FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_queue.c
1 /*-
2 * CAM request queue management functions.
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
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/9.2/sys/cam/cam_queue.c 249132 2013-04-05 08:22:11Z mav $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/types.h>
35 #include <sys/malloc.h>
36 #include <sys/kernel.h>
37
38 #include <cam/cam.h>
39 #include <cam/cam_ccb.h>
40 #include <cam/cam_queue.h>
41 #include <cam/cam_debug.h>
42
43 static MALLOC_DEFINE(M_CAMQ, "CAM queue", "CAM queue buffers");
44 static MALLOC_DEFINE(M_CAMDEVQ, "CAM dev queue", "CAM dev queue buffers");
45 static MALLOC_DEFINE(M_CAMCCBQ, "CAM ccb queue", "CAM ccb queue buffers");
46
47 static __inline int
48 queue_cmp(cam_pinfo **queue_array, int i, int j);
49 static __inline void
50 swap(cam_pinfo **queue_array, int i, int j);
51 static void heap_up(cam_pinfo **queue_array, int new_index);
52 static void heap_down(cam_pinfo **queue_array, int index,
53 int last_index);
54
55 struct camq *
56 camq_alloc(int size)
57 {
58 struct camq *camq;
59
60 camq = (struct camq *)malloc(sizeof(*camq), M_CAMQ, M_NOWAIT);
61 if (camq != NULL) {
62 if (camq_init(camq, size) != 0) {
63 free(camq, M_CAMQ);
64 camq = NULL;
65 }
66 }
67 return (camq);
68 }
69
70 int
71 camq_init(struct camq *camq, int size)
72 {
73 bzero(camq, sizeof(*camq));
74 camq->array_size = size;
75 if (camq->array_size != 0) {
76 camq->queue_array = (cam_pinfo**)malloc(size*sizeof(cam_pinfo*),
77 M_CAMQ, M_NOWAIT);
78 if (camq->queue_array == NULL) {
79 printf("camq_init: - cannot malloc array!\n");
80 return (1);
81 }
82 /*
83 * Heap algorithms like everything numbered from 1, so
84 * offset our pointer into the heap array by one element.
85 */
86 camq->queue_array--;
87 }
88 return (0);
89 }
90
91 /*
92 * Free a camq structure. This should only be called if a controller
93 * driver failes somehow during its attach routine or is unloaded and has
94 * obtained a camq structure. The XPT should ensure that the queue
95 * is empty before calling this routine.
96 */
97 void
98 camq_free(struct camq *queue)
99 {
100 if (queue != NULL) {
101 camq_fini(queue);
102 free(queue, M_CAMQ);
103 }
104 }
105
106 void
107 camq_fini(struct camq *queue)
108 {
109 if (queue->queue_array != NULL) {
110 /*
111 * Heap algorithms like everything numbered from 1, so
112 * our pointer into the heap array is offset by one element.
113 */
114 queue->queue_array++;
115 free(queue->queue_array, M_CAMQ);
116 }
117 }
118
119 u_int32_t
120 camq_resize(struct camq *queue, int new_size)
121 {
122 cam_pinfo **new_array;
123
124 KASSERT(new_size >= queue->entries, ("camq_resize: "
125 "New queue size can't accomodate queued entries (%d < %d).",
126 new_size, queue->entries));
127 new_array = (cam_pinfo **)malloc(new_size * sizeof(cam_pinfo *),
128 M_CAMQ, M_NOWAIT);
129 if (new_array == NULL) {
130 /* Couldn't satisfy request */
131 return (CAM_RESRC_UNAVAIL);
132 }
133 /*
134 * Heap algorithms like everything numbered from 1, so
135 * remember that our pointer into the heap array is offset
136 * by one element.
137 */
138 if (queue->queue_array != NULL) {
139 queue->queue_array++;
140 bcopy(queue->queue_array, new_array,
141 queue->entries * sizeof(cam_pinfo *));
142 free(queue->queue_array, M_CAMQ);
143 }
144 queue->queue_array = new_array-1;
145 queue->array_size = new_size;
146 return (CAM_REQ_CMP);
147 }
148
149 /*
150 * camq_insert: Given an array of cam_pinfo* elememnts with
151 * the Heap(1, num_elements) property and array_size - num_elements >= 1,
152 * output Heap(1, num_elements+1) including new_entry in the array.
