2 * CAM request queue management definitions.
4 * Copyright (c) 1997 Justin T. Gibbs.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions, and the following disclaimer,
12 * without modification, immediately at the beginning of the file.
13 * 2. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * 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;
53 u_int32_t qfrozen_cnt;
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;
80 struct cam_devq *cam_devq_alloc(int devices, int openings);
82 int cam_devq_init(struct cam_devq *devq, int devices,
85 void cam_devq_free(struct cam_devq *devq);
87 u_int32_t cam_devq_resize(struct cam_devq *camq, int openings);
90 * Allocate a cam_ccb_queue structure and initialize it.
92 struct cam_ccbq *cam_ccbq_alloc(int openings);
94 u_int32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
96 int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
98 void cam_ccbq_free(struct cam_ccbq *ccbq);
100 void cam_ccbq_fini(struct cam_ccbq *ccbq);
103 * Allocate and initialize a cam_queue structure.
105 struct camq *camq_alloc(int size);
110 u_int32_t camq_resize(struct camq *queue, int new_size);
113 * Initialize a camq structure. Return 0 on success, 1 on failure.
115 int camq_init(struct camq *camq, int size);
118 * Free a cam_queue structure. This should only be called if a controller
119 * driver failes somehow during its attach routine or is unloaded and has
120 * obtained a cam_queue structure.
122 void camq_free(struct camq *queue);
125 * Finialize any internal storage or state of a cam_queue.
127 void camq_fini(struct camq *queue);
130 * cam_queue_insert: Given a CAM queue with at least one open spot,
131 * insert the new entry maintaining order.
133 void camq_insert(struct camq *queue, cam_pinfo *new_entry);
136 * camq_remove: Remove and arbitrary entry from the queue maintaining
139 cam_pinfo *camq_remove(struct camq *queue, int index);
140 #define CAMQ_HEAD 1 /* Head of queue index */
142 /* Index the first element in the heap */
143 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
145 /* Get the first element priority. */
146 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
147 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
150 * camq_change_priority: Raise or lower the priority of an entry
151 * maintaining queue order.
153 void camq_change_priority(struct camq *queue, int index,
154 u_int32_t new_priority);
157 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
160 cam_ccbq_take_opening(struct cam_ccbq *ccbq);
163 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
166 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
168 static __inline union ccb *
169 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
172 cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
175 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
178 cam_ccbq_release_opening(struct cam_ccbq *ccbq);
182 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
184 return (ccbq->queue.entries + ccbq->queue_extra_entries);
188 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
195 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
197 struct ccb_hdr *old_ccb;
198 struct camq *queue = &ccbq->queue;
201 * If queue is already full, try to resize.
202 * If resize fail, push CCB with lowest priority out to the TAILQ.
204 if (queue->entries == queue->array_size &&
205 camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
206 old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
207 TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
209 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
210 ccbq->queue_extra_entries++;
213 camq_insert(queue, &new_ccb->ccb_h.pinfo);
217 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
219 struct ccb_hdr *cccb, *bccb;
220 struct camq *queue = &ccbq->queue;
222 /* If the CCB is on the TAILQ, remove it from there. */
223 if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
224 TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
226 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
227 ccbq->queue_extra_entries--;
231 camq_remove(queue, ccb->ccb_h.pinfo.index);
234 * If there are some CCBs on TAILQ, find the best one and move it
235 * to the emptied space in the queue.
237 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
240 TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
241 if (bccb->pinfo.priority > cccb->pinfo.priority ||
242 (bccb->pinfo.priority == cccb->pinfo.priority &&
243 GENERATIONCMP(bccb->pinfo.generation, >,
244 cccb->pinfo.generation)))
247 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
248 ccbq->queue_extra_entries--;
249 camq_insert(queue, &bccb->pinfo);
252 static __inline union ccb *
253 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
255 return((union ccb *)ccbq->queue.queue_array[index]);
259 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
262 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
264 ccbq->dev_openings--;
268 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
272 ccbq->dev_openings++;
276 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
283 #endif /* _CAM_CAM_QUEUE_H */