xref: /linux/sound/core/seq/seq_memory.c (revision 2da68a77) 
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 	len = get_var_len(event);
73 	if (len <= 0)
74 		return len;
75 
76 	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
77 		char buf[32];
78 		char __user *curptr = (char __force __user *)event->data.ext.ptr;
79 		while (len > 0) {
80 			int size = sizeof(buf);
81 			if (len < size)
82 				size = len;
83 			if (copy_from_user(buf, curptr, size))
84 				return -EFAULT;
85 			err = func(private_data, buf, size);
86 			if (err < 0)
87 				return err;
88 			curptr += size;
89 			len -= size;
90 		}
91 		return 0;
92 	}
93 	if (!(event->data.ext.len & SNDRV_SEQ_EXT_CHAINED))
94 		return func(private_data, event->data.ext.ptr, len);
95 
96 	cell = (struct snd_seq_event_cell *)event->data.ext.ptr;
97 	for (; len > 0 && cell; cell = cell->next) {
98 		int size = sizeof(struct snd_seq_event);
99 		if (len < size)
100 			size = len;
101 		err = func(private_data, &cell->event, size);
102 		if (err < 0)
103 			return err;
104 		len -= size;
105 	}
106 	return 0;
107 }
108 EXPORT_SYMBOL(snd_seq_dump_var_event);
109 
110 
111 /*
112  * exported:
113  * expand the variable length event to linear buffer space.
114  */
115 
116 static int seq_copy_in_kernel(void *ptr, void *src, int size)
117 {
118 	char **bufptr = ptr;
119 
120 	memcpy(*bufptr, src, size);
121 	*bufptr += size;
122 	return 0;
123 }
124 
125 static int seq_copy_in_user(void *ptr, void *src, int size)
126 {
127 	char __user **bufptr = ptr;
128 
129 	if (copy_to_user(*bufptr, src, size))
130 		return -EFAULT;
131 	*bufptr += size;
132 	return 0;
133 }
134 
135 int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,
136 			     int in_kernel, int size_aligned)
137 {
138 	int len, newlen;
139 	int err;
140 
141 	len = get_var_len(event);
142 	if (len < 0)
143 		return len;
144 	newlen = len;
145 	if (size_aligned > 0)
146 		newlen = roundup(len, size_aligned);
147 	if (count < newlen)
148 		return -EAGAIN;
149 
150 	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
151 		if (! in_kernel)
152 			return -EINVAL;
153 		if (copy_from_user(buf, (void __force __user *)event->data.ext.ptr, len))
154 			return -EFAULT;
155 		return newlen;
156 	}
157 	err = snd_seq_dump_var_event(event,
158 				     in_kernel ? seq_copy_in_kernel : seq_copy_in_user,
159 				     &buf);
160 	return err < 0 ? err : newlen;
161 }
162 EXPORT_SYMBOL(snd_seq_expand_var_event);
163 
164 /*
165  * release this cell, free extended data if available
166  */
167 
168 static inline void free_cell(struct snd_seq_pool *pool,
169 			     struct snd_seq_event_cell *cell)
170 {
171 	cell->next = pool->free;
172 	pool->free = cell;
173 	atomic_dec(&pool->counter);
174 }
175 
176 void snd_seq_cell_free(struct snd_seq_event_cell * cell)
177 {
178 	unsigned long flags;
179 	struct snd_seq_pool *pool;
180 
181 	if (snd_BUG_ON(!cell))
182 		return;
183 	pool = cell->pool;
184 	if (snd_BUG_ON(!pool))
185 		return;
186 
187 	spin_lock_irqsave(&pool->lock, flags);
188 	free_cell(pool, cell);
189 	if (snd_seq_ev_is_variable(&cell->event)) {
190 		if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) {
191 			struct snd_seq_event_cell *curp, *nextptr;
192 			curp = cell->event.data.ext.ptr;
193 			for (; curp; curp = nextptr) {
194 				nextptr = curp->next;
195 				curp->next = pool->free;
196 				free_cell(pool, curp);
197 			}
198 		}
199 	}
200 	if (waitqueue_active(&pool->output_sleep)) {
201 		/* has enough space now? */
202 		if (snd_seq_output_ok(pool))
203 			wake_up(&pool->output_sleep);
204 	}
205 	spin_unlock_irqrestore(&pool->lock, flags);
206 }
207 
208 
209 /*
210  * allocate an event cell.
