1/*-
2 * CAM request queue management definitions.
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
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
31#ifndef _CAM_CAM_QUEUE_H
32#define _CAM_CAM_QUEUE_H 1
33
34#ifdef _KERNEL
35
36#include <sys/lock.h>
37#include <sys/mutex.h>
38#include <sys/queue.h>
39#include <cam/cam.h>
40
41/*
42 * This structure implements a heap based priority queue. The queue
43 * assumes that the objects stored in it begin with a cam_qentry
44 * structure holding the priority information used to sort the objects.
45 * This structure is opaque to clients (outside of the XPT layer) to allow
46 * the implementation to change without affecting them.
47 */
48struct camq {
49 cam_pinfo **queue_array;
50 int array_size;
51 int entries;
52 uint32_t generation;
53 uint32_t qfrozen_cnt;
54};
55
56TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
57LIST_HEAD(ccb_hdr_list, ccb_hdr);
58SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
59
60struct cam_ccbq {
61 struct camq queue;
62 struct ccb_hdr_tailq queue_extra_head;
63 int queue_extra_entries;
64 int total_openings;
65 int allocated;
66 int dev_openings;
67 int dev_active;
68};
69
70struct cam_ed;
71
72struct cam_devq {
73 struct mtx send_mtx;
74 struct camq send_queue;
75 int send_openings;
76 int send_active;
77};
78
79struct cam_devq *cam_devq_alloc(int devices, int openings);
80
81int cam_devq_init(struct cam_devq *devq, int devices,
82 int openings);
83
84void cam_devq_free(struct cam_devq *devq);
85
86uint32_t cam_devq_resize(struct cam_devq *camq, int openings);
87
88/*
89 * Allocate a cam_ccb_queue structure and initialize it.
90 */
91struct cam_ccbq *cam_ccbq_alloc(int openings);
92
93uint32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
94
95int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
96
97void cam_ccbq_free(struct cam_ccbq *ccbq);
98
99void cam_ccbq_fini(struct cam_ccbq *ccbq);
100
101/*
102 * Resize a cam queue
103 */
104uint32_t camq_resize(struct camq *queue, int new_size);
105
106/*
107 * Initialize a camq structure. Return 0 on success, 1 on failure.
108 */
109int camq_init(struct camq *camq, int size);
110
111/*
112 * Finialize any internal storage or state of a cam_queue.
113 */
114void camq_fini(struct camq *queue);
115
116/*
117 * cam_queue_insert: Given a CAM queue with at least one open spot,
118 * insert the new entry maintaining order.
119 */
120void camq_insert(struct camq *queue, cam_pinfo *new_entry);
121
122/*
123 * camq_remove: Remove and arbitrary entry from the queue maintaining
124 * queue order.
125 */
126cam_pinfo *camq_remove(struct camq *queue, int index);
127#define CAMQ_HEAD 1 /* Head of queue index */
128
129/* Index the first element in the heap */
130#define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
131
132/* Get the first element priority. */
133#define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
134 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
135
136/*
137 * camq_change_priority: Raise or lower the priority of an entry
138 * maintaining queue order.
139 */
140void camq_change_priority(struct camq *queue, int index,
141 uint32_t new_priority);
142
143static __inline int
144cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
145{
146 return (ccbq->queue.entries + ccbq->queue_extra_entries);
147}
148
149static __inline void
150cam_ccbq_take_opening(struct cam_ccbq *ccbq)
151{
152
153 ccbq->allocated++;
154}
155
156static __inline void
157cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
158{
159 struct ccb_hdr *old_ccb;
160 struct camq *queue = &ccbq->queue;
161
162 KASSERT((new_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0 &&
163 (new_ccb->ccb_h.func_code & XPT_FC_USER_CCB) == 0,
164 ("%s: Cannot queue ccb %p func_code %#x", __func__, new_ccb,
165 new_ccb->ccb_h.func_code));
166
167 /*
168 * If queue is already full, try to resize.
169 * If resize fail, push CCB with lowest priority out to the TAILQ.
170 */
171 if (queue->entries == queue->array_size &&
172 camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
173 old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
174 TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
175 xpt_links.tqe);
176 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
177 ccbq->queue_extra_entries++;
178 }
179
180 camq_insert(queue, &new_ccb->ccb_h.pinfo);
181}
182
183static __inline void
184cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
185{
186 struct ccb_hdr *cccb, *bccb;
187 struct camq *queue = &ccbq->queue;
188 cam_pinfo *removed_entry __unused;
189
190 /* If the CCB is on the TAILQ, remove it from there. */
191 if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
192 TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
193 xpt_links.tqe);
194 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
195 ccbq->queue_extra_entries--;
196 return;
197 }
198
199 removed_entry = camq_remove(queue, ccb->ccb_h.pinfo.index);
200 KASSERT(removed_entry == &ccb->ccb_h.pinfo,
201 ("%s: Removed wrong entry from queue (%p != %p)", __func__,
202 removed_entry, &ccb->ccb_h.pinfo));
203
204 /*
205 * If there are some CCBs on TAILQ, find the best one and move it
206 * to the emptied space in the queue.
207 */
208 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
209 if (bccb == NULL)
210 return;
211 TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
212 if (bccb->pinfo.priority > cccb->pinfo.priority ||
213 (bccb->pinfo.priority == cccb->pinfo.priority &&
214 GENERATIONCMP(bccb->pinfo.generation, >,
215 cccb->pinfo.generation)))
216 bccb = cccb;
217 }
218 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
219 ccbq->queue_extra_entries--;
220 camq_insert(queue, &bccb->pinfo);
221}
222
223static __inline union ccb *
224cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
225{
226 return((union ccb *)ccbq->queue.queue_array[index]);
227}
228
229static __inline void
230cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
231{
232
233 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
234 ccbq->dev_active++;
235 ccbq->dev_openings--;
236}
237
238static __inline void
239cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
240{
241
242 ccbq->dev_active--;
243 ccbq->dev_openings++;
244}
245
246static __inline void
247cam_ccbq_release_opening(struct cam_ccbq *ccbq)
248{
249
250 ccbq->allocated--;
251}
252
253#endif /* _KERNEL */
254#endif /* _CAM_CAM_QUEUE_H */