FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_queue.h
1 /*-
2 * CAM request queue management definitions.
3 *
4 * Copyright (c) 1997 Justin T. Gibbs.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
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.
15 *
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
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: releng/10.1/sys/cam/cam_queue.h 260387 2014-01-07 01:51:48Z scottl $
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 */
48 struct camq {
49 cam_pinfo **queue_array;
50 int array_size;
51 int entries;
52 u_int32_t generation;
53 u_int32_t qfrozen_cnt;
54 };
55
56 TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
57 LIST_HEAD(ccb_hdr_list, ccb_hdr);
58 SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
59
60 struct 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 devq_openings;
66 int dev_openings;
67 int dev_active;
68 int held;
69 };
70
71 struct cam_ed;
72
73 struct cam_devq {
74 struct mtx send_mtx;
75 struct camq send_queue;
76 int send_openings;
77 int send_active;
78 };
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 * Allocate and initialize a cam_queue structure.
105 */
106 struct camq *camq_alloc(int size);
107
108 /*
109 * Resize a cam queue
110 */
111 u_int32_t camq_resize(struct camq *queue, int new_size);
112
113 /*
114 * Initialize a camq structure. Return 0 on success, 1 on failure.
115 */
116 int camq_init(struct camq *camq, int size);
117
118 /*
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.
122 */
123 void camq_free(struct camq *queue);
124
125 /*
126 * Finialize any internal storage or state of a cam_queue.
127 */
128 void camq_fini(struct camq *queue);
129
130 /*
131 * cam_queue_insert: Given a CAM queue with at least one open spot,
132 * insert the new entry maintaining order.
133 */
134 void camq_insert(struct camq *queue, cam_pinfo *new_entry);
135
136 /*
137 * camq_remove: Remove and arbitrary entry from the queue maintaining
138 * queue order.
139 */
140 cam_pinfo *camq_remove(struct camq *queue, int index);
141 #define CAMQ_HEAD 1 /* Head of queue index */
142
143 /* Index the first element in the heap */
144 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
145
146 /* Get the first element priority. */
147 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
148 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
149
150 /*
151 * camq_change_priority: Raise or lower the priority of an entry
152 * maintaining queue order.
153 */
154 void camq_change_priority(struct camq *queue, int index,
155 u_int32_t new_priority);
156
157 static __inline int
158 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
159
160 static __inline void
161 cam_ccbq_take_opening(struct cam_ccbq *ccbq);
162
163 static __inline void
164 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
165
166 static __inline void
167 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
168
169 static __inline union ccb *
170 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
171
172 static __inline void
173 cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
174
175 static __inline void
176 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
177
178 static __inline void
179 cam_ccbq_release_opening(struct cam_ccbq *ccbq);
180
181
182 static __inline int
183 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
184 {
185 return (ccbq->queue.entries + ccbq->queue_extra_entries);
186 }
187
188 static __inline void
189 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
190 {
191 ccbq->devq_openings--;
192 ccbq->held++;
193 }
194
195 static __inline void
196 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
197 {
198 struct ccb_hdr *old_ccb;
199 struct camq *queue = &ccbq->queue;
200
201 ccbq->held--;
202
203 /*
204 * If queue is already full, try to resize.
205 * If resize fail, push CCB with lowest priority out to the TAILQ.
206 */
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,
211 xpt_links.tqe);
212 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
213 ccbq->queue_extra_entries++;
214 }
215
216 camq_insert(queue, &new_ccb->ccb_h.pinfo);
217 }
218
219 static __inline void
220 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
221 {
222 struct ccb_hdr *cccb, *bccb;
223 struct camq *queue = &ccbq->queue;
224
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,
228 xpt_links.tqe);
229 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
230 ccbq->queue_extra_entries--;
231 return;
232 }
233
234 camq_remove(queue, ccb->ccb_h.pinfo.index);
235
236 /*
237 * If there are some CCBs on TAILQ, find the best one and move it
238 * to the emptied space in the queue.
239 */
240 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
241 if (bccb == NULL)
242 return;
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)))
248 bccb = cccb;
249 }
250 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
251 ccbq->queue_extra_entries--;
252 camq_insert(queue, &bccb->pinfo);
253 }
254
255 static __inline union ccb *
256 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
257 {
258 return((union ccb *)ccbq->queue.queue_array[index]);
259 }
260
261 static __inline void
262 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
263 {
264
265 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
266 ccbq->dev_active++;
267 ccbq->dev_openings--;
268 }
269
270 static __inline void
271 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
272 {
273
274 ccbq->dev_active--;
275 ccbq->dev_openings++;
276 ccbq->held++;
277 }
278
279 static __inline void
280 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
281 {
282 ccbq->held--;
283 ccbq->devq_openings++;
284 }
285
286 #endif /* _KERNEL */
287 #endif /* _CAM_CAM_QUEUE_H */
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