seq_memory.c

  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
 22static inline int snd_seq_pool_available(struct snd_seq_pool *pool)
 23{
 24	return pool->total_elements - atomic_read(&pool->counter);
 25}
 26
 27static 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
 58static 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
 66static int dump_var_event(const struct snd_seq_event *event,
 67			  snd_seq_dump_func_t func, void *private_data,
 68			  int offset, int maxlen)
 69{
 70	int len, err;
 71	struct snd_seq_event_cell *cell;
 72
 73	len = get_var_len(event);
 74	if (len <= 0)
 75		return len;
 76	if (len <= offset)
 77		return 0;
 78	if (maxlen && len > offset + maxlen)
 79		len = offset + maxlen;
 80
 81	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
 82		char buf[32];
 83		char __user *curptr = (char __force __user *)event->data.ext.ptr;
 84		curptr += offset;
 85		len -= offset;
 86		while (len > 0) {
 87			int size = sizeof(buf);
 88			if (len < size)
 89				size = len;
 90			if (copy_from_user(buf, curptr, size))
 91				return -EFAULT;
 92			err = func(private_data, buf, size);
 93			if (err < 0)
 94				return err;
 95			curptr += size;
 96			len -= size;
 97		}
 98		return 0;
 99	}
100	if (!(event->data.ext.len & SNDRV_SEQ_EXT_CHAINED))
101		return func(private_data, event->data.ext.ptr + offset,
102			    len - offset);
103
104	cell = (struct snd_seq_event_cell *)event->data.ext.ptr;
105	for (; len > 0 && cell; cell = cell->next) {
106		int size = sizeof(struct snd_seq_event);
107		char *curptr = (char *)&cell->event;
108
109		if (offset >= size) {
110			offset -= size;
111			len -= size;
112			continue;
113		}
114		if (len < size)
115			size = len;
116		err = func(private_data, curptr + offset, size - offset);
117		if (err < 0)
118			return err;
119		offset = 0;
120		len -= size;
121	}
122	return 0;
123}
124
125int snd_seq_dump_var_event(const struct snd_seq_event *event,
126			   snd_seq_dump_func_t func, void *private_data)
127{
128	return dump_var_event(event, func, private_data, 0, 0);
129}
130EXPORT_SYMBOL(snd_seq_dump_var_event);
131
132
133/*
134 * exported:
135 * expand the variable length event to linear buffer space.
136 */
137
138static int seq_copy_in_kernel(void *ptr, void *src, int size)
139{
140	char **bufptr = ptr;
141
142	memcpy(*bufptr, src, size);
143	*bufptr += size;
144	return 0;
145}
146
147static int seq_copy_in_user(void *ptr, void *src, int size)
148{
149	char __user **bufptr = ptr;
150
151	if (copy_to_user(*bufptr, src, size))
152		return -EFAULT;
153	*bufptr += size;
154	return 0;
155}
156
157static int expand_var_event(const struct snd_seq_event *event,
158			    int offset, int size, char *buf, bool in_kernel)
159{
160	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
161		if (! in_kernel)
162			return -EINVAL;
163		if (copy_from_user(buf,
164				   (char __force __user *)event->data.ext.ptr + offset,
165				   size))
166			return -EFAULT;
167		return 0;
168	}
169	return dump_var_event(event,
170			     in_kernel ? seq_copy_in_kernel : seq_copy_in_user,
171			     &buf, offset, size);
172}
173
174int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,
175			     int in_kernel, int size_aligned)
176{
177	int len, newlen, err;
178
179	len = get_var_len(event);
180	if (len < 0)
181		return len;
182	newlen = len;
183	if (size_aligned > 0)
184		newlen = roundup(len, size_aligned);
185	if (count < newlen)
186		return -EAGAIN;
187	err = expand_var_event(event, 0, len, buf, in_kernel);
188	if (err < 0)
189		return err;
190	if (len != newlen) {
191		if (in_kernel)
192			memset(buf + len, 0, newlen - len);
193		else if (clear_user((__force void __user *)buf + len,
194				    newlen - len))
195			return -EFAULT;
196	}
197	return newlen;
198}
199EXPORT_SYMBOL(snd_seq_expand_var_event);
200
201int snd_seq_expand_var_event_at(const struct snd_seq_event *event, int count,
202				char *buf, int offset)
203{
204	int len, err;
205
206	len = get_var_len(event);
207	if (len < 0)
208		return len;
209	if (len <= offset)
210		return 0;
211	len -= offset;
212	if (len > count)
213		len = count;
214	err = expand_var_event(event, offset, count, buf, true);
215	if (err < 0)
216		return err;
217	return len;
218}
219EXPORT_SYMBOL_GPL(snd_seq_expand_var_event_at);
220
221/*
222 * release this cell, free extended data if available
223 */
224
225static inline void free_cell(struct snd_seq_pool *pool,
226			     struct snd_seq_event_cell *cell)
227{
228	cell->next = pool->free;
229	pool->free = cell;
230	atomic_dec(&pool->counter);
231}
232
233void snd_seq_cell_free(struct snd_seq_event_cell * cell)
234{
235	struct snd_seq_pool *pool;
236
237	if (snd_BUG_ON(!cell))
238		return;
239	pool = cell->pool;
240	if (snd_BUG_ON(!pool))
241		return;
242
243	guard(spinlock_irqsave)(&pool->lock);
244	free_cell(pool, cell);
245	if (snd_seq_ev_is_variable(&cell->event)) {
246		if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) {
247			struct snd_seq_event_cell *curp, *nextptr;
248			curp = cell->event.data.ext.ptr;
249			for (; curp; curp = nextptr) {
250				nextptr = curp->next;
251				curp->next = pool->free;
252				free_cell(pool, curp);
253			}
254		}
255	}
256	if (waitqueue_active(&pool->output_sleep)) {
257		/* has enough space now? */
258		if (snd_seq_output_ok(pool))
259			wake_up(&pool->output_sleep);
260	}
261}
262
263
264/*
265 * allocate an event cell.