211  */
212 static int snd_seq_cell_alloc(struct snd_seq_pool *pool,
213 			      struct snd_seq_event_cell **cellp,
214 			      int nonblock, struct file *file,
215 			      struct mutex *mutexp)
216 {
217 	struct snd_seq_event_cell *cell;
218 	unsigned long flags;
219 	int err = -EAGAIN;
220 	wait_queue_entry_t wait;
221 
222 	if (pool == NULL)
223 		return -EINVAL;
224 
225 	*cellp = NULL;
226 
227 	init_waitqueue_entry(&wait, current);
228 	spin_lock_irqsave(&pool->lock, flags);
229 	if (pool->ptr == NULL) {	/* not initialized */
230 		pr_debug("ALSA: seq: pool is not initialized\n");
231 		err = -EINVAL;
232 		goto __error;
233 	}
234 	while (pool->free == NULL && ! nonblock && ! pool->closing) {
235 
236 		set_current_state(TASK_INTERRUPTIBLE);
237 		add_wait_queue(&pool->output_sleep, &wait);
238 		spin_unlock_irqrestore(&pool->lock, flags);
239 		if (mutexp)
240 			mutex_unlock(mutexp);
241 		schedule();
242 		if (mutexp)
243 			mutex_lock(mutexp);
244 		spin_lock_irqsave(&pool->lock, flags);
245 		remove_wait_queue(&pool->output_sleep, &wait);
246 		/* interrupted? */
247 		if (signal_pending(current)) {
248 			err = -ERESTARTSYS;
249 			goto __error;
250 		}
251 	}
252 	if (pool->closing) { /* closing.. */
253 		err = -ENOMEM;
254 		goto __error;
255 	}
256 
257 	cell = pool->free;
258 	if (cell) {
259 		int used;
260 		pool->free = cell->next;
261 		atomic_inc(&pool->counter);
262 		used = atomic_read(&pool->counter);
263 		if (pool->max_used < used)
264 			pool->max_used = used;
265 		pool->event_alloc_success++;
266 		/* clear cell pointers */
267 		cell->next = NULL;
268 		err = 0;
269 	} else
270 		pool->event_alloc_failures++;
271 	*cellp = cell;
272 
273 __error:
274 	spin_unlock_irqrestore(&pool->lock, flags);
275 	return err;
276 }
277 
278 
279 /*
280  * duplicate the event to a cell.
281  * if the event has external data, the data is decomposed to additional
282  * cells.
283  */
284 int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,
285 		      struct snd_seq_event_cell **cellp, int nonblock,
286 		      struct file *file, struct mutex *mutexp)
287 {
288 	int ncells, err;
289 	unsigned int extlen;
290 	struct snd_seq_event_cell *cell;
291 
292 	*cellp = NULL;
293 
294 	ncells = 0;
295 	extlen = 0;
296 	if (snd_seq_ev_is_variable(event)) {
297 		extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
298 		ncells = DIV_ROUND_UP(extlen, sizeof(struct snd_seq_event));
299 	}
300 	if (ncells >= pool->total_elements)
301 		return -ENOMEM;
302 
303 	err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp);
304 	if (err < 0)
305 		return err;
306 
307 	/* copy the event */
308 	cell->event = *event;
309 
310 	/* decompose */
311 	if (snd_seq_ev_is_variable(event)) {
312 		int len = extlen;
313 		int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED;
314 		int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR;
315 		struct snd_seq_event_cell *src, *tmp, *tail;
316 		char *buf;
317 
318 		cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED;
319 		cell->event.data.ext.ptr = NULL;
320 
321 		src = (struct snd_seq_event_cell *)event->data.ext.ptr;
322 		buf = (char *)event->data.ext.ptr;
323 		tail = NULL;
324 
325 		while (ncells-- > 0) {
326 			int size = sizeof(struct snd_seq_event);
327 			if (len < size)
328 				size = len;
329 			err = snd_seq_cell_alloc(pool, &tmp, nonblock, file,
330 						 mutexp);
331 			if (err < 0)
332 				goto __error;
333 			if (cell->event.data.ext.ptr == NULL)
334 				cell->event.data.ext.ptr = tmp;
335 			if (tail)
336 				tail->next = tmp;
337 			tail = tmp;
338 			/* copy chunk */
339 			if (is_chained && src) {
340 				tmp->event = src->event;
341 				src = src->next;
342 			} else if (is_usrptr) {
343 				if (copy_from_user(&tmp->event, (char __force __user *)buf, size)) {
344 					err = -EFAULT;
345 					goto __error;
346 				}
347 			} else {
348 				memcpy(&tmp->event, buf, size);
349 			}
350 			buf += size;
351 			len -= size;
