2 * CAM request queue management definitions.
4 * SPDX-License-Identifier: BSD-2-Clause
6 * Copyright (c) 1997 Justin T. Gibbs.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
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.
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
31 #ifndef _CAM_CAM_QUEUE_H
32 #define _CAM_CAM_QUEUE_H 1
37 #include <sys/mutex.h>
38 #include <sys/queue.h>
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.
49 cam_pinfo **queue_array;
56 TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
57 LIST_HEAD(ccb_hdr_list, ccb_hdr);
58 SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
62 struct ccb_hdr_tailq queue_extra_head;
63 int queue_extra_entries;
74 struct camq send_queue;
79 struct cam_devq *cam_devq_alloc(int devices, int openings);
81 int cam_devq_init(struct cam_devq *devq, int devices,
84 void cam_devq_free(struct cam_devq *devq);
86 uint32_t cam_devq_resize(struct cam_devq *camq, int openings);
89 * Allocate a cam_ccb_queue structure and initialize it.
91 struct cam_ccbq *cam_ccbq_alloc(int openings);
93 uint32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
95 int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
97 void cam_ccbq_free(struct cam_ccbq *ccbq);
99 void cam_ccbq_fini(struct cam_ccbq *ccbq);
104 uint32_t camq_resize(struct camq *queue, int new_size);
107 * Initialize a camq structure. Return 0 on success, 1 on failure.
109 int camq_init(struct camq *camq, int size);
112 * Finialize any internal storage or state of a cam_queue.
114 void camq_fini(struct camq *queue);
117 * cam_queue_insert: Given a CAM queue with at least one open spot,
118 * insert the new entry maintaining order.
120 void camq_insert(struct camq *queue, cam_pinfo *new_entry);
123 * camq_remove: Remove and arbitrary entry from the queue maintaining
126 cam_pinfo *camq_remove(struct camq *queue, int index);
127 #define CAMQ_HEAD 1 /* Head of queue index */
129 /* Index the first element in the heap */
130 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
132 /* Get the first element priority. */
133 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
134 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
137 * camq_change_priority: Raise or lower the priority of an entry
138 * maintaining queue order.
140 void camq_change_priority(struct camq *queue, int index,
141 uint32_t new_priority);
144 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
146 return (ccbq->queue.entries + ccbq->queue_extra_entries);
150 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
157 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
159 struct ccb_hdr *old_ccb;
160 struct camq *queue = &ccbq->queue;
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));
168 * If queue is already full, try to resize.
169 * If resize fail, push CCB with lowest priority out to the TAILQ.
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,
176 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
177 ccbq->queue_extra_entries++;
180 camq_insert(queue, &new_ccb->ccb_h.pinfo);
184 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
186 struct ccb_hdr *cccb, *bccb;
187 struct camq *queue = &ccbq->queue;
188 cam_pinfo *removed_entry __unused;
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,
194 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
195 ccbq->queue_extra_entries--;
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));
205 * If there are some CCBs on TAILQ, find the best one and move it
206 * to the emptied space in the queue.
208 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
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)))
218 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
219 ccbq->queue_extra_entries--;
220 camq_insert(queue, &bccb->pinfo);
223 static __inline union ccb *
224 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
226 return((union ccb *)ccbq->queue.queue_array[index]);
230 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
233 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
235 ccbq->dev_openings--;
239 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
243 ccbq->dev_openings++;
247 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
254 #endif /* _CAM_CAM_QUEUE_H */