153 */
154 void
155 camq_insert(struct camq *queue, cam_pinfo *new_entry)
156 {
157
158 KASSERT(queue->entries < queue->array_size,
159 ("camq_insert: Attempt to insert into a full queue (%d >= %d)",
160 queue->entries, queue->array_size));
161 queue->entries++;
162 queue->queue_array[queue->entries] = new_entry;
163 new_entry->index = queue->entries;
164 if (queue->entries != 0)
165 heap_up(queue->queue_array, queue->entries);
166 }
167
168 /*
169 * camq_remove: Given an array of cam_pinfo* elevements with the
170 * Heap(1, num_elements) property and an index such that 1 <= index <=
171 * num_elements, remove that entry and restore the Heap(1, num_elements-1)
172 * property.
173 */
174 cam_pinfo *
175 camq_remove(struct camq *queue, int index)
176 {
177 cam_pinfo *removed_entry;
178
179 if (index == 0 || index > queue->entries)
180 return (NULL);
181 removed_entry = queue->queue_array[index];
182 if (queue->entries != index) {
183 queue->queue_array[index] = queue->queue_array[queue->entries];
184 queue->queue_array[index]->index = index;
185 heap_down(queue->queue_array, index, queue->entries - 1);
186 }
187 removed_entry->index = CAM_UNQUEUED_INDEX;
188 queue->entries--;
189 return (removed_entry);
190 }
191
192 /*
193 * camq_change_priority: Given an array of cam_pinfo* elements with the
194 * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements,
195 * and a new priority for the element at index, change the priority of
196 * element index and restore the Heap(0, num_elements) property.
197 */
198 void
199 camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
200 {
201 if (new_priority > queue->queue_array[index]->priority) {
202 queue->queue_array[index]->priority = new_priority;
203 heap_down(queue->queue_array, index, queue->entries);
204 } else {
205 /* new_priority <= old_priority */
206 queue->queue_array[index]->priority = new_priority;
207 heap_up(queue->queue_array, index);
208 }
209 }
210
211 struct cam_devq *
212 cam_devq_alloc(int devices, int openings)
213 {
214 struct cam_devq *devq;
215
216 devq = (struct cam_devq *)malloc(sizeof(*devq), M_CAMDEVQ, M_NOWAIT);
217 if (devq == NULL) {
218 printf("cam_devq_alloc: - cannot malloc!\n");
219 return (NULL);
220 }
221 if (cam_devq_init(devq, devices, openings) != 0) {
222 free(devq, M_CAMDEVQ);
223 return (NULL);
224 }
225
226 return (devq);
227 }
228
229 int
230 cam_devq_init(struct cam_devq *devq, int devices, int openings)
231 {
232 bzero(devq, sizeof(*devq));
233 if (camq_init(&devq->alloc_queue, devices) != 0) {
234 return (1);
235 }
236 if (camq_init(&devq->send_queue, devices) != 0) {
237 camq_fini(&devq->alloc_queue);
238 return (1);
239 }
240 devq->alloc_openings = openings;
241 devq->alloc_active = 0;
242 devq->send_openings = openings;
243 devq->send_active = 0;
244 return (0);
245 }
246
247 void
248 cam_devq_free(struct cam_devq *devq)
249 {
250 camq_fini(&devq->alloc_queue);
251 camq_fini(&devq->send_queue);
252 free(devq, M_CAMDEVQ);
253 }
254
255 u_int32_t
256 cam_devq_resize(struct cam_devq *camq, int devices)
257 {
258 u_int32_t retval;
259
260 retval = camq_resize(&camq->alloc_queue, devices);
261
262 if (retval == CAM_REQ_CMP)
263 retval = camq_resize(&camq->send_queue, devices);
264
265 return (retval);
266 }
267
268 struct cam_ccbq *
269 cam_ccbq_alloc(int openings)
270 {
271 struct cam_ccbq *ccbq;
272
273 ccbq = (struct cam_ccbq *)malloc(sizeof(*ccbq), M_CAMCCBQ, M_NOWAIT);
274 if (ccbq == NULL) {
275 printf("cam_ccbq_alloc: - cannot malloc!\n");
276 return (NULL);
277 }
278 if (cam_ccbq_init(ccbq, openings) != 0) {
279 free(ccbq, M_CAMCCBQ);
280 return (NULL);
281 }
282
283 return (ccbq);
284 }
285
286 void
287 cam_ccbq_free(struct cam_ccbq *ccbq)
288 {
289 if (ccbq) {
290 cam_ccbq_fini(ccbq);
291 free(ccbq, M_CAMCCBQ);
292 }
293 }
294
295 u_int32_t
296 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
297 {
298 int delta;
299 int space_left;
300
301 delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
302 space_left = new_size
303 - ccbq->queue.entries
304 - ccbq->held
305 - ccbq->dev_active;
306
307 /*
308 * Only attempt to change the underlying queue size if we are
309 * shrinking it and there is space for all outstanding entries
310 * in the new array or we have been requested to grow the array.
