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 memset(buf + len, 0, newlen - len); 192 return newlen; 193 } 194 EXPORT_SYMBOL(snd_seq_expand_var_event); 195 196 int snd_seq_expand_var_event_at(const struct snd_seq_event *event, int count, 197 char *buf, int offset) 198 { 199 int len, err; 200 201 len = get_var_len(event); 202 if (len < 0) 203 return len; 204 if (len <= offset) 205 return 0; 206 len -= offset; 207 if (len > count) 208 len = count; 209 err = expand_var_event(event, offset, count, buf, true); 210 if (err < 0) 211 return err; 212 return len; 213 } 214 EXPORT_SYMBOL_GPL(snd_seq_expand_var_event_at); 215 216 /* 217 * release this cell, free extended data if available 218 */ 219 220 static inline void free_cell(struct snd_seq_pool *pool, 221 struct snd_seq_event_cell *cell) 222 { 223 cell->next = pool->free; 224 pool->free = cell; 225 atomic_dec(&pool->counter); 226 } 227 228 void snd_seq_cell_free(struct snd_seq_event_cell * cell) 229 { 230 unsigned long flags; 231 struct snd_seq_pool *pool; 232 233 if (snd_BUG_ON(!cell)) 234 return; 235 pool = cell->pool; 236 if (snd_BUG_ON(!pool)) 237 return; 238 239 spin_lock_irqsave(&pool->lock, flags); 240 free_cell(pool, cell); 241 if (snd_seq_ev_is_variable(&cell->event)) { 242 if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) { 243 struct snd_seq_event_cell *curp, *nextptr; 244 curp = cell->event.data.ext.ptr; 245 for (; curp; curp = nextptr) { 246 nextptr = curp->next; 247 curp->next = pool->free; 248 free_cell(pool, curp); 249 } 250 } 251 } 252 if (waitqueue_active(&pool->output_sleep)) { 253 /* has enough space now? */ 254 if (snd_seq_output_ok(pool)) 255 wake_up(&pool->output_sleep); 256 } 257 spin_unlock_irqrestore(&pool->lock, flags); 258 } 259 260 261 /* 262 * allocate an event cell. 263 */ 264 static int snd_seq_cell_alloc(struct snd_seq_pool *pool, 265 struct snd_seq_event_cell **cellp, 266 int nonblock, struct file *file, 267 struct mutex *mutexp) 268 { 269 struct snd_seq_event_cell *cell; 270 unsigned long flags; 271 int err = -EAGAIN; 272 wait_queue_entry_t wait; 273 274 if (pool == NULL) 275 return -EINVAL; 276 277 *cellp = NULL; 278 279 init_waitqueue_entry(&wait, current); 280 spin_lock_irqsave(&pool->lock, flags); 281 if (pool->ptr == NULL) { /* not initialized */ 282 pr_debug("ALSA: seq: pool is not initialized\n"); 283 err = -EINVAL; 284 goto __error; 285 } 286 while (pool->free == NULL && ! nonblock && ! pool->closing) { 287 288 set_current_state(TASK_INTERRUPTIBLE); 289 add_wait_queue(&pool->output_sleep, &wait); 290 spin_unlock_irqrestore(&pool->lock, flags); 291 if (mutexp) 292 mutex_unlock(mutexp); 293 schedule(); 294 if (mutexp) 295 mutex_lock(mutexp); 296 spin_lock_irqsave(&pool->lock, flags); 297 remove_wait_queue(&pool->output_sleep, &wait); 298 /* interrupted? */ 299 if (signal_pending(current)) { 300 err = -ERESTARTSYS; 301 goto __error; 302 } 303 } 304 if (pool->closing) { /* closing.. */ 305 err = -ENOMEM; 306 goto __error; 307 } 308 309 cell = pool->free; 310 if (cell) { 311 int used; 312 pool->free = cell->next; 313 atomic_inc(&pool->counter); 314 used = atomic_read(&pool->counter); 315 if (pool->max_used < used) 316 pool->max_used = used; 317 pool->event_alloc_success++; 318 /* clear cell pointers */ 319 cell->next = NULL; 320 err = 0; 321 } else 322 pool->event_alloc_failures++; 323 *cellp = cell; 324 325 __error: 326 spin_unlock_irqrestore(&pool->lock, flags); 327 return err; 328 } 329 330 331 /* 332 * duplicate the event to a cell. 333 * if the event has external data, the data is decomposed to additional 334 * cells. 335 */ 336 int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event, 337 struct snd_seq_event_cell **cellp, int nonblock, 338 struct file *file, struct mutex *mutexp) 339 { 340 int ncells, err; 341 unsigned int extlen; 342 struct snd_seq_event_cell *cell; 343 int size; 344 345 *cellp = NULL; 346 347 ncells = 0; 348 extlen = 0; 349 if (snd_seq_ev_is_variable(event)) { 350 extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK; 351 ncells = DIV_ROUND_UP(extlen, sizeof(struct snd_seq_event)); 352 } 353 if (ncells >= pool->total_elements) 354 return -ENOMEM; 355 356 err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp); 357 if (err < 0) 358 return err; 359 360 /* copy the event */ 361 size = snd_seq_event_packet_size(event); 362 memcpy(&cell->ump, event, size); 363 #if IS_ENABLED(CONFIG_SND_SEQ_UMP) 364 if (size < sizeof(cell->event)) 365 cell->ump.raw.extra = 0; 366 #endif 367 368 /* decompose */ 369 if (snd_seq_ev_is_variable(event)) { 370 