2 * CAM request queue management functions.
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
28 * $FreeBSD: src/sys/cam/cam_queue.c,v 1.5 1999/08/28 00:40:41 peter Exp $
29 * $DragonFly: src/sys/bus/cam/cam_queue.c,v 1.4 2004/03/12 03:23:13 dillon Exp $
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/types.h>
34 #include <sys/malloc.h>
38 #include "cam_queue.h"
39 #include "cam_debug.h"
42 queue_cmp(cam_pinfo **queue_array, int i, int j);
44 swap(cam_pinfo **queue_array, int i, int j);
45 static void heap_up(cam_pinfo **queue_array, int new_index);
46 static void heap_down(cam_pinfo **queue_array, int index,
54 camq = malloc(sizeof(*camq), M_DEVBUF, M_INTWAIT);
55 camq_init(camq, size);
60 camq_init(struct camq *camq, int size)
62 bzero(camq, sizeof(*camq));
63 camq->array_size = size;
64 if (camq->array_size != 0) {
65 camq->queue_array = malloc(size * sizeof(cam_pinfo *),
68 * Heap algorithms like everything numbered from 1, so
69 * offset our pointer into the heap array by one element.
71 * XXX this is a really dumb idea.
79 * Free a camq structure. This should only be called if a controller
80 * driver failes somehow during its attach routine or is unloaded and has
81 * obtained a camq structure. The XPT should ensure that the queue
82 * is empty before calling this routine.
85 camq_free(struct camq *queue)
89 free(queue, M_DEVBUF);
94 camq_fini(struct camq *queue)
96 if (queue->queue_array != NULL) {
98 * Heap algorithms like everything numbered from 1, so
99 * our pointer into the heap array is offset by one element.
101 queue->queue_array++;
102 free(queue->queue_array, M_DEVBUF);
107 camq_resize(struct camq *queue, int new_size)
109 cam_pinfo **new_array;
112 if (new_size < queue->entries)
113 panic("camq_resize: New queue size can't accomodate "
116 new_array = malloc(new_size * sizeof(cam_pinfo *), M_DEVBUF, M_INTWAIT);
119 * Heap algorithms like everything numbered from 1, so
120 * remember that our pointer into the heap array is offset
123 if (queue->queue_array != NULL) {
124 queue->queue_array++;
125 bcopy(queue->queue_array, new_array,
126 queue->entries * sizeof(cam_pinfo *));
127 free(queue->queue_array, M_DEVBUF);
129 queue->queue_array = new_array-1;
130 queue->array_size = new_size;
131 return (CAM_REQ_CMP);
135 * camq_insert: Given an array of cam_pinfo* elememnts with
136 * the Heap(1, num_elements) property and array_size - num_elements >= 1,
137 * output Heap(1, num_elements+1) including new_entry in the array.
140 camq_insert(struct camq *queue, cam_pinfo *new_entry)
143 if (queue->entries >= queue->array_size)
144 panic("camq_insert: Attempt to insert into a full queue");
147 queue->queue_array[queue->entries] = new_entry;
148 new_entry->index = queue->entries;
149 if (queue->entries != 0)
150 heap_up(queue->queue_array, queue->entries);
154 * camq_remove: Given an array of cam_pinfo* elevements with the
155 * Heap(1, num_elements) property and an index such that 1 <= index <=
156 * num_elements, remove that entry and restore the Heap(1, num_elements-1)
160 camq_remove(struct camq *queue, int index)
162 cam_pinfo *removed_entry;
164 if (index == 0 || index > queue->entries)
166 removed_entry = queue->queue_array[index];
167 if (queue->entries != index) {
168 queue->queue_array[index] = queue->queue_array[queue->entries];
169 queue->queue_array[index]->index = index;
170 heap_down(queue->queue_array, index, queue->entries - 1);
172 removed_entry->index = CAM_UNQUEUED_INDEX;
174 return (removed_entry);
178 * camq_change_priority: Given an array of cam_pinfo* elements with the
179 * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements,
180 * and an new priority for the element at index, change the priority of
181 * element index and restore the Heap(0, num_elements) property.
