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/10.3/sys/cam/cam_queue.c 273078 2014-10-14 12:13:01Z 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
43static MALLOC_DEFINE(M_CAMQ, "CAM queue", "CAM queue buffers");
44static MALLOC_DEFINE(M_CAMDEVQ, "CAM dev queue", "CAM dev queue buffers");
45static MALLOC_DEFINE(M_CAMCCBQ, "CAM ccb queue", "CAM ccb queue buffers");
46
47static __inline int
48		queue_cmp(cam_pinfo **queue_array, int i, int j);
49static __inline void
50		swap(cam_pinfo **queue_array, int i, int j);
51static void	heap_up(cam_pinfo **queue_array, int new_index);
52static void	heap_down(cam_pinfo **queue_array, int index,
53			  int last_index);
54
55struct camq *
56camq_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
70int
71camq_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 */
97void
98camq_free(struct camq *queue)
99{
100	if (queue != NULL) {
101		camq_fini(queue);
102		free(queue, M_CAMQ);
103	}
104}
105
106void
107camq_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
119u_int32_t
120camq_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 */
154void
155camq_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 */
174cam_pinfo *
175camq_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 */
198void
199camq_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
211struct cam_devq *
212cam_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	return (devq);
226}
227
228int
229cam_devq_init(struct cam_devq *devq, int devices, int openings)
230{
231
232	bzero(devq, sizeof(*devq));
233	mtx_init(&devq->send_mtx, "CAM queue lock", NULL, MTX_DEF);
234	if (camq_init(&devq->send_queue, devices) != 0)
235		return (1);
236	devq->send_openings = openings;
237	devq->send_active = 0;
238	return (0);
239}
240
241void
242cam_devq_free(struct cam_devq *devq)
243{
244
245	camq_fini(&devq->send_queue);
246	mtx_destroy(&devq->send_mtx);
247	free(devq, M_CAMDEVQ);
248}
249
250u_int32_t
251cam_devq_resize(struct cam_devq *camq, int devices)
252{
253	u_int32_t retval;
254
255	retval = camq_resize(&camq->send_queue, devices);
256	return (retval);
257}
258
259struct cam_ccbq *
260cam_ccbq_alloc(int openings)
261{
262	struct cam_ccbq *ccbq;
263
264	ccbq = (struct cam_ccbq *)malloc(sizeof(*ccbq), M_CAMCCBQ, M_NOWAIT);
265	if (ccbq == NULL) {
266		printf("cam_ccbq_alloc: - cannot malloc!\n");
267		return (NULL);
268	}
269	if (cam_ccbq_init(ccbq, openings) != 0) {
270		free(ccbq, M_CAMCCBQ);
271		return (NULL);
272	}
273
274	return (ccbq);
275}
276
277void
278cam_ccbq_free(struct cam_ccbq *ccbq)
279{
280	if (ccbq) {
281		cam_ccbq_fini(ccbq);
282		free(ccbq, M_CAMCCBQ);
283	}
284}
285
286u_int32_t
287cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
288{
289	int delta;
290
291	delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
292	ccbq->total_openings += delta;
293	ccbq->dev_openings += delta;
294
295	new_size = imax(64, 1 << fls(new_size + new_size / 2));
296	if (new_size > ccbq->queue.array_size)
297		return (camq_resize(&ccbq->queue, new_size));
298	else
299		return (CAM_REQ_CMP);
300}
301
302int
303cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
304{
305	bzero(ccbq, sizeof(*ccbq));
306	if (camq_init(&ccbq->queue,
307	    imax(64, 1 << fls(openings + openings / 2))) != 0)
308		return (1);
309	ccbq->total_openings = openings;
310	ccbq->dev_openings = openings;
311	return (0);
312}
313
314void
315cam_ccbq_fini(struct cam_ccbq *ccbq)
316{
317
318	camq_fini(&ccbq->queue);
319}
320
321/*
322 * Heap routines for manipulating CAM queues.
323 */
324/*
325 * queue_cmp: Given an array of cam_pinfo* elements and indexes i
326 * and j, return less than 0, 0, or greater than 0 if i is less than,
327 * equal too, or greater than j respectively.
328 */
329static __inline int
330queue_cmp(cam_pinfo **queue_array, int i, int j)
331{
332	if (queue_array[i]->priority == queue_array[j]->priority)
333		return (  queue_array[i]->generation
334			- queue_array[j]->generation );
335	else
336		return (  queue_array[i]->priority
337			- queue_array[j]->priority );
338}
339
340/*
341 * swap: Given an array of cam_pinfo* elements and indexes i and j,
342 * exchange elements i and j.
343 */
344static __inline void
345swap(cam_pinfo **queue_array, int i, int j)
346{
347	cam_pinfo *temp_qentry;
348
349	temp_qentry = queue_array[j];
350	queue_array[j] = queue_array[i];
351	queue_array[i] = temp_qentry;
352	queue_array[j]->index = j;
353	queue_array[i]->index = i;
354}
355
356/*
357 * heap_up:  Given an array of cam_pinfo* elements with the
358 * Heap(1, new_index-1) property and a new element in location
359 * new_index, output Heap(1, new_index).
360 */
361static void
362heap_up(cam_pinfo **queue_array, int new_index)
363{
364	int child;
365	int parent;
366
367	child = new_index;
368
369	while (child != 1) {
370
371		parent = child >> 1;
372		if (queue_cmp(queue_array, parent, child) <= 0)
373			break;
374		swap(queue_array, parent, child);
375		child = parent;
376	}
377}
378
379/*
380 * heap_down:  Given an array of cam_pinfo* elements with the
381 * Heap(index + 1, num_entries) property with index containing
382 * an unsorted entry, output Heap(index, num_entries).
383 */
384static void
385heap_down(cam_pinfo **queue_array, int index, int num_entries)
386{
387	int child;
388	int parent;
389
390	parent = index;
391	child = parent << 1;
392	for (; child <= num_entries; child = parent << 1) {
393
394		if (child < num_entries) {
395			/* child+1 is the right child of parent */
396			if (queue_cmp(queue_array, child + 1, child) < 0)
397				child++;
398		}
399		/* child is now the least child of parent */
400		if (queue_cmp(queue_array, parent, child) <= 0)
401			break;
402		swap(queue_array, child, parent);
403		parent = child;
404	}
405}
406