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Sourcecode: alsa-driver version File versions

seq_memory.c

/*
 *  ALSA sequencer Memory Manager
 *  Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
 *                        Jaroslav Kysela <perex@suse.cz>
 *                2000 by Takashi Iwai <tiwai@suse.de>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <sound/core.h>

#include <sound/seq_kernel.h>
#include "seq_memory.h"
#include "seq_queue.h"
#include "seq_info.h"
#include "seq_lock.h"

static inline int snd_seq_pool_available(struct snd_seq_pool *pool)
{
      return pool->total_elements - atomic_read(&pool->counter);
}

static inline int snd_seq_output_ok(struct snd_seq_pool *pool)
{
      return snd_seq_pool_available(pool) >= pool->room;
}

/*
 * Variable length event:
 * The event like sysex uses variable length type.
 * The external data may be stored in three different formats.
 * 1) kernel space
 *    This is the normal case.
 *      ext.data.len = length
 *      ext.data.ptr = buffer pointer
 * 2) user space
 *    When an event is generated via read(), the external data is
 *    kept in user space until expanded.
 *      ext.data.len = length | SNDRV_SEQ_EXT_USRPTR
 *      ext.data.ptr = userspace pointer
 * 3) chained cells
 *    When the variable length event is enqueued (in prioq or fifo),
 *    the external data is decomposed to several cells.
 *      ext.data.len = length | SNDRV_SEQ_EXT_CHAINED
 *      ext.data.ptr = the additiona cell head
 *         -> cell.next -> cell.next -> ..
 */

/*
 * exported:
 * call dump function to expand external data.
 */

static int get_var_len(const struct snd_seq_event *event)
{
      if ((event->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
            return -EINVAL;

      return event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
}

int snd_seq_dump_var_event(const struct snd_seq_event *event,
                     snd_seq_dump_func_t func, void *private_data)
{
      int len, err;
      struct snd_seq_event_cell *cell;

      if ((len = get_var_len(event)) <= 0)
            return len;

      if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
            char buf[32];
            char __user *curptr = (char __user *)event->data.ext.ptr;
            while (len > 0) {
                  int size = sizeof(buf);
                  if (len < size)
                        size = len;
                  if (copy_from_user(buf, curptr, size))
                        return -EFAULT;
                  err = func(private_data, buf, size);
                  if (err < 0)
                        return err;
                  curptr += size;
                  len -= size;
            }
            return 0;
      } if (! (event->data.ext.len & SNDRV_SEQ_EXT_CHAINED)) {
            return func(private_data, event->data.ext.ptr, len);
      }

      cell = (struct snd_seq_event_cell *)event->data.ext.ptr;
      for (; len > 0 && cell; cell = cell->next) {
            int size = sizeof(struct snd_seq_event);
            if (len < size)
                  size = len;
            err = func(private_data, &cell->event, size);
            if (err < 0)
                  return err;
            len -= size;
      }
      return 0;
}

EXPORT_SYMBOL(snd_seq_dump_var_event);


/*
 * exported:
 * expand the variable length event to linear buffer space.
 */

static int seq_copy_in_kernel(char **bufptr, const void *src, int size)
{
      memcpy(*bufptr, src, size);
      *bufptr += size;
      return 0;
}

static int seq_copy_in_user(char __user **bufptr, const void *src, int size)
{
      if (copy_to_user(*bufptr, src, size))
            return -EFAULT;
      *bufptr += size;
      return 0;
}

int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,
                       int in_kernel, int size_aligned)
{
      int len, newlen;
      int err;

      if ((len = get_var_len(event)) < 0)
            return len;
      newlen = len;
      if (size_aligned > 0)
            newlen = ((len + size_aligned - 1) / size_aligned) * size_aligned;
      if (count < newlen)
            return -EAGAIN;

      if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
            if (! in_kernel)
                  return -EINVAL;
            if (copy_from_user(buf, (void __user *)event->data.ext.ptr, len))
                  return -EFAULT;
            return newlen;
      }
      err = snd_seq_dump_var_event(event,
                             in_kernel ? (snd_seq_dump_func_t)seq_copy_in_kernel :
                             (snd_seq_dump_func_t)seq_copy_in_user,
                             &buf);
      return err < 0 ? err : newlen;
}

EXPORT_SYMBOL(snd_seq_expand_var_event);

