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: stable/11/sys/cam/cam_queue.c 308352 2016-11-05 20:23:18Z markj $");
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 accommodate 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		panic("%s: Attempt to remove out-of-bounds index %d "
181		    "from queue %p of size %d", __func__, index, queue,
182		    queue->entries);
183
184	removed_entry = queue->queue_array[index];
185	if (queue->entries != index) {
186		queue->queue_array[index] = queue->queue_array[queue->entries];
187		queue->queue_array[index]->index = index;
188		heap_down(queue->queue_array, index, queue->entries - 1);
189	}
190	removed_entry->index = CAM_UNQUEUED_INDEX;
191	queue->entries--;
192	return (removed_entry);
193}
194
195/*
196 * camq_change_priority:  Given an array of cam_pinfo* elements with the
197 * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements,
198 * and a new priority for the element at index, change the priority of
199 * element index and restore the Heap(0, num_elements) property.
200 */
201void
202camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
203{
204	if (new_priority > queue->queue_array[index]->priority) {
205		queue->queue_array[index]->priority = new_priority;
206		heap_down(queue->queue_array, index, queue->entries);
207	} else {
208		/* new_priority <= old_priority */
209		queue->queue_array[index]->priority = new_priority;
210		heap_up(queue->queue_array, index);
211	}
212}
213
214struct cam_devq *
215cam_devq_alloc(int devices, int openings)
216{
217	struct cam_devq *devq;
218
219	devq = (struct cam_devq *)malloc(sizeof(*devq), M_CAMDEVQ, M_NOWAIT);
220	if (devq == NULL) {
221		printf("cam_devq_alloc: - cannot malloc!\n");
222		return (NULL);
223	}
224	if (cam_devq_init(devq, devices, openings) != 0) {
225		free(devq, M_CAMDEVQ);
226		return (NULL);
227	}
228	return (devq);
229}
230
231int
232cam_devq_init(struct cam_devq *devq, int devices, int openings)
233{
234
235	bzero(devq, sizeof(*devq));
236	mtx_init(&devq->send_mtx, "CAM queue lock", NULL, MTX_DEF);
237	if (camq_init(&devq->send_queue, devices) != 0)
238		return (1);
239	devq->send_openings = openings;
240	devq->send_active = 0;
241	return (0);
242}
243
244void
245cam_devq_free(struct cam_devq *devq)
246{
247
248	camq_fini(&devq->send_queue);
249	mtx_destroy(&devq->send_mtx);
250	free(devq, M_CAMDEVQ);
251}
252
253u_int32_t
254cam_devq_resize(struct cam_devq *camq, int devices)
255{
256	u_int32_t retval;
257
258	retval = camq_resize(&camq->send_queue, devices);
259	return (retval);
260}
261
262struct cam_ccbq *
263cam_ccbq_alloc(int openings)
264{
265	struct cam_ccbq *ccbq;
266
267	ccbq = (struct cam_ccbq *)malloc(sizeof(*ccbq), M_CAMCCBQ, M_NOWAIT);
268	if (ccbq == NULL) {
269		printf("cam_ccbq_alloc: - cannot malloc!\n");
270		return (NULL);
271	}
272	if (cam_ccbq_init(ccbq, openings) != 0) {
273		free(ccbq, M_CAMCCBQ);
274		return (NULL);
275	}
276
277	return (ccbq);
278}
279
280void
281cam_ccbq_free(struct cam_ccbq *ccbq)
282{
283	if (ccbq) {
284		cam_ccbq_fini(ccbq);
285		free(ccbq, M_CAMCCBQ);
286	}
287}
288
289u_int32_t
290cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
291{
292	int delta;
293
294	delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
295	ccbq->total_openings += delta;
296	ccbq->dev_openings += delta;
297
298	new_size = imax(64, 1 << fls(new_size + new_size / 2));
299	if (new_size > ccbq->queue.array_size)
300		return (camq_resize(&ccbq->queue, new_size));
301	else
302		return (CAM_REQ_CMP);
303}
304
305int
306cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
307{
308	bzero(ccbq, sizeof(*ccbq));
309	if (camq_init(&ccbq->queue,
310	    imax(64, 1 << fls(openings + openings / 2))) != 0)
311		return (1);
312	ccbq->total_openings = openings;
313	ccbq->dev_openings = openings;
314	return (0);
315}
316
317void
318cam_ccbq_fini(struct cam_ccbq *ccbq)
319{
320
321	camq_fini(&ccbq->queue);
322}
323
324/*
325 * Heap routines for manipulating CAM queues.
326 */
327/*
328 * queue_cmp: Given an array of cam_pinfo* elements and indexes i
329 * and j, return less than 0, 0, or greater than 0 if i is less than,
330 * equal too, or greater than j respectively.
331 */
332static __inline int
333queue_cmp(cam_pinfo **queue_array, int i, int j)
334{
335	if (queue_array[i]->priority == queue_array[j]->priority)
336		return (  queue_array[i]->generation
337			- queue_array[j]->generation );
338	else
339		return (  queue_array[i]->priority
340			- queue_array[j]->priority );
341}
342
343/*
344 * swap: Given an array of cam_pinfo* elements and indexes i and j,
345 * exchange elements i and j.
346 */
347static __inline void
348swap(cam_pinfo **queue_array, int i, int j)
349{
350	cam_pinfo *temp_qentry;
351
352	temp_qentry = queue_array[j];
353	queue_array[j] = queue_array[i];
354	queue_array[i] = temp_qentry;
355	queue_array[j]->index = j;
356	queue_array[i]->index = i;
357}
358
359/*
360 * heap_up:  Given an array of cam_pinfo* elements with the
361 * Heap(1, new_index-1) property and a new element in location
362 * new_index, output Heap(1, new_index).
363 */
364static void
365heap_up(cam_pinfo **queue_array, int new_index)
366{
367	int child;
368	int parent;
369
370	child = new_index;
371
372	while (child != 1) {
373
374		parent = child >> 1;
375		if (queue_cmp(queue_array, parent, child) <= 0)
376			break;
377		swap(queue_array, parent, child);
378		child = parent;
379	}
380}
381
382/*
383 * heap_down:  Given an array of cam_pinfo* elements with the
384 * Heap(index + 1, num_entries) property with index containing
385 * an unsorted entry, output Heap(index, num_entries).
386 */
387static void
388heap_down(cam_pinfo **queue_array, int index, int num_entries)
389{
390	int child;
391	int parent;
392
393	parent = index;
394	child = parent << 1;
395	for (; child <= num_entries; child = parent << 1) {
396
397		if (child < num_entries) {
398			/* child+1 is the right child of parent */
399			if (queue_cmp(queue_array, child + 1, child) < 0)
400				child++;
401		}
402		/* child is now the least child of parent */
403		if (queue_cmp(queue_array, parent, child) <= 0)
404			break;
405		swap(queue_array, child, parent);
406		parent = child;
407	}
408}
409