core/seq/seq_memory.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  ALSA sequencer Memory Manager
0004  *  Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
0005  *                        Jaroslav Kysela <perex@perex.cz>
0006  *                2000 by Takashi Iwai <tiwai@suse.de>
0007  */
0008
0009 #include <linux/init.h>
0010 #include <linux/export.h>
0011 #include <linux/slab.h>
0012 #include <linux/sched/signal.h>
0013 #include <linux/mm.h>
0014 #include <sound/core.h>
0015
0016 #include <sound/seq_kernel.h>
0017 #include "seq_memory.h"
0018 #include "seq_queue.h"
0019 #include "seq_info.h"
0020 #include "seq_lock.h"
0021
0022 static inline int snd_seq_pool_available(struct snd_seq_pool *pool)
0023 {
0024     return pool->total_elements - atomic_read(&pool->counter);
0025 }
0026
0027 static inline int snd_seq_output_ok(struct snd_seq_pool *pool)
0028 {
0029     return snd_seq_pool_available(pool) >= pool->room;
0030 }
0031
0032 /*
0033  * Variable length event:
0034  * The event like sysex uses variable length type.
0035  * The external data may be stored in three different formats.
0036  * 1) kernel space
0037  *    This is the normal case.
0038  *      ext.data.len = length
0039  *      ext.data.ptr = buffer pointer
0040  * 2) user space
0041  *    When an event is generated via read(), the external data is
0042  *    kept in user space until expanded.
0043  *      ext.data.len = length | SNDRV_SEQ_EXT_USRPTR
0044  *      ext.data.ptr = userspace pointer
0045  * 3) chained cells
0046  *    When the variable length event is enqueued (in prioq or fifo),
0047  *    the external data is decomposed to several cells.
0048  *      ext.data.len = length | SNDRV_SEQ_EXT_CHAINED
0049  *      ext.data.ptr = the additiona cell head
0050  *         -> cell.next -> cell.next -> ..
0051  */
0052
0053 /*
0054  * exported:
0055  * call dump function to expand external data.
0056  */
0057
0058 static int get_var_len(const struct snd_seq_event *event)
0059 {
0060     if ((event->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
0061         return -EINVAL;
0062
0063     return event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
0064 }
0065
0066 int snd_seq_dump_var_event(const struct snd_seq_event *event,
0067                snd_seq_dump_func_t func, void *private_data)
0068 {
0069     int len, err;
0070     struct snd_seq_event_cell *cell;
0071
0072     len = get_var_len(event);
0073     if (len <= 0)
0074         return len;
0075
0076     if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
0077         char buf[32];
0078         char __user *curptr = (char __force __user *)event->data.ext.ptr;
0079         while (len > 0) {
0080             int size = sizeof(buf);
0081             if (len < size)
0082                 size = len;
0083             if (copy_from_user(buf, curptr, size))
0084                 return -EFAULT;
0085             err = func(private_data, buf, size);
0086             if (err < 0)
0087                 return err;
0088             curptr += size;
0089             len -= size;
0090         }
0091         return 0;
0092     }
0093     if (!(event->data.ext.len & SNDRV_SEQ_EXT_CHAINED))
0094         return func(private_data, event->data.ext.ptr, len);
0095
0096     cell = (struct snd_seq_event_cell *)event->data.ext.ptr;
0097     for (; len > 0 && cell; cell = cell->next) {
0098         int size = sizeof(struct snd_seq_event);
0099         if (len < size)
0100             size = len;
0101         err = func(private_data, &cell->event, size);
0102         if (err < 0)
0103             return err;
0104         len -= size;
0105     }
0106     return 0;
0107 }
0108 EXPORT_SYMBOL(snd_seq_dump_var_event);
0109
0110
0111 /*
0112  * exported:
0113  * expand the variable length event to linear buffer space.