/*
 * release this cell, free extended data if available
 */

static inline void free_cell(struct snd_seq_pool *pool,
                       struct snd_seq_event_cell *cell)
{
      cell->next = pool->free;
      pool->free = cell;
      atomic_dec(&pool->counter);
}

void snd_seq_cell_free(struct snd_seq_event_cell * cell)
{
      unsigned long flags;
      struct snd_seq_pool *pool;

      snd_assert(cell != NULL, return);
      pool = cell->pool;
      snd_assert(pool != NULL, return);

      spin_lock_irqsave(&pool->lock, flags);
      free_cell(pool, cell);
      if (snd_seq_ev_is_variable(&cell->event)) {
            if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) {
                  struct snd_seq_event_cell *curp, *nextptr;
                  curp = cell->event.data.ext.ptr;
                  for (; curp; curp = nextptr) {
                        nextptr = curp->next;
                        curp->next = pool->free;
                        free_cell(pool, curp);
                  }
            }
      }
      if (waitqueue_active(&pool->output_sleep)) {
            /* has enough space now? */
            if (snd_seq_output_ok(pool))
                  wake_up(&pool->output_sleep);
      }
      spin_unlock_irqrestore(&pool->lock, flags);
}


/*
 * allocate an event cell.
 */
static int snd_seq_cell_alloc(struct snd_seq_pool *pool,
                        struct snd_seq_event_cell **cellp,
                        int nonblock, struct file *file)
{
      struct snd_seq_event_cell *cell;
      unsigned long flags;
      int err = -EAGAIN;
      wait_queue_t wait;

      if (pool == NULL)
            return -EINVAL;

      *cellp = NULL;

      init_waitqueue_entry(&wait, current);
      spin_lock_irqsave(&pool->lock, flags);
      if (pool->ptr == NULL) {      /* not initialized */
            snd_printd("seq: pool is not initialized\n");
            err = -EINVAL;
            goto __error;
      }
      while (pool->free == NULL && ! nonblock && ! pool->closing) {

            set_current_state(TASK_INTERRUPTIBLE);
            add_wait_queue(&pool->output_sleep, &wait);
            spin_unlock_irq(&pool->lock);
            schedule();
            spin_lock_irq(&pool->lock);
            remove_wait_queue(&pool->output_sleep, &wait);
            /* interrupted? */
            if (signal_pending(current)) {
                  err = -ERESTARTSYS;
                  goto __error;
            }
      }
      if (pool->closing) { /* closing.. */
            err = -ENOMEM;
            goto __error;
      }

      cell = pool->free;
      if (cell) {
            int used;
            pool->free = cell->next;
            atomic_inc(&pool->counter);
            used = atomic_read(&pool->counter);
            if (pool->max_used < used)
                  pool->max_used = used;
            pool->event_alloc_success++;
            /* clear cell pointers */
            cell->next = NULL;
            err = 0;
      } else
            pool->event_alloc_failures++;
      *cellp = cell;

__error:
      spin_unlock_irqrestore(&pool->lock, flags);
      return err;
}


/*
 * duplicate the event to a cell.
 * if the event has external data, the data is decomposed to additional
 * cells.
 */
int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,
                  struct snd_seq_event_cell **cellp, int nonblock,
                  struct file *file)
{
      int ncells, err;
      unsigned int extlen;
      struct snd_seq_event_cell *cell;

      *cellp = NULL;

      ncells = 0;
      extlen = 0;
      if (snd_seq_ev_is_variable(event)) {
            extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
            ncells = (extlen + sizeof(struct snd_seq_event) - 1) / sizeof(struct snd_seq_event);
      }
      if (ncells >= pool->total_elements)
            return -ENOMEM;

      err = snd_seq_cell_alloc(pool, &cell, nonblock, file);
      if (err < 0)
            return err;

      /* copy the event */
      cell->event = *event;

      /* decompose */
      if (snd_seq_ev_is_variable(event)) {
            int len = extlen;
            int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED;
            int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR;
            struct snd_seq_event_cell *src, *tmp, *tail;
            char *buf;

            cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED;
            cell->event.data.ext.ptr = NULL;

            src = (struct snd_seq_event_cell *)event->data.ext.ptr;
            buf = (char *)event->data.ext.ptr;
            tail = NULL;

            while (ncells-- > 0) {
                  int size = sizeof(struct snd_seq_event);
                  if (len < size)
                        size = len;
                  err = snd_seq_cell_alloc(pool, &tmp, nonblock, file);
                  if (err < 0)
                        goto __error;
                  if (cell->event.data.ext.ptr == NULL)
                        cell->event.data.ext.ptr = tmp;
                  if (tail)
                        tail->next = tmp;
                  tail = tmp;
                  /* copy chunk */
                  if (is_chained && src) {
                        tmp->event = src->event;
                        src = src->next;
                  } else if (is_usrptr) {
                        if (copy_from_user(&tmp->event, (char __user *)buf, size)) {
                              err = -EFAULT;
                              goto __error;
                        }
                  } else {
                        memcpy(&tmp->event, buf, size);
                  }
                  buf += size;
                  len -= size;
            }
      }

