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(v: &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(to: buf, from: curptr, n: 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, offset: 0, maxlen: 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(to: *bufptr, from: src, n: 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(to: buf,
164 from: (char __force __user *)event->data.ext.ptr + offset,
165 n: size))
166 return -EFAULT;
167 return 0;
168 }
169 return dump_var_event(event,
170 func: in_kernel ? seq_copy_in_kernel : seq_copy_in_user,
171 private_data: &buf, offset, maxlen: 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, offset: 0, size: 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(to: (__force void __user *)buf + len,
194 n: 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, size: count, buf, in_kernel: 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(v: &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)(l: &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, cell: curp);
253 }
254 }
255 }
256 if (waitqueue_active(wq_head: &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(wq_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(wq_head: &pool->output_sleep, wq_entry: &wait);
293 spin_unlock_irqrestore(lock: &pool->lock, flags);
294 if (mutexp)
295 mutex_unlock(lock: mutexp);
296 schedule();
297 if (mutexp)
298 mutex_lock(mutexp);
299 spin_lock_irqsave(&pool->lock, flags);
300 remove_wait_queue(wq_head: &pool->output_sleep, wq_entry: &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(v: &pool->counter);
317 used = atomic_read(v: &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(lock: &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, cellp: &cell, nonblock, file, mutexp);
360 if (err < 0)
361 return err;
362
363 /* copy the event */
364 size = snd_seq_event_packet_size(ev: 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, cellp: &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(to: &tmp->event, from: (char __force __user *)buf, n: 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(filp: file, wait_address: &pool->output_sleep, p: wait);
430 guard(spinlock_irq)(l: &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)(l: &pool->lock);
452 if (pool->ptr) {
453 kvfree(addr: 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)(l: &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(wq_head: &pool->output_sleep))
493 wake_up(&pool->output_sleep);
494
495 while (atomic_read(v: &pool->counter) > 0)
496 schedule_timeout_uninterruptible(timeout: 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(addr: ptr);
507
508 guard(spinlock_irq)(l: &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(v: &pool->counter, i: 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(objp: 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}
565

source code of linux/sound/core/seq/seq_memory.c