0114  */
0115
0116 static int seq_copy_in_kernel(char **bufptr, const void *src, int size)
0117 {
0118     memcpy(*bufptr, src, size);
0119     *bufptr += size;
0120     return 0;
0121 }
0122
0123 static int seq_copy_in_user(char __user **bufptr, const void *src, int size)
0124 {
0125     if (copy_to_user(*bufptr, src, size))
0126         return -EFAULT;
0127     *bufptr += size;
0128     return 0;
0129 }
0130
0131 int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,
0132                  int in_kernel, int size_aligned)
0133 {
0134     int len, newlen;
0135     int err;
0136
0137     len = get_var_len(event);
0138     if (len < 0)
0139         return len;
0140     newlen = len;
0141     if (size_aligned > 0)
0142         newlen = roundup(len, size_aligned);
0143     if (count < newlen)
0144         return -EAGAIN;
0145
0146     if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
0147         if (! in_kernel)
0148             return -EINVAL;
0149         if (copy_from_user(buf, (void __force __user *)event->data.ext.ptr, len))
0150             return -EFAULT;
0151         return newlen;
0152     }
0153     err = snd_seq_dump_var_event(event,
0154                      in_kernel ? (snd_seq_dump_func_t)seq_copy_in_kernel :
0155                      (snd_seq_dump_func_t)seq_copy_in_user,
0156                      &buf);
0157     return err < 0 ? err : newlen;
0158 }
0159 EXPORT_SYMBOL(snd_seq_expand_var_event);
0160
0161 /*
0162  * release this cell, free extended data if available
0163  */
0164
0165 static inline void free_cell(struct snd_seq_pool *pool,
0166                  struct snd_seq_event_cell *cell)
0167 {
0168     cell->next = pool->free;
0169     pool->free = cell;
0170     atomic_dec(&pool->counter);
0171 }
0172
0173 void snd_seq_cell_free(struct snd_seq_event_cell * cell)
0174 {
0175     unsigned long flags;
0176     struct snd_seq_pool *pool;
0177
0178     if (snd_BUG_ON(!cell))
0179         return;
0180     pool = cell->pool;
0181     if (snd_BUG_ON(!pool))
0182         return;
0183
0184     spin_lock_irqsave(&pool->lock, flags);
0185     free_cell(pool, cell);
0186     if (snd_seq_ev_is_variable(&cell->event)) {
0187         if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) {
0188             struct snd_seq_event_cell *curp, *nextptr;
0189             curp = cell->event.data.ext.ptr;
0190             for (; curp; curp = nextptr) {
0191                 nextptr = curp->next;
0192                 curp->next = pool->free;
0193                 free_cell(pool, curp);
0194             }
0195         }
0196     }
0197     if (waitqueue_active(&pool->output_sleep)) {
0198         /* has enough space now? */
0199         if (snd_seq_output_ok(pool))
0200             wake_up(&pool->output_sleep);
0201     }
0202     spin_unlock_irqrestore(&pool->lock, flags);
0203 }
0204
0205
0206 /*
0207  * allocate an event cell.
0208  */
0209 static int snd_seq_cell_alloc(struct snd_seq_pool *pool,
0210                   struct snd_seq_event_cell **cellp,
0211                   int nonblock, struct file *file,
0212                   struct mutex *mutexp)
0213 {
0214     struct snd_seq_event_cell *cell;
0215     unsigned long flags;
0216     int err = -EAGAIN;
0217     wait_queue_entry_t wait;
0218
0219     if (pool == NULL)
0220         return -EINVAL;
0221
0222     *cellp = NULL;
0223
0224     init_waitqueue_entry(&wait, current);
0225     spin_lock_irqsave(&pool->lock, flags);
0226     if (pool->ptr == NULL) {    /* not initialized */
0227         pr_debug("ALSA: seq: pool is not initialized\n");
0228         err = -EINVAL;
0229         goto __error;
0230     }
0231     while (pool->free == NULL && ! nonblock && ! pool->closing) {
0232
0233         set_current_state(TASK_INTERRUPTIBLE);
0234         add_wait_queue(&pool->output_sleep, &wait);
0235         spin_unlock_irqrestore(&pool->lock, flags);
0236         if (mutexp)
0237             mutex_unlock(mutexp);
0238         schedule();
0239         if (mutexp)
0240             mutex_lock(mutexp);
0241         spin_lock_irqsave(&pool->lock, flags);
0242         remove_wait_queue(&pool->output_sleep, &wait);
0243         /* interrupted? */
0244         if (signal_pending(current)) {
0245             err = -ERESTARTSYS;
0246             goto __error;
0247         }
0248     }
0249     if (pool->closing) { /* closing.. */
0250         err = -ENOMEM;
0251         goto __error;
0252     }
0253
0254     cell = pool->free;
0255     if (cell) {
0256         int used;
0257         pool->free = cell->next;
0258         atomic_inc(&pool->counter);
0259         used = atomic_read(&pool->counter);
0260         if (pool->max_used < used)
0261             pool->max_used = used;
0262         pool->event_alloc_success++;
0263         /* clear cell pointers */
0264         cell->next = NULL;
0265         err = 0;
0266     } else
0267         pool->event_alloc_failures++;
0268     *cellp = cell;
0269
0270 __error:
0271     spin_unlock_irqrestore(&pool->lock, flags);
0272     return err;
0273 }
0274
0275
0276 /*
0277  * duplicate the event to a cell.
