = lp->l1_headp; prevp != NULL; prevp = prevp->le_nextp) {
78 		if (prevp->le_nextp == lep) {
79 			if ((prevp->le_nextp = lep->le_nextp) == NULL)
80 				lp->l1_tailp = prevp;
81 			return;
82 		}
83 	}
84 	/* its not on this list */
85 }
86 
87 
88 /*
89  * L1_remove()
90  *
91  *	Remove the entry at the head of the list (if any).
92  *
93  */
94 
95 void *
96 L1_remove(L1_t *lp)
97 {
98 	L1el_t	*lep;
99 
100 	/* pop the first one off the list head */
101 	if ((lep = lp->l1_headp) == NULL) {
102 		return (NULL);
103 	}
104 
105 	/* if the list is now empty fix the tail pointer */
106 	if ((lp->l1_headp = lep->le_nextp) == NULL)
107 		lp->l1_tailp = NULL;
108 
109 	lep->le_nextp = NULL;
110 
111 	return (lep->le_datap);
112 }
113 
114 
115 void
116 L2_add(L2el_t *headp, L2el_t *elementp, void *private)
117 {
118 
119 	ASSERT(headp != NULL && elementp != NULL);
120 	ASSERT(headp->l2_nextp != NULL);
121 	ASSERT(headp->l2_prevp != NULL);
122 
123 	elementp->l2_private = private;
124 
125 	elementp->l2_nextp = headp;
126 	elementp->l2_prevp = headp->l2_prevp;
127 	headp->l2_prevp->l2_nextp = elementp;
128 	headp->l2_prevp = elementp;
129 }
130 
131 void
132 L2_delete(L2el_t *elementp)
133 {
134 
135 	ASSERT(elementp != NULL);
136 	ASSERT(elementp->l2_nextp != NULL);
137 	ASSERT(elementp->l2_prevp != NULL);
138 	ASSERT(elementp->l2_nextp->l2_prevp == elementp);
139 	ASSERT(elementp->l2_prevp->l2_nextp == elementp);
140 
141 	elementp->l2_prevp->l2_nextp = elementp->l2_nextp;
142 	elementp->l2_nextp->l2_prevp = elementp->l2_prevp;
143 
144 	/* link it to itself in case someone does a double delete */
145 	elementp->l2_nextp = elementp;
146 	elementp->l2_prevp = elementp;
147 }
148 
149 
150 void
151 L2_add_head(L2el_t *headp, L2el_t *elementp, void *private)
152 {
153 
154 	ASSERT(headp != NULL && elementp != NULL);
155 	ASSERT(headp->l2_nextp != NULL);
156 	ASSERT(headp->l2_prevp != NULL);
157 
158 	elementp->l2_private = private;
159 
160 	elementp->l2_prevp = headp;
161 	elementp->l2_nextp = headp->l2_nextp;
162 	headp->l2_nextp->l2_prevp = elementp;
163 	headp->l2_nextp = elementp;
164 }
165 
166 
167 
168 /*
169  * L2_remove()
170  *
171  *	Remove the entry from the head of the list (if any).
172  *
173  */
174 
175 void *
176 L2_remove_head(L2el_t *headp)
177 {
178 	L2el_t *elementp;
179 
180 	ASSERT(headp != NULL);
181 
182 	if (L2_EMPTY(headp))
183 		return (NULL);
184 
185 	elementp = headp->l2_nextp;
186 
187 	headp->l2_nextp = elementp->l2_nextp;
188 	elementp->l2_nextp->l2_prevp = headp;
189 
190 	/* link it to itself in case someone does a double delete */
191 	elementp->l2_nextp = elementp;
192 	elementp->l2_prevp = elementp;
193 
194 	return (elementp->l2_private);
195 }
196 
197 void *
198 L2_next(L2el_t *elementp)
199 {
200 
201 	ASSERT(elementp != NULL);
202 
203 	if (L2_EMPTY(elementp))
204 		return (NULL);
205 	return (elementp->l2_nextp->l2_private);
206 }
207