352 		}
353 	}
354 
355 	*cellp = cell;
356 	return 0;
357 
358 __error:
359 	snd_seq_cell_free(cell);
360 	return err;
361 }
362 
363 
364 /* poll wait */
365 int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file,
366 			   poll_table *wait)
367 {
368 	poll_wait(file, &pool->output_sleep, wait);
369 	return snd_seq_output_ok(pool);
370 }
371 
372 
373 /* allocate room specified number of events */
374 int snd_seq_pool_init(struct snd_seq_pool *pool)
375 {
376 	int cell;
377 	struct snd_seq_event_cell *cellptr;
378 
379 	if (snd_BUG_ON(!pool))
380 		return -EINVAL;
381 
382 	cellptr = kvmalloc_array(sizeof(struct snd_seq_event_cell), pool->size,
383 				 GFP_KERNEL);
384 	if (!cellptr)
385 		return -ENOMEM;
386 
387 	/* add new cells to the free cell list */
388 	spin_lock_irq(&pool->lock);
389 	if (pool->ptr) {
390 		spin_unlock_irq(&pool->lock);
391 		kvfree(cellptr);
392 		return 0;
393 	}
394 
395 	pool->ptr = cellptr;
396 	pool->free = NULL;
397 
398 	for (cell = 0; cell < pool->size; cell++) {
399 		cellptr = pool->ptr + cell;
400 		cellptr->pool = pool;
401 		cellptr->next = pool->free;
402 		pool->free = cellptr;
403 	}
404 	pool->room = (pool->size + 1) / 2;
405 
406 	/* init statistics */
407 	pool->max_used = 0;
408 	pool->total_elements = pool->size;
409 	spin_unlock_irq(&pool->lock);
410 	return 0;
411 }
412 
413 /* refuse the further insertion to the pool */
414 void snd_seq_pool_mark_closing(struct snd_seq_pool *pool)
415 {
416 	unsigned long flags;
417 
418 	if (snd_BUG_ON(!pool))
419 		return;
420 	spin_lock_irqsave(&pool->lock, flags);
421 	pool->closing = 1;
422 	spin_unlock_irqrestore(&pool->lock, flags);
423 }
424 
425 /* remove events */
426 int snd_seq_pool_done(struct snd_seq_pool *pool)
427 {
428 	struct snd_seq_event_cell *ptr;
429 
430 	if (snd_BUG_ON(!pool))
431 		return -EINVAL;
432 
433 	/* wait for closing all threads */
434 	if (waitqueue_active(&pool->output_sleep))
435 		wake_up(&pool->output_sleep);
436 
437 	while (atomic_read(&pool->counter) > 0)
438 		schedule_timeout_uninterruptible(1);
439 
440 	/* release all resources */
441 	spin_lock_irq(&pool->lock);
442 	ptr = pool->ptr;
443 	pool->ptr = NULL;
444 	pool->free = NULL;
445 	pool->total_elements = 0;
446 	spin_unlock_irq(&pool->lock);
447 
448 	kvfree(ptr);
449 
450 	spin_lock_irq(&pool->lock);
451 	pool->closing = 0;
452 	spin_unlock_irq(&pool->lock);
453 
454 	return 0;
455 }
456 
457 
458 /* init new memory pool */
459 struct snd_seq_pool *snd_seq_pool_new(int poolsize)
460 {
461 	struct snd_seq_pool *pool;
462 
463 	/* create pool block */
464 	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
465 	if (!pool)
466 		return NULL;
467 	spin_lock_init(&pool->lock);
468 	pool->ptr = NULL;
469 	pool->free = NULL;
470 	pool->total_elements = 0;
471 	atomic_set(&pool->counter, 0);
472 	pool->closing = 0;
473 	init_waitqueue_head(&pool->output_sleep);
474 
475 	pool->size = poolsize;
476 
477 	/* init statistics */
478 	pool->max_used = 0;
479 	return pool;
480 }
481 
482 /* remove memory pool */
483 int snd_seq_pool_delete(struct snd_seq_pool **ppool)
484 {
485 	struct snd_seq_pool *pool = *ppool;
486 
487 	*ppool = NULL;
488 	if (pool == NULL)
489 		return 0;
490 	snd_seq_pool_mark_closing(pool);
491 	snd_seq_pool_done(pool);
492 	kfree(pool);
493 	return 0;
494 }
495 
496 /* exported to seq_clientmgr.c */
497 void snd_seq_info_pool(struct snd_info_buffer *buffer,
498 		       struct snd_seq_pool *pool, char *space)
499 {
500 	if (pool == NULL)
501 		return;
502 	snd_iprintf(buffer, "%sPool size          : %d\n", space, pool->total_elements);
503 	snd_iprintf(buffer, "%sCells in use       : %d\n", space, atomic_read(&pool->counter));
504 	snd_iprintf(buffer, "%sPeak cells in use  : %d\n", space, pool->max_used);
505 	snd_iprintf(buffer, "%sAlloc success      : %d\n", space, pool->event_alloc_success);
506 	snd_iprintf(buffer, "%sAlloc failures     : %d\n", space, pool->event_alloc_failures);
507 }
508