311 * We don't fail in the case where we can't reduce the array size,
312 * but clients that care that the queue be "garbage collected"
313 * should detect this condition and call us again with the
314 * same size once the outstanding entries have been processed.
315 */
316 if (space_left < 0
317 || camq_resize(&ccbq->queue, new_size + (CAM_RL_VALUES - 1)) ==
318 CAM_REQ_CMP) {
319 ccbq->devq_openings += delta;
320 ccbq->dev_openings += delta;
321 return (CAM_REQ_CMP);
322 } else {
323 return (CAM_RESRC_UNAVAIL);
324 }
325 }
326
327 int
328 cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
329 {
330 bzero(ccbq, sizeof(*ccbq));
331 if (camq_init(&ccbq->queue, openings + (CAM_RL_VALUES - 1)) != 0) {
332 return (1);
333 }
334 ccbq->devq_openings = openings;
335 ccbq->dev_openings = openings;
336 return (0);
337 }
338
339 void
340 cam_ccbq_fini(struct cam_ccbq *ccbq)
341 {
342
343 camq_fini(&ccbq->queue);
344 }
345
346 /*
347 * Heap routines for manipulating CAM queues.
348 */
349 /*
350 * queue_cmp: Given an array of cam_pinfo* elements and indexes i
351 * and j, return less than 0, 0, or greater than 0 if i is less than,
352 * equal too, or greater than j respectively.
353 */
354 static __inline int
355 queue_cmp(cam_pinfo **queue_array, int i, int j)
356 {
357 if (queue_array[i]->priority == queue_array[j]->priority)
358 return ( queue_array[i]->generation
359 - queue_array[j]->generation );
360 else
361 return ( queue_array[i]->priority
362 - queue_array[j]->priority );
363 }
364
365 /*
366 * swap: Given an array of cam_pinfo* elements and indexes i and j,
367 * exchange elements i and j.
368 */
369 static __inline void
370 swap(cam_pinfo **queue_array, int i, int j)
371 {
372 cam_pinfo *temp_qentry;
373
374 temp_qentry = queue_array[j];
375 queue_array[j] = queue_array[i];
376 queue_array[i] = temp_qentry;
377 queue_array[j]->index = j;
378 queue_array[i]->index = i;
379 }
380
381 /*
382 * heap_up: Given an array of cam_pinfo* elements with the
383 * Heap(1, new_index-1) property and a new element in location
384 * new_index, output Heap(1, new_index).
385 */
386 static void
387 heap_up(cam_pinfo **queue_array, int new_index)
388 {
389 int child;
390 int parent;
391
392 child = new_index;
393
394 while (child != 1) {
395
396 parent = child >> 1;
397 if (queue_cmp(queue_array, parent, child) <= 0)
398 break;
399 swap(queue_array, parent, child);
400 child = parent;
401 }
402 }
403
404 /*
405 * heap_down: Given an array of cam_pinfo* elements with the
406 * Heap(index + 1, num_entries) property with index containing
407 * an unsorted entry, output Heap(index, num_entries).
408 */
409 static void
410 heap_down(cam_pinfo **queue_array, int index, int num_entries)
411 {
412 int child;
413 int parent;
414
415 parent = index;
416 child = parent << 1;
417 for (; child <= num_entries; child = parent << 1) {
418
419 if (child < num_entries) {
420 /* child+1 is the right child of parent */
421 if (queue_cmp(queue_array, child + 1, child) < 0)
422 child++;
423 }
424 /* child is now the least child of parent */
425 if (queue_cmp(queue_array, parent, child) <= 0)
426 break;
427 swap(queue_array, child, parent);
428 parent = child;
429 }
430 }
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