266 */
267static int snd_seq_cell_alloc(struct snd_seq_pool *pool,
268			      struct snd_seq_event_cell **cellp,
269			      int nonblock, struct file *file,
270			      struct mutex *mutexp)
271{
272	struct snd_seq_event_cell *cell;
273	unsigned long flags;
274	int err = -EAGAIN;
275	wait_queue_entry_t wait;
276
277	if (pool == NULL)
278		return -EINVAL;
279
280	*cellp = NULL;
281
282	init_waitqueue_entry(&wait, current);
283	spin_lock_irqsave(&pool->lock, flags);
284	if (pool->ptr == NULL) {	/* not initialized */
285		pr_debug("ALSA: seq: pool is not initialized\n");
286		err = -EINVAL;
287		goto __error;
288	}
289	while (pool->free == NULL && ! nonblock && ! pool->closing) {
290
291		set_current_state(TASK_INTERRUPTIBLE);
292		add_wait_queue(&pool->output_sleep, &wait);
293		spin_unlock_irqrestore(&pool->lock, flags);
294		if (mutexp)
295			mutex_unlock(mutexp);
296		schedule();
297		if (mutexp)
298			mutex_lock(mutexp);
299		spin_lock_irqsave(&pool->lock, flags);
300		remove_wait_queue(&pool->output_sleep, &wait);
301		/* interrupted? */
302		if (signal_pending(current)) {
303			err = -ERESTARTSYS;
304			goto __error;
305		}
306	}
307	if (pool->closing) { /* closing.. */
308		err = -ENOMEM;
309		goto __error;
310	}
311
312	cell = pool->free;
313	if (cell) {
314		int used;
315		pool->free = cell->next;
316		atomic_inc(&pool->counter);
317		used = atomic_read(&pool->counter);
318		if (pool->max_used < used)
319			pool->max_used = used;
320		pool->event_alloc_success++;
321		/* clear cell pointers */
322		cell->next = NULL;
323		err = 0;
324	} else
325		pool->event_alloc_failures++;
326	*cellp = cell;
327
328__error:
329	spin_unlock_irqrestore(&pool->lock, flags);
330	return err;
331}
332
333
334/*
335 * duplicate the event to a cell.
336 * if the event has external data, the data is decomposed to additional
337 * cells.
338 */
339int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,
340		      struct snd_seq_event_cell **cellp, int nonblock,
341		      struct file *file, struct mutex *mutexp)
342{
343	int ncells, err;
344	unsigned int extlen;
345	struct snd_seq_event_cell *cell;
346	int size;
347
348	*cellp = NULL;
349
350	ncells = 0;
351	extlen = 0;
352	if (snd_seq_ev_is_variable(event)) {
353		extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
354		ncells = DIV_ROUND_UP(extlen, sizeof(struct snd_seq_event));
355	}
356	if (ncells >= pool->total_elements)
357		return -ENOMEM;
358
359	err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp);
360	if (err < 0)
361		return err;
362
363	/* copy the event */
364	size = snd_seq_event_packet_size(event);
365	memcpy(&cell->ump, event, size);
366#if IS_ENABLED(CONFIG_SND_SEQ_UMP)
367	if (size < sizeof(cell->event))
368		cell->ump.raw.extra = 0;
369#endif
370
371	/* decompose */
372	if (snd_seq_ev_is_variable(event)) {
373		int len = extlen;
374		int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED;
375		int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR;
376		struct snd_seq_event_cell *src, *tmp, *tail;
377		char *buf;
378
379		cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED;
380		cell->event.data.ext.ptr = NULL;
381
382		src = (struct snd_seq_event_cell *)event->data.ext.ptr;
383		buf = (char *)event->data.ext.ptr;
384		tail = NULL;
385
386		while (ncells-- > 0) {
387			size = sizeof(struct snd_seq_event);
388			if (len < size)
389				size = len;
390			err = snd_seq_cell_alloc(pool, &tmp, nonblock, file,
391						 mutexp);
392			if (err < 0)
393				goto __error;
394			if (cell->event.data.ext.ptr == NULL)
395				cell->event.data.ext.ptr = tmp;
396			if (tail)
397				tail->next = tmp;
398			tail = tmp;
399			/* copy chunk */
400			if (is_chained && src) {
401				tmp->event = src->event;
402				src = src->next;
403			} else if (is_usrptr) {
404				if (copy_from_user(&tmp->event, (char __force __user *)buf, size)) {
