xref: /linux/sound/core/seq/seq_memory.c (revision 44f57d78) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ALSA sequencer Memory Manager
4  *  Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
5  *                        Jaroslav Kysela <perex@perex.cz>
6  *                2000 by Takashi Iwai <tiwai@suse.de>
7  */
8 
9 #include <linux/init.h>
10 #include <linux/export.h>
11 #include <linux/slab.h>
12 #include <linux/sched/signal.h>
13 #include <linux/mm.h>
14 #include <sound/core.h>
15 
16 #include <sound/seq_kernel.h>
17 #include "seq_memory.h"
18 #include "seq_queue.h"
19 #include "seq_info.h"
20 #include "seq_lock.h"
21 
22 static inline int snd_seq_pool_available(struct snd_seq_pool *pool)
23 {
24 	return pool->total_elements - atomic_read(&pool->counter);
25 }
26 
27 static inline int snd_seq_output_ok(struct snd_seq_pool *pool)
28 {
29 	return snd_seq_pool_available(pool) >= pool->room;
30 }
31 
32 /*
33  * Variable length event:
34  * The event like sysex uses variable length type.
35  * The external data may be stored in three different formats.
36  * 1) kernel space
37  *    This is the normal case.
38  *      ext.data.len = length
39  *      ext.data.ptr = buffer pointer
40  * 2) user space
41  *    When an event is generated via read(), the external data is
42  *    kept in user space until expanded.
43  *      ext.data.len = length | SNDRV_SEQ_EXT_USRPTR
44  *      ext.data.ptr = userspace pointer
45  * 3) chained cells
46  *    When the variable length event is enqueued (in prioq or fifo),
47  *    the external data is decomposed to several cells.
48  *      ext.data.len = length | SNDRV_SEQ_EXT_CHAINED
49  *      ext.data.ptr = the additiona cell head
50  *         -> cell.next -> cell.next -> ..
51  */
52 
53 /*
54  * exported:
55  * call dump function to expand external data.
56  */
57 
58 static int get_var_len(const struct snd_seq_event *event)
59 {
60 	if ((event->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
61 		return -EINVAL;
62 
63 	return event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
64 }
65 
66 int snd_seq_dump_var_event(const struct snd_seq_event *event,
67 			   snd_seq_dump_func_t func, void *private_data)
68 {
69 	int len, err;
70 	struct snd_seq_event_cell *cell;
71 
72 	if ((len = get_var_len(event)) <= 0)
73 		return len;
74 
75 	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
76 		char buf[32];
77 		char __user *curptr = (char __force __user *)event->data.ext.ptr;
78 		while (len > 0) {
79 			int size = sizeof(buf);
80 			if (len < size)
81 				size = len;
82 			if (copy_from_user(buf, curptr, size))
83 				return -EFAULT;
84 			err = func(private_data, buf, size);
85 			if (err < 0)
86 				return err;
87 			curptr += size;
88 			len -= size;
89 		}
90 		return 0;
91 	}
92 	if (!(event->data.ext.len & SNDRV_SEQ_EXT_CHAINED))
93 		return func(private_data, event->data.ext.ptr, len);
94 
95 	cell = (struct snd_seq_event_cell *)event->data.ext.ptr;
96 	for (; len > 0 && cell; cell = cell->next) {
97 		int size = sizeof(struct snd_seq_event);
98 		if (len < size)
99 			size = len;
100 		err = func(private_data, &cell->event, size);
101 		if (err < 0)
102 			return err;
103 		len -= size;
104 	}
105 	return 0;
106 }
107 EXPORT_SYMBOL(snd_seq_dump_var_event);
108 
109 
110 /*
111  * exported:
112  * expand the variable length event to linear buffer space.
