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;
75 struct camq send_queue;
81 struct cam_devq *cam_devq_alloc(int devices, int openings);
83 int cam_devq_init(struct cam_devq *devq, int devices,
86 void cam_devq_free(struct cam_devq *devq);
88 u_int32_t cam_devq_resize(struct cam_devq *camq, int openings);
91 * Allocate a cam_ccb_queue structure and initialize it.
93 struct cam_ccbq *cam_ccbq_alloc(int openings);
95 u_int32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
97 int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
99 void cam_ccbq_free(struct cam_ccbq *ccbq);
101 void cam_ccbq_fini(struct cam_ccbq *ccbq);
104 * Allocate and initialize a cam_queue structure.
106 struct camq *camq_alloc(int size);
111 u_int32_t camq_resize(struct camq *queue, int new_size);
114 * Initialize a camq structure. Return 0 on success, 1 on failure.
116 int camq_init(struct camq *camq, int size);
119 * Free a cam_queue structure. This should only be called if a controller
120 * driver failes somehow during its attach routine or is unloaded and has
121 * obtained a cam_queue structure.
123 void camq_free(struct camq *queue);
126 * Finialize any internal storage or state of a cam_queue.
128 void camq_fini(struct camq *queue);
131 * cam_queue_insert: Given a CAM queue with at least one open spot,
132 * insert the new entry maintaining order.
134 void camq_insert(struct camq *queue, cam_pinfo *new_entry);
137 * camq_remove: Remove and arbitrary entry from the queue maintaining
140 cam_pinfo *camq_remove(struct camq *queue, int index);
141 #define CAMQ_HEAD 1 /* Head of queue index */
143 /* Index the first element in the heap */
144 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
146 /* Get the first element priority. */
147 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
148 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
151 * camq_change_priority: Raise or lower the priority of an entry
152 * maintaining queue order.
154 void camq_change_priority(struct camq *queue, int index,
155 u_int32_t new_priority);
158 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
161 cam_ccbq_take_opening(struct cam_ccbq *ccbq);
164 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
167 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
169 static __inline union ccb *
170 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
173 cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
176 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
179 cam_ccbq_release_opening(struct cam_ccbq *ccbq);
183 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
185 return (ccbq->queue.entries + ccbq->queue_extra_entries);
189 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
191 ccbq->devq_openings--;
196 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
198 struct ccb_hdr *old_ccb;
199 struct camq *queue = &ccbq->queue;
204 * If queue is already full, try to resize.
205 * If resize fail, push CCB with lowest priority out to the TAILQ.
207 if (queue->entries == queue->array_size &&
208 camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
209 old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
210 TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
212 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
213 ccbq->queue_extra_entries++;
216 camq_insert(queue, &new_ccb->ccb_h.pinfo);
220 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
222 struct ccb_hdr *cccb, *bccb;
223 struct camq *queue = &ccbq->queue;
225 /* If the CCB is on the TAILQ, remove it from there. */
226 if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
227 TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
229 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
230 ccbq->queue_extra_entries--;
234 camq_remove(queue, ccb->ccb_h.pinfo.index);
237 * If there are some CCBs on TAILQ, find the best one and move it
238 * to the emptied space in the queue.
240 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
243 TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
244 if (bccb->pinfo.priority > cccb->pinfo.priority ||
245 (bccb->pinfo.priority == cccb->pinfo.priority &&
246 GENERATIONCMP(bccb->pinfo.generation, >,
247 cccb->pinfo.generation)))
250 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
251 ccbq->queue_extra_entries--;
252 camq_insert(queue, &bccb->pinfo);
255 static __inline union ccb *
256 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
258 return((union ccb *)ccbq->queue.queue_array[index]);
262 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
265 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
267 ccbq->dev_openings--;
271 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
275 ccbq->dev_openings++;
280 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
283 ccbq->devq_openings++;
287 #endif /* _CAM_CAM_QUEUE_H */