405					err = -EFAULT;
406					goto __error;
407				}
408			} else {
409				memcpy(&tmp->event, buf, size);
410			}
411			buf += size;
412			len -= size;
413		}
414	}
415
416	*cellp = cell;
417	return 0;
418
419__error:
420	snd_seq_cell_free(cell);
421	return err;
422}
423  
424
425/* poll wait */
426int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file,
427			   poll_table *wait)
428{
429	poll_wait(file, &pool->output_sleep, wait);
430	guard(spinlock_irq)(&pool->lock);
431	return snd_seq_output_ok(pool);
432}
433
434
435/* allocate room specified number of events */
436int snd_seq_pool_init(struct snd_seq_pool *pool)
437{
438	int cell;
439	struct snd_seq_event_cell *cellptr;
440
441	if (snd_BUG_ON(!pool))
442		return -EINVAL;
443
444	cellptr = kvmalloc_array(pool->size,
445				 sizeof(struct snd_seq_event_cell),
446				 GFP_KERNEL);
447	if (!cellptr)
448		return -ENOMEM;
449
450	/* add new cells to the free cell list */
451	guard(spinlock_irq)(&pool->lock);
452	if (pool->ptr) {
453		kvfree(cellptr);
454		return 0;
455	}
456
457	pool->ptr = cellptr;
458	pool->free = NULL;
459
460	for (cell = 0; cell < pool->size; cell++) {
461		cellptr = pool->ptr + cell;
462		cellptr->pool = pool;
463		cellptr->next = pool->free;
464		pool->free = cellptr;
465	}
466	pool->room = (pool->size + 1) / 2;
467
468	/* init statistics */
469	pool->max_used = 0;
470	pool->total_elements = pool->size;
471	return 0;
472}
473
474/* refuse the further insertion to the pool */
475void snd_seq_pool_mark_closing(struct snd_seq_pool *pool)
476{
477	if (snd_BUG_ON(!pool))
478		return;
479	guard(spinlock_irqsave)(&pool->lock);
480	pool->closing = 1;
481}
482
483/* remove events */
484int snd_seq_pool_done(struct snd_seq_pool *pool)
485{
486	struct snd_seq_event_cell *ptr;
487
488	if (snd_BUG_ON(!pool))
489		return -EINVAL;
490
491	/* wait for closing all threads */
492	if (waitqueue_active(&pool->output_sleep))
493		wake_up(&pool->output_sleep);
494
495	while (atomic_read(&pool->counter) > 0)
496		schedule_timeout_uninterruptible(1);
497	
498	/* release all resources */
499	scoped_guard(spinlock_irq, &pool->lock) {
500		ptr = pool->ptr;
501		pool->ptr = NULL;
502		pool->free = NULL;
503		pool->total_elements = 0;
504	}
505
506	kvfree(ptr);
507
508	guard(spinlock_irq)(&pool->lock);
509	pool->closing = 0;
510
511	return 0;
512}
513
514
515/* init new memory pool */
516struct snd_seq_pool *snd_seq_pool_new(int poolsize)
517{
518	struct snd_seq_pool *pool;
519
520	/* create pool block */
521	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
522	if (!pool)
523		return NULL;
524	spin_lock_init(&pool->lock);
525	pool->ptr = NULL;
526	pool->free = NULL;
527	pool->total_elements = 0;
528	atomic_set(&pool->counter, 0);
529	pool->closing = 0;
530	init_waitqueue_head(&pool->output_sleep);
531	
532	pool->size = poolsize;
533
534	/* init statistics */
535	pool->max_used = 0;
536	return pool;
537}
538
539/* remove memory pool */
540int snd_seq_pool_delete(struct snd_seq_pool **ppool)
541{
542	struct snd_seq_pool *pool = *ppool;
543
544	*ppool = NULL;
545	if (pool == NULL)
546		return 0;
547	snd_seq_pool_mark_closing(pool);
548	snd_seq_pool_done(pool);
549	kfree(pool);
550	return 0;
551}
552
553/* exported to seq_clientmgr.c */
554void snd_seq_info_pool(struct snd_info_buffer *buffer,
555		       struct snd_seq_pool *pool, char *space)
556{
557	if (pool == NULL)
558		return;
559	snd_iprintf(buffer, "%sPool size          : %d\n", space, pool->total_elements);
560	snd_iprintf(buffer, "%sCells in use       : %d\n", space, atomic_read(&pool->counter));
561	snd_iprintf(buffer, "%sPeak cells in use  : %d\n", space, pool->max_used);
562	snd_iprintf(buffer, "%sAlloc success      : %d\n", space, pool->event_alloc_success);
563	snd_iprintf(buffer, "%sAlloc failures     : %d\n", space, pool->event_alloc_failures);
564}