FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_queue.c
1 /*-
2 * CAM request queue management functions.
3 *
4 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/types.h>
37 #include <sys/malloc.h>
38 #include <sys/kernel.h>
39
40 #include <cam/cam.h>
41 #include <cam/cam_ccb.h>
42 #include <cam/cam_queue.h>
43 #include <cam/cam_debug.h>
44
45 static MALLOC_DEFINE(M_CAMQ, "CAM queue", "CAM queue buffers");
46 static MALLOC_DEFINE(M_CAMDEVQ, "CAM dev queue", "CAM dev queue buffers");
47 static MALLOC_DEFINE(M_CAMCCBQ, "CAM ccb queue", "CAM ccb queue buffers");
48
49 static void heap_up(cam_pinfo **queue_array, int new_index);
50 static void heap_down(cam_pinfo **queue_array, int index,
51 int last_index);
52
53 int
54 camq_init(struct camq *camq, int size)
55 {
56 bzero(camq, sizeof(*camq));
57 camq->array_size = size;
58 if (camq->array_size != 0) {
59 /*
60 * Heap algorithms like everything numbered from 1, so
61 * allocate one more to account for 0 base.
62 */
63 camq->queue_array = malloc((size + 1) * sizeof(cam_pinfo*),
64 M_CAMQ, M_NOWAIT);
65 if (camq->queue_array == NULL) {
66 printf("camq_init: - cannot malloc array!\n");
67 return (1);
68 }
69 }
70 return (0);
71 }
72
73 /*
74 * Free a camq structure. This should only be called if a controller
75 * driver fails somehow during its attach routine or is unloaded and has
76 * obtained a camq structure. The XPT should ensure that the queue
77 * is empty before calling this routine.
78 */
79 void
80 camq_fini(struct camq *queue)
81 {
82 if (queue->queue_array != NULL) {
83 free(queue->queue_array, M_CAMQ);
84 }
85 }
86
87 u_int32_t
88 camq_resize(struct camq *queue, int new_size)
89 {
90 cam_pinfo **new_array;
91
92 KASSERT(new_size >= queue->entries, ("camq_resize: "
93 "New queue size can't accommodate queued entries (%d < %d).",
94 new_size, queue->entries));
95 new_array = malloc((new_size + 1) * sizeof(cam_pinfo *), M_CAMQ,
96 M_NOWAIT);
97 if (new_array == NULL) {
98 /* Couldn't satisfy request */
99 return (CAM_RESRC_UNAVAIL);
100 }
101 /*
102 * Heap algorithms like everything numbered from 1, so
103 * remember that our pointer into the heap array is offset
104 * by one element.
105 */
106 if (queue->queue_array != NULL) {
107 bcopy(queue->queue_array, new_array,
108 (queue->entries + 1) * sizeof(cam_pinfo *));
109 free(queue->queue_array, M_CAMQ);
110 }
111 queue->queue_array = new_array;
112 queue->array_size = new_size;
113 return (CAM_REQ_CMP);
114 }
115
116 /*
117 * camq_insert: Given an array of cam_pinfo* elememnts with
118 * the Heap(1, num_elements) property and array_size - num_elements >= 1,
119 * output Heap(1, num_elements+1) including new_entry in the array.
120 */
121 void
122 camq_insert(struct camq *queue, cam_pinfo *new_entry)
123 {
124
125 KASSERT(queue->entries < queue->array_size,
126 ("camq_insert: Attempt to insert into a full queue (%d >= %d)",
127 queue->entries, queue->array_size));
128 queue->entries++;
129 queue->queue_array[queue->entries] = new_entry;
130 new_entry->index = queue->entries;
131 if (queue->entries != 0)
132 heap_up(queue->queue_array, queue->entries);
133 }
134
135 /*
136 * camq_remove: Given an array of cam_pinfo* elevements with the
137 * Heap(1, num_elements) property and an index such that 1 <= index <=
138 * num_elements, remove that entry and restore the Heap(1, num_elements-1)
139 * property.
140 */
141 cam_pinfo *
142 camq_remove(struct camq *queue, int index)
143 {
144 cam_pinfo *removed_entry;
145
146 if (index <= 0 || index > queue->entries)
147 panic("%s: Attempt to remove out-of-bounds index %d "
148 "from queue %p of size %d", __func__, index, queue,
149 queue->entries);
150
151 removed_entry = queue->queue_array[index];
152 if (queue->entries != index) {
153 queue->queue_array[index] = queue->queue_array[queue->entries];
154 queue->queue_array[index]->index = index;
155 heap_down(queue->queue_array, index, queue->entries - 1);
156 }
157 removed_entry->index = CAM_UNQUEUED_INDEX;
158 queue->entries--;
159 return (removed_entry);
160 }
161
162 /*
163 * camq_change_priority: Given an array of cam_pinfo* elements with the
164 * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements,
165 * and a new priority for the element at index, change the priority of
166 * element index and restore the Heap(0, num_elements) property.