113  */
114 
115 static int seq_copy_in_kernel(char **bufptr, const void *src, int size)
116 {
117 	memcpy(*bufptr, src, size);
118 	*bufptr += size;
119 	return 0;
120 }
121 
122 static int seq_copy_in_user(char __user **bufptr, const void *src, int size)
123 {
124 	if (copy_to_user(*bufptr, src, size))
125 		return -EFAULT;
126 	*bufptr += size;
127 	return 0;
128 }
129 
130 int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,
131 			     int in_kernel, int size_aligned)
132 {
133 	int len, newlen;
134 	int err;
135 
136 	if ((len = get_var_len(event)) < 0)
137 		return len;
138 	newlen = len;
139 	if (size_aligned > 0)
140 		newlen = roundup(len, size_aligned);
141 	if (count < newlen)
142 		return -EAGAIN;
143 
144 	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
145 		if (! in_kernel)
146 			return -EINVAL;
147 		if (copy_from_user(buf, (void __force __user *)event->data.ext.ptr, len))
148 			return -EFAULT;
149 		return newlen;
150 	}
151 	err = snd_seq_dump_var_event(event,
152 				     in_kernel ? (snd_seq_dump_func_t)seq_copy_in_kernel :
153 				     (snd_seq_dump_func_t)seq_copy_in_user,
154 				     &buf);
155 	return err < 0 ? err : newlen;
156 }
157 EXPORT_SYMBOL(snd_seq_expand_var_event);
158 
159 /*
160  * release this cell, free extended data if available
161  */
162 
163 static inline void free_cell(struct snd_seq_pool *pool,
164 			     struct snd_seq_event_cell *cell)
165 {
166 	cell->next = pool->free;
167 	pool->free = cell;
168 	atomic_dec(&pool->counter);
169 }
170 
171 void snd_seq_cell_free(struct snd_seq_event_cell * cell)
172 {
173 	unsigned long flags;
174 	struct snd_seq_pool *pool;
175 
176 	if (snd_BUG_ON(!cell))
177 		return;
178 	pool = cell->pool;
179 	if (snd_BUG_ON(!pool))
180 		return;
181 
182 	spin_lock_irqsave(&pool->lock, flags);
183 	free_cell(pool, cell);
184 	if (snd_seq_ev_is_variable(&cell->event)) {
185 		if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) {
186 			struct snd_seq_event_cell *curp, *nextptr;
187 			curp = cell->event.data.ext.ptr;
188 			for (; curp; curp = nextptr) {
189 				nextptr = curp->next;
190 				curp->next = pool->free;
191 				free_cell(pool, curp);
192 			}
193 		}
194 	}
195 	if (waitqueue_active(&pool->output_sleep)) {
196 		/* has enough space now? */
197 		if (snd_seq_output_ok(pool))
198 			wake_up(&pool->output_sleep);
199 	}
200 	spin_unlock_irqrestore(&pool->lock, flags);
201 }
202 
203 
204 /*
205  * allocate an event cell.
206  */
207 static int snd_seq_cell_alloc(struct snd_seq_pool *pool,
208 			      struct snd_seq_event_cell **cellp,
209 			      int nonblock, struct file *file,
210 			      struct mutex *mutexp)
211 {
212 	struct snd_seq_event_cell *cell;
213 	unsigned long flags;
214 	int err = -EAGAIN;
215 	wait_queue_entry_t wait;
216 
217 	if (pool == NULL)
218 		return -EINVAL;
219 
220 	*cellp = NULL;
221 
222 	init_waitqueue_entry(&wait, current);
223 	spin_lock_irqsave(&pool->lock, flags);
224 	if (pool->ptr == NULL) {	/* not initialized */
225 		pr_debug("ALSA: seq: pool is not initialized\n");
226 		err = -EINVAL;
227 		goto __error;
228 	}
229 	while (pool->free == NULL && ! nonblock && ! pool->closing) {
230 
231 		set_current_state(TASK_INTERRUPTIBLE);
232 		add_wait_queue(&pool->output_sleep, &wait);
233 		spin_unlock_irqrestore(&pool->lock, flags);
234 		if (mutexp)
235 			mutex_unlock(mutexp);
236 		schedule();
237 		if (mutexp)
238 			mutex_lock(mutexp);
239 		spin_lock_irqsave(&pool->lock, flags);
240 		remove_wait_queue(&pool->output_sleep, &wait);
241 		/* interrupted? */
242 		if (signal_pending(current)) {
243 			err = -ERESTARTSYS;
244 			goto __error;
245 		}
246 	}
247 	if (pool->closing) { /* closing.. */
248 		err = -ENOMEM;
249 		goto __error;
250 	}
251 
252 	cell = pool->free;
253 	if (cell) {
254 		int used;
255 		pool->free = cell->next;
256 		atomic_inc(&pool->counter);
257 		used = atomic_read(&pool->counter);
258 		if (pool->max_used < used)
259 			pool->max_used = used;
260 		pool->event_alloc_success++;
261 		/* clear cell pointers */
262 		cell->next = NULL;
263 		err = 0;
264 	} else
265 		pool->event_alloc_failures++;
266 	*cellp = cell;
267 
268 __error:
269 	spin_unlock_irqrestore(&pool->lock, flags);
270 	return err;
271 }
272 
273 
274 /*
275  * duplicate the event to a cell.
