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 static 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 } 124 125 int 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 } 130 EXPORT_SYMBOL(snd_seq_dump_var_event); 131 132 133 /* 134 * exported: 135 * expand the variable length event to linear buffer space. 136 */ 137 138 static 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 } 146 147 static 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 } 156 157 static 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 } 173 174 int 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 } 199 EXPORT_SYMBOL(snd_seq_expand_var_event); 200 201 int 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 } 219 EXPORT_SYMBOL_GPL(snd_seq_expand_var_event_at); 220 221 /* 222 * release this cell, free extended data if available 223 */ 224 225 static 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 } 232 233 void 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 */ 267 static 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 */ 339 int 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 */ 426 int 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 return snd_seq_output_ok(pool); 431 } 432 433 434 /* allocate room specified number of events */ 435 int snd_seq_pool_init(struct snd_seq_pool *pool) 436 { 437 int cell; 438 struct snd_seq_event_cell *cellptr; 439 440 if (snd_BUG_ON(!pool)) 441 return -EINVAL; 442 443 cellptr = kvmalloc_array(pool->size, 444 sizeof(struct snd_seq_event_cell), 445 GFP_KERNEL); 446 if (!cellptr) 447 return -ENOMEM; 448 449 /* add new cells to the free cell list */ 450 guard(spinlock_irq)(&pool->lock); 451 if (pool->ptr) { 452 kvfree(cellptr); 453 return 0; 454 } 455 456 pool->ptr = cellptr; 457 pool->free = NULL; 458 459 for (cell = 0; cell < pool->size; cell++) { 460 cellptr = pool->ptr + cell; 461 cellptr->pool = pool; 462 cellptr->next = pool->free; 463 pool->free = cellptr; 464 } 465 pool->room = (pool->size + 1) / 2; 466 467 /* init statistics */ 468 pool->max_used = 0; 469 pool->total_elements = pool->size; 470 return 0; 471 } 472 473 /* refuse the further insertion to the pool */ 474 void snd_seq_pool_mark_closing(struct snd_seq_pool *pool) 475 { 476 if (snd_BUG_ON(!pool)) 477 return; 478 guard(spinlock_irqsave)(&pool->lock); 479 pool->closing = 1; 480 } 481 482 /* remove events */ 483 int snd_seq_pool_done(struct snd_seq_pool *pool) 484 { 485 struct snd_seq_event_cell *ptr; 486 487 if (snd_BUG_ON(!pool)) 488 return -EINVAL; 489 490 /* wait for closing all threads */ 491 if (waitqueue_active(&pool->output_sleep)) 492 wake_up(&pool->output_sleep); 493 494 while (atomic_read(&pool->counter) > 0) 495 schedule_timeout_uninterruptible(1); 496 497 /* release all resources */ 498 scoped_guard(spinlock_irq, &pool->lock) { 499 ptr = pool->ptr; 500 pool->ptr = NULL; 501 pool->free = NULL; 502 pool->total_elements = 0; 503 } 504 505 kvfree(ptr); 506 507 guard(spinlock_irq)(&pool->lock); 508 pool->closing = 0; 509 510 return 0; 511 } 512 513 514 /* init new memory pool */ 515 struct snd_seq_pool *snd_seq_pool_new(int poolsize) 516 { 517 struct snd_seq_pool *pool; 518 519 /* create pool block */ 520 pool = kzalloc(sizeof(*pool), GFP_KERNEL); 521 if (!pool) 522 return NULL; 523 spin_lock_init(&pool->lock); 524 pool->ptr = NULL; 525 pool->free = NULL; 526 pool->total_elements = 0; 527 atomic_set(&pool->counter, 0); 528 pool->closing = 0; 529 init_waitqueue_head(&pool->output_sleep); 530 531 pool->size = poolsize; 532 533 /* init statistics */ 534 pool->max_used = 0; 535 return pool; 536 } 537 538 /* remove memory pool */ 539 int snd_seq_pool_delete(struct snd_seq_pool **ppool) 540 { 541 struct snd_seq_pool *pool = *ppool; 542 543 *ppool = NULL; 544 if (pool == NULL) 545 return 0; 546 snd_seq_pool_mark_closing(pool); 547 snd_seq_pool_done(pool); 548 kfree(pool); 549 return 0; 550 } 551 552 /* exported to seq_clientmgr.c */ 553 void snd_seq_info_pool(struct snd_info_buffer *buffer, 554 struct snd_seq_pool *pool, char *space) 555 { 556 if (pool == NULL) 557 return; 558 snd_iprintf(buffer, "%sPool size : %d\n", space, pool->total_elements); 559 snd_iprintf(buffer, "%sCells in use : %d\n", space, atomic_read(&pool->counter)); 560 snd_iprintf(buffer, "%sPeak cells in use : %d\n", space, pool->max_used); 561 snd_iprintf(buffer, "%sAlloc success : %d\n", space, pool->event_alloc_success); 562 snd_iprintf(buffer, "%sAlloc failures : %d\n", space, pool->event_alloc_failures); 563 } 564