xref: /freebsd/sys/cam/cam_queue.c (revision d6b92ffa) 
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("$FreeBSD$");
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 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  */
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 		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  */
201 void
202 camq_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 
214 struct cam_devq *
215 cam_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 
231 int
232 cam_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 
244 void
245 cam_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 
253 u_int32_t
254 cam_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 
262 struct cam_ccbq *
263 cam_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 
280 void
281 cam_ccbq_free(struct cam_ccbq *ccbq)
282 {
283 	if (ccbq) {
284 		cam_ccbq_fini(ccbq);
285 		free(ccbq, M_CAMCCBQ);
286 	}
287 }
288 
289 u_int32_t
290 cam_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 
305 int
306 cam_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 
317 void
318 cam_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  */
332 static __inline int
333 queue_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  */
347 static __inline void
348 swap(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  */
364 static void
365 heap_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  */
387 static void
388 heap_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