276  * if the event has external data, the data is decomposed to additional
277  * cells.
278  */
279 int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,
280 		      struct snd_seq_event_cell **cellp, int nonblock,
281 		      struct file *file, struct mutex *mutexp)
282 {
283 	int ncells, err;
284 	unsigned int extlen;
285 	struct snd_seq_event_cell *cell;
286 
287 	*cellp = NULL;
288 
289 	ncells = 0;
290 	extlen = 0;
291 	if (snd_seq_ev_is_variable(event)) {
292 		extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
293 		ncells = (extlen + sizeof(struct snd_seq_event) - 1) / sizeof(struct snd_seq_event);
294 	}
295 	if (ncells >= pool->total_elements)
296 		return -ENOMEM;
297 
298 	err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp);
299 	if (err < 0)
300 		return err;
301 
302 	/* copy the event */
303 	cell->event = *event;
304 
305 	/* decompose */
306 	if (snd_seq_ev_is_variable(event)) {
307 		int len = extlen;
308 		int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED;
309 		int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR;
310 		struct snd_seq_event_cell *src, *tmp, *tail;
311 		char *buf;
312 
313 		cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED;
314 		cell->event.data.ext.ptr = NULL;
315 
316 		src = (struct snd_seq_event_cell *)event->data.ext.ptr;
317 		buf = (char *)event->data.ext.ptr;
318 		tail = NULL;
319 
320 		while (ncells-- > 0) {
321 			int size = sizeof(struct snd_seq_event);
322 			if (len < size)
323 				size = len;
324 			err = snd_seq_cell_alloc(pool, &tmp, nonblock, file,
325 						 mutexp);
326 			if (err < 0)
327 				goto __error;
328 			if (cell->event.data.ext.ptr == NULL)
329 				cell->event.data.ext.ptr = tmp;
330 			if (tail)
331 				tail->next = tmp;
332 			tail = tmp;
333 			/* copy chunk */
334 			if (is_chained && src) {
335 				tmp->event = src->event;
336 				src = src->next;
337 			} else if (is_usrptr) {
338 				if (copy_from_user(&tmp->event, (char __force __user *)buf, size)) {
339 					err = -EFAULT;
340 					goto __error;
341 				}
342 			} else {
343 				memcpy(&tmp->event, buf, size);
344 			}
345 			buf += size;
346 			len -= size;
347 		}
348 	}
349 
350 	*cellp = cell;
351 	return 0;
352 
353 __error:
354 	snd_seq_cell_free(cell);
355 	return err;
356 }
357 
358 
359 /* poll wait */
360 int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file,
361 			   poll_table *wait)
362 {
363 	poll_wait(file, &pool->output_sleep, wait);
364 	return snd_seq_output_ok(pool);
365 }
366 
367 
368 /* allocate room specified number of events */
369 int snd_seq_pool_init(struct snd_seq_pool *pool)
370 {
371 	int cell;
372 	struct snd_seq_event_cell *cellptr;
373 
374 	if (snd_BUG_ON(!pool))
375 		return -EINVAL;
376 
377 	cellptr = kvmalloc_array(sizeof(struct snd_seq_event_cell), pool->size,
378 				 GFP_KERNEL);
379 	if (!cellptr)
380 		return -ENOMEM;
381 
382 	/* add new cells to the free cell list */
383 	spin_lock_irq(&pool->lock);
384 	if (pool->ptr) {
385 		spin_unlock_irq(&pool->lock);
386 		kvfree(cellptr);
387 		return 0;
