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 1.9 2007/05/13 18:33:56 swildner 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 = kmalloc(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 = kmalloc(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 kfree(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 kfree(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 accommodate "
116 new_array = kmalloc(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 kfree(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 = kmalloc(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;
221 cam_devq_reference(struct cam_devq *devq)
227 cam_devq_release(struct cam_devq *devq)
229 if (--devq->refcount == 0) {
230 if (devq->alloc_active || devq->send_active)
231 kprintf("cam_devq_release: WARNING active allocations %d active send %d!\n", devq->alloc_active, devq->send_active);
232 camq_fini(&devq->alloc_queue);
233 camq_fini(&devq->send_queue);
234 kfree(devq, M_DEVBUF);
239 cam_devq_resize(struct cam_devq *camq, int devices)
243 retval = camq_resize(&camq->alloc_queue, devices);
245 if (retval == CAM_REQ_CMP)
246 retval = camq_resize(&camq->send_queue, devices);
252 cam_ccbq_alloc(int openings)
254 struct cam_ccbq *ccbq;
256 ccbq = kmalloc(sizeof(*ccbq), M_DEVBUF, M_INTWAIT);
257 cam_ccbq_init(ccbq, openings);
262 cam_ccbq_free(struct cam_ccbq *ccbq)
265 camq_fini(&ccbq->queue);
266 kfree(ccbq, M_DEVBUF);
271 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
276 delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
277 space_left = new_size
278 - ccbq->queue.entries
283 * Only attempt to change the underlying queue size if we are
284 * shrinking it and there is space for all outstanding entries
285 * in the new array or we have been requested to grow the array.
286 * We don't fail in the case where we can't reduce the array size,
287 * but clients that care that the queue be "garbage collected"
288 * should detect this condition and call us again with the
289 * same size once the outstanding entries have been processed.
292 || camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) {
293 ccbq->devq_openings += delta;
294 ccbq->dev_openings += delta;
295 return (CAM_REQ_CMP);
297 return (CAM_RESRC_UNAVAIL);
302 cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
304 bzero(ccbq, sizeof(*ccbq));
305 camq_init(&ccbq->queue, openings);
306 ccbq->devq_openings = openings;
307 ccbq->dev_openings = openings;
308 TAILQ_INIT(&ccbq->active_ccbs);
313 * Heap routines for manipulating CAM queues.
316 * queue_cmp: Given an array of cam_pinfo* elements and indexes i
317 * and j, return less than 0, 0, or greater than 0 if i is less than,
318 * equal too, or greater than j respectively.
321 queue_cmp(cam_pinfo **queue_array, int i, int j)
323 if (queue_array[i]->priority == queue_array[j]->priority)
324 return ( queue_array[i]->generation
325 - queue_array[j]->generation );
327 return ( queue_array[i]->priority
328 - queue_array[j]->priority );
332 * swap: Given an array of cam_pinfo* elements and indexes i and j,
333 * exchange elements i and j.
336 swap(cam_pinfo **queue_array, int i, int j)
338 cam_pinfo *temp_qentry;
340 temp_qentry = queue_array[j];
341 queue_array[j] = queue_array[i];
342 queue_array[i] = temp_qentry;
343 queue_array[j]->index = j;
344 queue_array[i]->index = i;
348 * heap_up: Given an array of cam_pinfo* elements with the
349 * Heap(1, new_index-1) property and a new element in location
350 * new_index, output Heap(1, new_index).
353 heap_up(cam_pinfo **queue_array, int new_index)
363 if (queue_cmp(queue_array, parent, child) <= 0)
365 swap(queue_array, parent, child);
371 * heap_down: Given an array of cam_pinfo* elements with the
372 * Heap(index + 1, num_entries) property with index containing
373 * an unsorted entry, output Heap(index, num_entries).
376 heap_down(cam_pinfo **queue_array, int index, int num_entries)
383 for (; child <= num_entries; child = parent << 1) {
385 if (child < num_entries) {
386 /* child+1 is the right child of parent */
387 if (queue_cmp(queue_array, child + 1, child) < 0)
390 /* child is now the least child of parent */
391 if (queue_cmp(queue_array, parent, child) <= 0)
393 swap(queue_array, child, parent);