seq_memory.c

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/*
 *  ALSA sequencer Memory Manager
 *  Copyright (c) 1998 by Frank van de Pol <[email protected]>
 *                        Jaroslav Kysela <[email protected]>
 *                2000 by Takashi Iwai <[email protected]>
 *
 *   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 <linux/init.h>
#include <linux/export.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 __force __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 = roundup(len, 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 __force __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;

    if (snd_BUG_ON(!cell))
        return;
    pool = cell->pool;
    if (snd_BUG_ON(!pool))
        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 __force __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;

    if (snd_BUG_ON(!pool))
        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;

    if (snd_BUG_ON(!pool))
        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);
}