388 	}
389 
390 	pool->ptr = cellptr;
391 	pool->free = NULL;
392 
393 	for (cell = 0; cell < pool->size; cell++) {
394 		cellptr = pool->ptr + cell;
395 		cellptr->pool = pool;
396 		cellptr->next = pool->free;
397 		pool->free = cellptr;
398 	}
399 	pool->room = (pool->size + 1) / 2;
400 
401 	/* init statistics */
402 	pool->max_used = 0;
403 	pool->total_elements = pool->size;
404 	spin_unlock_irq(&pool->lock);
405 	return 0;
406 }
407 
408 /* refuse the further insertion to the pool */
409 void snd_seq_pool_mark_closing(struct snd_seq_pool *pool)
410 {
411 	unsigned long flags;
412 
413 	if (snd_BUG_ON(!pool))
414 		return;
415 	spin_lock_irqsave(&pool->lock, flags);
416 	pool->closing = 1;
417 	spin_unlock_irqrestore(&pool->lock, flags);
418 }
419 
420 /* remove events */
421 int snd_seq_pool_done(struct snd_seq_pool *pool)
422 {
423 	struct snd_seq_event_cell *ptr;
424 
425 	if (snd_BUG_ON(!pool))
426 		return -EINVAL;
427 
428 	/* wait for closing all threads */
429 	if (waitqueue_active(&pool->output_sleep))
430 		wake_up(&pool->output_sleep);
431 
432 	while (atomic_read(&pool->counter) > 0)
433 		schedule_timeout_uninterruptible(1);
434 
435 	/* release all resources */
436 	spin_lock_irq(&pool->lock);
437 	ptr = pool->ptr;
438 	pool->ptr = NULL;
439 	pool->free = NULL;
440 	pool->total_elements = 0;
441 	spin_unlock_irq(&pool->lock);
442 
443 	kvfree(ptr);
444 
445 	spin_lock_irq(&pool->lock);
446 	pool->closing = 0;
447 	spin_unlock_irq(&pool->lock);
448 
449 	return 0;
450 }
451 
452 
453 /* init new memory pool */
454 struct snd_seq_pool *snd_seq_pool_new(int poolsize)
455 {
456 	struct snd_seq_pool *pool;
457 
458 	/* create pool block */
459 	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
460 	if (!pool)
461 		return NULL;
462 	spin_lock_init(&pool->lock);
463 	pool->ptr = NULL;
464 	pool->free = NULL;
465 	pool->total_elements = 0;
466 	atomic_set(&pool->counter, 0);
467 	pool->closing = 0;
468 	init_waitqueue_head(&pool->output_sleep);
469 
470 	pool->size = poolsize;
471 
472 	/* init statistics */
473 	pool->max_used = 0;
474 	return pool;
475 }
476 
477 /* remove memory pool */
478 int snd_seq_pool_delete(struct snd_seq_pool **ppool)
479 {
480 	struct snd_seq_pool *pool = *ppool;
481 
482 	*ppool = NULL;
483 	if (pool == NULL)
484 		return 0;
485 	snd_seq_pool_mark_closing(pool);
486 	snd_seq_pool_done(pool);
487 	kfree(pool);
488 	return 0;
489 }
490 
491 /* exported to seq_clientmgr.c */
492 void snd_seq_info_pool(struct snd_info_buffer *buffer,
493 		       struct snd_seq_pool *pool, char *space)
494 {
495 	if (pool == NULL)
496 		return;
497 	snd_iprintf(buffer, "%sPool size          : %d\n", space, pool->total_elements);
498 	snd_iprintf(buffer, "%sCells in use       : %d\n", space, atomic_read(&pool->counter));
499 	snd_iprintf(buffer, "%sPeak cells in use  : %d\n", space, pool->max_used);
500 	snd_iprintf(buffer, "%sAlloc success      : %d\n", space, pool->event_alloc_success);
501 	snd_iprintf(buffer, "%sAlloc failures     : %d\n", space, pool->event_alloc_failures);
502 }
503