0278  * if the event has external data, the data is decomposed to additional
0279  * cells.
0280  */
0281 int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,
0282               struct snd_seq_event_cell **cellp, int nonblock,
0283               struct file *file, struct mutex *mutexp)
0284 {
0285     int ncells, err;
0286     unsigned int extlen;
0287     struct snd_seq_event_cell *cell;
0288
0289     *cellp = NULL;
0290
0291     ncells = 0;
0292     extlen = 0;
0293     if (snd_seq_ev_is_variable(event)) {
0294         extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
0295         ncells = DIV_ROUND_UP(extlen, sizeof(struct snd_seq_event));
0296     }
0297     if (ncells >= pool->total_elements)
0298         return -ENOMEM;
0299
0300     err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp);
0301     if (err < 0)
0302         return err;
0303
0304     /* copy the event */
0305     cell->event = *event;
0306
0307     /* decompose */
0308     if (snd_seq_ev_is_variable(event)) {
0309         int len = extlen;
0310         int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED;
0311         int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR;
0312         struct snd_seq_event_cell *src, *tmp, *tail;
0313         char *buf;
0314
0315         cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED;
0316         cell->event.data.ext.ptr = NULL;
0317
0318         src = (struct snd_seq_event_cell *)event->data.ext.ptr;
0319         buf = (char *)event->data.ext.ptr;
0320         tail = NULL;
0321
0322         while (ncells-- > 0) {
0323             int size = sizeof(struct snd_seq_event);
0324             if (len < size)
0325                 size = len;
0326             err = snd_seq_cell_alloc(pool, &tmp, nonblock, file,
0327                          mutexp);
0328             if (err < 0)
0329                 goto __error;
0330             if (cell->event.data.ext.ptr == NULL)
0331                 cell->event.data.ext.ptr = tmp;
0332             if (tail)
0333                 tail->next = tmp;
0334             tail = tmp;
0335             /* copy chunk */
0336             if (is_chained && src) {
0337                 tmp->event = src->event;
0338                 src = src->next;
0339             } else if (is_usrptr) {
0340                 if (copy_from_user(&tmp->event, (char __force __user *)buf, size)) {
0341                     err = -EFAULT;
0342                     goto __error;
0343                 }
0344             } else {
0345                 memcpy(&tmp->event, buf, size);
0346             }
0347             buf += size;
0348             len -= size;
0349         }
0350     }
0351
0352     *cellp = cell;
0353     return 0;
0354
0355 __error:
0356     snd_seq_cell_free(cell);
0357     return err;
0358 }
0359
0360
0361 /* poll wait */
0362 int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file,
0363                poll_table *wait)
0364 {
0365     poll_wait(file, &pool->output_sleep, wait);
0366     return snd_seq_output_ok(pool);
0367 }
0368
0369
0370 /* allocate room specified number of events */
0371 int snd_seq_pool_init(struct snd_seq_pool *pool)
0372 {
0373     int cell;
0374     struct snd_seq_event_cell *cellptr;
0375
0376     if (snd_BUG_ON(!pool))
0377         return -EINVAL;
0378
0379     cellptr = kvmalloc_array(sizeof(struct snd_seq_event_cell), pool->size,
0380                  GFP_KERNEL);
0381     if (!cellptr)
0382         return -ENOMEM;
0383
0384     /* add new cells to the free cell list */
0385     spin_lock_irq(&pool->lock);
