FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_queue.h
1 /*-
2 * CAM request queue management definitions.
3 *
4 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
5 *
6 * Copyright (c) 1997 Justin T. Gibbs.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions, and the following disclaimer,
14 * without modification, immediately at the beginning of the file.
15 * 2. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32
33 #ifndef _CAM_CAM_QUEUE_H
34 #define _CAM_CAM_QUEUE_H 1
35
36 #ifdef _KERNEL
37
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/queue.h>
41 #include <cam/cam.h>
42
43 /*
44 * This structure implements a heap based priority queue. The queue
45 * assumes that the objects stored in it begin with a cam_qentry
46 * structure holding the priority information used to sort the objects.
47 * This structure is opaque to clients (outside of the XPT layer) to allow
48 * the implementation to change without affecting them.
49 */
50 struct camq {
51 cam_pinfo **queue_array;
52 int array_size;
53 int entries;
54 u_int32_t generation;
55 u_int32_t qfrozen_cnt;
56 };
57
58 TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
59 LIST_HEAD(ccb_hdr_list, ccb_hdr);
60 SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
61
62 struct cam_ccbq {
63 struct camq queue;
64 struct ccb_hdr_tailq queue_extra_head;
65 int queue_extra_entries;
66 int total_openings;
67 int allocated;
68 int dev_openings;
69 int dev_active;
70 };
71
72 struct cam_ed;
73
74 struct cam_devq {
75 struct mtx send_mtx;
76 struct camq send_queue;
77 int send_openings;
78 int send_active;
79 };
80
81 struct cam_devq *cam_devq_alloc(int devices, int openings);
82
83 int cam_devq_init(struct cam_devq *devq, int devices,
84 int openings);
85
86 void cam_devq_free(struct cam_devq *devq);
87
88 u_int32_t cam_devq_resize(struct cam_devq *camq, int openings);
89
90 /*
91 * Allocate a cam_ccb_queue structure and initialize it.
92 */
93 struct cam_ccbq *cam_ccbq_alloc(int openings);
94
95 u_int32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
96
97 int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
98
99 void cam_ccbq_free(struct cam_ccbq *ccbq);
100
101 void cam_ccbq_fini(struct cam_ccbq *ccbq);
102
103 /*
104 * Resize a cam queue
105 */
106 u_int32_t camq_resize(struct camq *queue, int new_size);
107
108 /*
109 * Initialize a camq structure. Return 0 on success, 1 on failure.
110 */
111 int camq_init(struct camq *camq, int size);
112
113 /*
114 * Finialize any internal storage or state of a cam_queue.
115 */
116 void camq_fini(struct camq *queue);
117
118 /*
119 * cam_queue_insert: Given a CAM queue with at least one open spot,
120 * insert the new entry maintaining order.
121 */
122 void camq_insert(struct camq *queue, cam_pinfo *new_entry);
123
124 /*
125 * camq_remove: Remove and arbitrary entry from the queue maintaining
126 * queue order.
127 */
128 cam_pinfo *camq_remove(struct camq *queue, int index);
129 #define CAMQ_HEAD 1 /* Head of queue index */
130
131 /* Index the first element in the heap */
132 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
133
134 /* Get the first element priority. */
135 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
136 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
137
138 /*
139 * camq_change_priority: Raise or lower the priority of an entry
140 * maintaining queue order.
141 */
142 void camq_change_priority(struct camq *queue, int index,
143 u_int32_t new_priority);
144
145 static __inline int
146 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
147 {
148 return (ccbq->queue.entries + ccbq->queue_extra_entries);
149 }
150
151 static __inline void
152 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
153 {
154
155 ccbq->allocated++;
156 }
157
158 static __inline void
159 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
160 {
161 struct ccb_hdr *old_ccb;
162 struct camq *queue = &ccbq->queue;
163
164 KASSERT((new_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0 &&
165 (new_ccb->ccb_h.func_code & XPT_FC_USER_CCB) == 0,
166 ("%s: Cannot queue ccb %p func_code %#x", __func__, new_ccb,
167 new_ccb->ccb_h.func_code));
168
169 /*
170 * If queue is already full, try to resize.
171 * If resize fail, push CCB with lowest priority out to the TAILQ.
172 */
173 if (queue->entries == queue->array_size &&
174 camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
175 old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
176 TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
177 xpt_links.tqe);
178 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
179 ccbq->queue_extra_entries++;
180 }
181
182 camq_insert(queue, &new_ccb->ccb_h.pinfo);
183 }
184
185 static __inline void
186 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
187 {
188 struct ccb_hdr *cccb, *bccb;
189 struct camq *queue = &ccbq->queue;
190 cam_pinfo *removed_entry __unused;
191
192 /* If the CCB is on the TAILQ, remove it from there. */
193 if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
194 TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
195 xpt_links.tqe);
196 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
197 ccbq->queue_extra_entries--;
198 return;
199 }
200
201 removed_entry = camq_remove(queue, ccb->ccb_h.pinfo.index);
202 KASSERT(removed_entry == &ccb->ccb_h.pinfo,
203 ("%s: Removed wrong entry from queue (%p != %p)", __func__,
204 removed_entry, &ccb->ccb_h.pinfo));
205
206 /*
207 * If there are some CCBs on TAILQ, find the best one and move it
208 * to the emptied space in the queue.
209 */
210 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
211 if (bccb == NULL)
212 return;
213 TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
214 if (bccb->pinfo.priority > cccb->pinfo.priority ||
215 (bccb->pinfo.priority == cccb->pinfo.priority &&
216 GENERATIONCMP(bccb->pinfo.generation, >,
217 cccb->pinfo.generation)))
218 bccb = cccb;
219 }
220 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
221 ccbq->queue_extra_entries--;
222 camq_insert(queue, &bccb->pinfo);
223 }
224
225 static __inline union ccb *
226 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
227 {
228 return((union ccb *)ccbq->queue.queue_array[index]);
229 }
230
231 static __inline void
232 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
233 {
234
235 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
236 ccbq->dev_active++;
237 ccbq->dev_openings--;
238 }
239
240 static __inline void
241 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
242 {
243
244 ccbq->dev_active--;
245 ccbq->dev_openings++;
246 }
247
248 static __inline void
249 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
250 {
251
252 ccbq->allocated--;
253 }
254
255 #endif /* _KERNEL */
256 #endif /* _CAM_CAM_QUEUE_H */
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