int len = extlen; 371 int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED; 372 int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR; 373 struct snd_seq_event_cell *src, *tmp, *tail; 374 char *buf; 375 376 cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED; 377 cell->event.data.ext.ptr = NULL; 378 379 src = (struct snd_seq_event_cell *)event->data.ext.ptr; 380 buf = (char *)event->data.ext.ptr; 381 tail = NULL; 382 383 while (ncells-- > 0) { 384 size = sizeof(struct snd_seq_event); 385 if (len < size) 386 size = len; 387 err = snd_seq_cell_alloc(pool, &tmp, nonblock, file, 388 mutexp); 389 if (err < 0) 390 goto __error; 391 if (cell->event.data.ext.ptr == NULL) 392 cell->event.data.ext.ptr = tmp; 393 if (tail) 394 tail->next = tmp; 395 tail = tmp; 396 /* copy chunk */ 397 if (is_chained && src) { 398 tmp->event = src->event; 399 src = src->next; 400 } else if (is_usrptr) { 401 if (copy_from_user(&tmp->event, (char __force __user *)buf, size)) { 402 err = -EFAULT; 403 goto __error; 404 } 405 } else { 406 memcpy(&tmp->event, buf, size); 407 } 408 buf += size; 409 len -= size; 410 } 411 } 412 413 *cellp = cell; 414 return 0; 415 416 __error: 417 snd_seq_cell_free(cell); 418 return err; 419 } 420 421 422 /* poll wait */ 423 int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file, 424 poll_table *wait) 425 { 426 poll_wait(file, &pool->output_sleep, wait); 427 return snd_seq_output_ok(pool); 428 } 429 430 431 /* allocate room specified number of events */ 432 int snd_seq_pool_init(struct snd_seq_pool *pool) 433 { 434 int cell; 435 struct snd_seq_event_cell *cellptr; 436 437 if (snd_BUG_ON(!pool)) 438 return -EINVAL; 439 440 cellptr = kvmalloc_array(sizeof(struct snd_seq_event_cell), pool->size, 441 GFP_KERNEL); 442 if (!cellptr) 443 return -ENOMEM; 444 445 /* add new cells to the free cell list */ 446 spin_lock_irq(&pool->lock); 447 if (pool->ptr) { 448 spin_unlock_irq(&pool->lock); 449 kvfree(cellptr); 450 return 0; 451 } 452 453 pool->ptr = cellptr; 454 pool->free = NULL; 455 456 for (cell = 0; cell < pool->size; cell++) { 457 cellptr = pool->ptr + cell; 458 cellptr->pool = pool; 459 cellptr->next = pool->free; 460 pool->free = cellptr; 461 } 462 pool->room = (pool->size + 1) / 2; 463 464 /* init statistics */ 465 pool->max_used = 0; 466 pool->total_elements = pool->size; 467 spin_unlock_irq(&pool->lock); 468 return 0; 469 } 470 471 /* refuse the further insertion to the pool */ 472 void snd_seq_pool_mark_closing(struct snd_seq_pool *pool) 473 { 474 unsigned long flags; 475 476 if (snd_BUG_ON(!pool)) 477 return; 478 spin_lock_irqsave(&pool->lock, flags); 479 pool->closing = 1; 480 spin_unlock_irqrestore(&pool->lock, flags); 481 } 482 483 /* remove events */ 484 int 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 spin_lock_irq(&pool->lock); 500 ptr = pool->ptr; 501 pool->ptr = NULL; 502 pool->free = NULL; 503 pool->total_elements = 0; 504 spin_unlock_irq(&pool->lock); 505 506 kvfree(ptr); 507 508 spin_lock_irq(&pool->lock); 509 pool->closing = 0; 510 spin_unlock_irq(&pool->lock); 511 512 return 0; 513 } 514 515 516 /* init new memory pool */ 517 struct snd_seq_pool *snd_seq_pool_new(int poolsize) 518 { 519 struct snd_seq_pool *pool; 520 521 /* create pool block */ 522 pool = kzalloc(sizeof(*pool), GFP_KERNEL); 523 if (!pool) 524 return NULL; 525 spin_lock_init(&pool->lock); 526 pool->ptr = NULL; 527 pool->free = NULL; 528 pool->total_elements = 0; 529 atomic_set(&pool->counter, 0); 530 pool->closing = 0; 531 init_waitqueue_head(&pool->output_sleep); 532 533 pool->size = poolsize; 534 535 /* init statistics */ 536 pool->max_used = 0; 537 return pool; 538 } 539 540 /* remove memory pool */ 541 int snd_seq_pool_delete(struct snd_seq_pool **ppool) 542 { 543 struct snd_seq_pool *pool = *ppool; 544 545 *ppool = NULL; 546 if (pool == NULL) 547 return 0; 548 snd_seq_pool_mark_closing(pool); 549 snd_seq_pool_done(pool); 550 kfree(pool); 551 return 0; 552 } 553 554 /* exported to seq_clientmgr.c */ 555 void snd_seq_info_pool(struct snd_info_buffer *buffer, 556 struct snd_seq_pool *pool, char *space) 557 { 558 if (pool == NULL) 559 return; 560 snd_iprintf(buffer, "%sPool size : %d\n", space, pool->total_elements); 561 snd_iprintf(buffer, "%sCells in use : %d\n", space, atomic_read(&pool->counter)); 562 snd_iprintf(buffer, "%sPeak cells in use : %d\n", space, pool->max_used); 563 snd_iprintf(buffer, "%sAlloc success : %d\n", space, pool->event_alloc_success); 564 snd_iprintf(buffer, "%sAlloc failures : %d\n", space, pool->event_alloc_failures); 565 } 566