0386     if (pool->ptr) {
0387         spin_unlock_irq(&pool->lock);
0388         kvfree(cellptr);
0389         return 0;
0390     }
0391
0392     pool->ptr = cellptr;
0393     pool->free = NULL;
0394
0395     for (cell = 0; cell < pool->size; cell++) {
0396         cellptr = pool->ptr + cell;
0397         cellptr->pool = pool;
0398         cellptr->next = pool->free;
0399         pool->free = cellptr;
0400     }
0401     pool->room = (pool->size + 1) / 2;
0402
0403     /* init statistics */
0404     pool->max_used = 0;
0405     pool->total_elements = pool->size;
0406     spin_unlock_irq(&pool->lock);
0407     return 0;
0408 }
0409
0410 /* refuse the further insertion to the pool */
0411 void snd_seq_pool_mark_closing(struct snd_seq_pool *pool)
0412 {
0413     unsigned long flags;
0414
0415     if (snd_BUG_ON(!pool))
0416         return;
0417     spin_lock_irqsave(&pool->lock, flags);
0418     pool->closing = 1;
0419     spin_unlock_irqrestore(&pool->lock, flags);
0420 }
0421
0422 /* remove events */
0423 int snd_seq_pool_done(struct snd_seq_pool *pool)
0424 {
0425     struct snd_seq_event_cell *ptr;
0426
0427     if (snd_BUG_ON(!pool))
0428         return -EINVAL;
0429
0430     /* wait for closing all threads */
0431     if (waitqueue_active(&pool->output_sleep))
0432         wake_up(&pool->output_sleep);
0433
0434     while (atomic_read(&pool->counter) > 0)
0435         schedule_timeout_uninterruptible(1);
0436
0437     /* release all resources */
0438     spin_lock_irq(&pool->lock);
0439     ptr = pool->ptr;
0440     pool->ptr = NULL;
0441     pool->free = NULL;
0442     pool->total_elements = 0;
0443     spin_unlock_irq(&pool->lock);
0444
0445     kvfree(ptr);
0446
0447     spin_lock_irq(&pool->lock);
0448     pool->closing = 0;
0449     spin_unlock_irq(&pool->lock);
0450
0451     return 0;
0452 }
0453
0454
0455 /* init new memory pool */
0456 struct snd_seq_pool *snd_seq_pool_new(int poolsize)
0457 {
0458     struct snd_seq_pool *pool;
0459
0460     /* create pool block */
0461     pool = kzalloc(sizeof(*pool), GFP_KERNEL);
0462     if (!pool)
0463         return NULL;
0464     spin_lock_init(&pool->lock);
0465     pool->ptr = NULL;
0466     pool->free = NULL;
0467     pool->total_elements = 0;
0468     atomic_set(&pool->counter, 0);
0469     pool->closing = 0;
0470     init_waitqueue_head(&pool->output_sleep);
0471
0472     pool->size = poolsize;
0473
0474     /* init statistics */
0475     pool->max_used = 0;
0476     return pool;
0477 }
0478
0479 /* remove memory pool */
0480 int snd_seq_pool_delete(struct snd_seq_pool **ppool)
0481 {
0482     struct snd_seq_pool *pool = *ppool;
0483
0484     *ppool = NULL;
0485     if (pool == NULL)
0486         return 0;
0487     snd_seq_pool_mark_closing(pool);
0488     snd_seq_pool_done(pool);
0489     kfree(pool);
0490     return 0;
0491 }
0492
0493 /* exported to seq_clientmgr.c */
0494 void snd_seq_info_pool(struct snd_info_buffer *buffer,
0495                struct snd_seq_pool *pool, char *space)
0496 {
0497     if (pool == NULL)
0498         return;
0499     snd_iprintf(buffer, "%sPool size          : %d\n", space, pool->total_elements);
0500     snd_iprintf(buffer, "%sCells in use       : %d\n", space, atomic_read(&pool->counter));
0501     snd_iprintf(buffer, "%sPeak cells in use  : %d\n", space, pool->max_used);
0502     snd_iprintf(buffer, "%sAlloc success      : %d\n", space, pool->event_alloc_success);
0503     snd_iprintf(buffer, "%sAlloc failures     : %d\n", space, pool->event_alloc_failures);
0504 }