167 */
168 void
169 camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
170 {
171 if (new_priority > queue->queue_array[index]->priority) {
172 queue->queue_array[index]->priority = new_priority;
173 heap_down(queue->queue_array, index, queue->entries);
174 } else {
175 /* new_priority <= old_priority */
176 queue->queue_array[index]->priority = new_priority;
177 heap_up(queue->queue_array, index);
178 }
179 }
180
181 struct cam_devq *
182 cam_devq_alloc(int devices, int openings)
183 {
184 struct cam_devq *devq;
185
186 devq = (struct cam_devq *)malloc(sizeof(*devq), M_CAMDEVQ, M_NOWAIT);
187 if (devq == NULL) {
188 printf("cam_devq_alloc: - cannot malloc!\n");
189 return (NULL);
190 }
191 if (cam_devq_init(devq, devices, openings) != 0) {
192 free(devq, M_CAMDEVQ);
193 return (NULL);
194 }
195 return (devq);
196 }
197
198 int
199 cam_devq_init(struct cam_devq *devq, int devices, int openings)
200 {
201
202 bzero(devq, sizeof(*devq));
203 mtx_init(&devq->send_mtx, "CAM queue lock", NULL, MTX_DEF);
204 if (camq_init(&devq->send_queue, devices) != 0)
205 return (1);
206 devq->send_openings = openings;
207 devq->send_active = 0;
208 return (0);
209 }
210
211 void
212 cam_devq_free(struct cam_devq *devq)
213 {
214
215 camq_fini(&devq->send_queue);
216 mtx_destroy(&devq->send_mtx);
217 free(devq, M_CAMDEVQ);
218 }
219
220 u_int32_t
221 cam_devq_resize(struct cam_devq *camq, int devices)
222 {
223 u_int32_t retval;
224
225 retval = camq_resize(&camq->send_queue, devices);
226 return (retval);
227 }
228
229 struct cam_ccbq *
230 cam_ccbq_alloc(int openings)
231 {
232 struct cam_ccbq *ccbq;
233
234 ccbq = (struct cam_ccbq *)malloc(sizeof(*ccbq), M_CAMCCBQ, M_NOWAIT);
235 if (ccbq == NULL) {
236 printf("cam_ccbq_alloc: - cannot malloc!\n");
237 return (NULL);
238 }
239 if (cam_ccbq_init(ccbq, openings) != 0) {
240 free(ccbq, M_CAMCCBQ);
241 return (NULL);
242 }
243
244 return (ccbq);
245 }
246
247 void
248 cam_ccbq_free(struct cam_ccbq *ccbq)
249 {
250 if (ccbq) {
251 cam_ccbq_fini(ccbq);
252 free(ccbq, M_CAMCCBQ);
253 }
254 }
255
256 u_int32_t
257 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
258 {
259 int delta;
260
261 delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
262 ccbq->total_openings += delta;
263 ccbq->dev_openings += delta;
264
265 new_size = imax(64, 1 << fls(new_size + new_size / 2));
266 if (new_size > ccbq->queue.array_size)
267 return (camq_resize(&ccbq->queue, new_size));
268 else
269 return (CAM_REQ_CMP);
270 }
271
272 int
273 cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
274 {
275 bzero(ccbq, sizeof(*ccbq));
276 if (camq_init(&ccbq->queue,
277 imax(64, 1 << fls(openings + openings / 2))) != 0)
278 return (1);
279 ccbq->total_openings = openings;
280 ccbq->dev_openings = openings;
281 return (0);
282 }
283
284 void
285 cam_ccbq_fini(struct cam_ccbq *ccbq)
286 {
287
288 camq_fini(&ccbq->queue);
289 }
290
291 /*
292 * Heap routines for manipulating CAM queues.
293 */
294 /*
295 * queue_cmp: Given an array of cam_pinfo* elements and indexes i
296 * and j, return less than 0, 0, or greater than 0 if i is less than,
297 * equal too, or greater than j respectively.
298 */
299 static __inline int
300 queue_cmp(cam_pinfo **queue_array, int i, int j)
301 {
302 if (queue_array[i]->priority == queue_array[j]->priority)
303 return ( queue_array[i]->generation
304 - queue_array[j]->generation );
305 else
306 return ( queue_array[i]->priority
307 - queue_array[j]->priority );
308 }
309
310 /*
311 * swap: Given an array of cam_pinfo* elements and indexes i and j,
312 * exchange elements i and j.
313 */
314 static __inline void
315 swap(cam_pinfo **queue_array, int i, int j)
316 {
317 cam_pinfo *temp_qentry;
318
319 temp_qentry = queue_array[j];
320 queue_array[j] = queue_array[i];
321 queue_array[i] = temp_qentry;
322 queue_array[j]->index = j;
323 queue_array[i]->index = i;
324 }
325
326 /*
327 * heap_up: Given an array of cam_pinfo* elements with the
328 * Heap(1, new_index-1) property and a new element in location
329 * new_index, output Heap(1, new_index).
330 */
331 static void
332 heap_up(cam_pinfo **queue_array, int new_index)
333 {
334 int child;
335 int parent;
336
337 child = new_index;
338
339 while (child != 1) {
340 parent = child >> 1;
341 if (queue_cmp(queue_array, parent, child) <= 0)
342 break;
343 swap(queue_array, parent, child);
344 child = parent;
345 }
346 }
347
348 /*
349 * heap_down: Given an array of cam_pinfo* elements with the
350 * Heap(index + 1, num_entries) property with index containing
351 * an unsorted entry, output Heap(index, num_entries).
352 */
353 static void
354 heap_down(cam_pinfo **queue_array, int index, int num_entries)
355 {
356 int child;
357 int parent;
358
359 parent = index;
360 child = parent << 1;
361 for (; child <= num_entries; child = parent << 1) {
362 if (child < num_entries) {
363 /* child+1 is the right child of parent */
364 if (queue_cmp(queue_array, child + 1, child) < 0)
365 child++;
366 }
367 /* child is now the least child of parent */
368 if (queue_cmp(queue_array, parent, child) <= 0)
369 break;
370 swap(queue_array, child, parent);
371 parent = child;
372 }
373 }
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