      *cellp = cell;
      return 0;

__error:
      snd_seq_cell_free(cell);
      return err;
}
  

/* poll wait */
int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file,
                     poll_table *wait)
{
      poll_wait(file, &pool->output_sleep, wait);
      return snd_seq_output_ok(pool);
}


/* allocate room specified number of events */
int snd_seq_pool_init(struct snd_seq_pool *pool)
{
      int cell;
      struct snd_seq_event_cell *cellptr;
      unsigned long flags;

      snd_assert(pool != NULL, return -EINVAL);
      if (pool->ptr)                /* should be atomic? */
            return 0;

      pool->ptr = vmalloc(sizeof(struct snd_seq_event_cell) * pool->size);
      if (pool->ptr == NULL) {
            snd_printd("seq: malloc for sequencer events failed\n");
            return -ENOMEM;
      }

      /* add new cells to the free cell list */
      spin_lock_irqsave(&pool->lock, flags);
      pool->free = NULL;

      for (cell = 0; cell < pool->size; cell++) {
            cellptr = pool->ptr + cell;
            cellptr->pool = pool;
            cellptr->next = pool->free;
            pool->free = cellptr;
      }
      pool->room = (pool->size + 1) / 2;

      /* init statistics */
      pool->max_used = 0;
      pool->total_elements = pool->size;
      spin_unlock_irqrestore(&pool->lock, flags);
      return 0;
}

/* remove events */
int snd_seq_pool_done(struct snd_seq_pool *pool)
{
      unsigned long flags;
      struct snd_seq_event_cell *ptr;
      int max_count = 5 * HZ;

      snd_assert(pool != NULL, return -EINVAL);

      /* wait for closing all threads */
      spin_lock_irqsave(&pool->lock, flags);
      pool->closing = 1;
      spin_unlock_irqrestore(&pool->lock, flags);

      if (waitqueue_active(&pool->output_sleep))
            wake_up(&pool->output_sleep);

      while (atomic_read(&pool->counter) > 0) {
            if (max_count == 0) {
                  snd_printk(KERN_WARNING "snd_seq_pool_done timeout: %d cells remain\n", atomic_read(&pool->counter));
                  break;
            }
            schedule_timeout_uninterruptible(1);
            max_count--;
      }
      
      /* release all resources */
      spin_lock_irqsave(&pool->lock, flags);
      ptr = pool->ptr;
      pool->ptr = NULL;
      pool->free = NULL;
      pool->total_elements = 0;
      spin_unlock_irqrestore(&pool->lock, flags);

      vfree(ptr);

      spin_lock_irqsave(&pool->lock, flags);
      pool->closing = 0;
      spin_unlock_irqrestore(&pool->lock, flags);

      return 0;
}


/* init new memory pool */
struct snd_seq_pool *snd_seq_pool_new(int poolsize)
{
      struct snd_seq_pool *pool;

      /* create pool block */
      pool = kzalloc(sizeof(*pool), GFP_KERNEL);
      if (pool == NULL) {
            snd_printd("seq: malloc failed for pool\n");
            return NULL;
      }
      spin_lock_init(&pool->lock);
      pool->ptr = NULL;
      pool->free = NULL;
      pool->total_elements = 0;
      atomic_set(&pool->counter, 0);
      pool->closing = 0;
      init_waitqueue_head(&pool->output_sleep);
      
      pool->size = poolsize;

      /* init statistics */
      pool->max_used = 0;
      return pool;
}

/* remove memory pool */
int snd_seq_pool_delete(struct snd_seq_pool **ppool)
{
      struct snd_seq_pool *pool = *ppool;

      *ppool = NULL;
      if (pool == NULL)
            return 0;
      snd_seq_pool_done(pool);
      kfree(pool);
      return 0;
}

/* initialize sequencer memory */
int __init snd_sequencer_memory_init(void)
{
      return 0;
}

/* release sequencer memory */
void __exit snd_sequencer_memory_done(void)
{
}


/* exported to seq_clientmgr.c */
void snd_seq_info_pool(struct snd_info_buffer *buffer,
                   struct snd_seq_pool *pool, char *space)
{
      if (pool == NULL)
            return;
      snd_iprintf(buffer, "%sPool size          : %d\n", space, pool->total_elements);
      snd_iprintf(buffer, "%sCells in use       : %d\n", space, atomic_read(&pool->counter));
      snd_iprintf(buffer, "%sPeak cells in use  : %d\n", space, pool->max_used);
      snd_iprintf(buffer, "%sAlloc success      : %d\n", space, pool->event_alloc_success);
      snd_iprintf(buffer, "%sAlloc failures     : %d\n", space, pool->event_alloc_failures);
}

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