184 camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
186 if (new_priority > queue->queue_array[index]->priority) {
187 queue->queue_array[index]->priority = new_priority;
188 heap_down(queue->queue_array, index, queue->entries);
190 /* new_priority <= old_priority */
191 queue->queue_array[index]->priority = new_priority;
192 heap_up(queue->queue_array, index);
197 cam_devq_alloc(int devices, int openings)
199 struct cam_devq *devq;
201 devq = malloc(sizeof(*devq), M_DEVBUF, M_INTWAIT);
202 cam_devq_init(devq, devices, openings);
207 cam_devq_init(struct cam_devq *devq, int devices, int openings)
209 bzero(devq, sizeof(*devq));
210 camq_init(&devq->alloc_queue, devices);
211 camq_init(&devq->send_queue, devices);
212 devq->alloc_openings = openings;
213 devq->alloc_active = 0;
214 devq->send_openings = openings;
215 devq->send_active = 0;
220 cam_devq_free(struct cam_devq *devq)
222 camq_fini(&devq->alloc_queue);
223 camq_fini(&devq->send_queue);
224 free(devq, M_DEVBUF);
228 cam_devq_resize(struct cam_devq *camq, int devices)
232 retval = camq_resize(&camq->alloc_queue, devices);
234 if (retval == CAM_REQ_CMP)
235 retval = camq_resize(&camq->send_queue, devices);
241 cam_ccbq_alloc(int openings)
243 struct cam_ccbq *ccbq;
245 ccbq = malloc(sizeof(*ccbq), M_DEVBUF, M_INTWAIT);
246 cam_ccbq_init(ccbq, openings);
251 cam_ccbq_free(struct cam_ccbq *ccbq)
254 camq_fini(&ccbq->queue);
255 free(ccbq, M_DEVBUF);
260 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
265 delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
266 space_left = new_size
267 - ccbq->queue.entries
272 * Only attempt to change the underlying queue size if we are
273 * shrinking it and there is space for all outstanding entries
274 * in the new array or we have been requested to grow the array.
275 * We don't fail in the case where we can't reduce the array size,
276 * but clients that care that the queue be "garbage collected"
277 * should detect this condition and call us again with the
278 * same size once the outstanding entries have been processed.
281 || camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) {
282 ccbq->devq_openings += delta;
283 ccbq->dev_openings += delta;
284 return (CAM_REQ_CMP);
286 return (CAM_RESRC_UNAVAIL);
291 cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
293 bzero(ccbq, sizeof(*ccbq));
294 camq_init(&ccbq->queue, openings);
295 ccbq->devq_openings = openings;
296 ccbq->dev_openings = openings;
297 TAILQ_INIT(&ccbq->active_ccbs);
302 * Heap routines for manipulating CAM queues.
305 * queue_cmp: Given an array of cam_pinfo* elements and indexes i
306 * and j, return less than 0, 0, or greater than 0 if i is less than,
307 * equal too, or greater than j respectively.
310 queue_cmp(cam_pinfo **queue_array, int i, int j)
312 if (queue_array[i]->priority == queue_array[j]->priority)
313 return ( queue_array[i]->generation
314 - queue_array[j]->generation );
316 return ( queue_array[i]->priority
317 - queue_array[j]->priority );
321 * swap: Given an array of cam_pinfo* elements and indexes i and j,
322 * exchange elements i and j.
325 swap(cam_pinfo **queue_array, int i, int j)
327 cam_pinfo *temp_qentry;
329 temp_qentry = queue_array[j];
330 queue_array[j] = queue_array[i];
331 queue_array[i] = temp_qentry;
332 queue_array[j]->index = j;
333 queue_array[i]->index = i;
337 * heap_up: Given an array of cam_pinfo* elements with the
338 * Heap(1, new_index-1) property and a new element in location
339 * new_index, output Heap(1, new_index).
342 heap_up(cam_pinfo **queue_array, int new_index)
352 if (queue_cmp(queue_array, parent, child) <= 0)
354 swap(queue_array, parent, child);
360 * heap_down: Given an array of cam_pinfo* elements with the
361 * Heap(index + 1, num_entries) property with index containing
362 * an unsorted entry, output Heap(index, num_entries).
365 heap_down(cam_pinfo **queue_array, int index, int num_entries)
372 for (; child <= num_entries; child = parent << 1) {
374 if (child < num_entries) {
375 /* child+1 is the right child of parent */
376 if (queue_cmp(queue_array, child + 1, child) < 0)
379 /* child is now the least child of parent */
380 if (queue_cmp(queue_array, parent, child) <= 0)
382 swap(queue_array, child, parent);