// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer Memory Manager
* Copyright (c) 1998 by Frank van de Pol <[email protected]>
* Jaroslav Kysela <[email protected]>
* 2000 by Takashi Iwai <[email protected]>
*/
#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/mm.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;
}
static int dump_var_event(const struct snd_seq_event *event,
snd_seq_dump_func_t func, void *private_data,
int offset, int maxlen)
{
int len, err;
struct snd_seq_event_cell *cell;
len = get_var_len(event);
if (len <= 0)
return len;
if (len <= offset)
return 0;
if (maxlen && len > offset + maxlen)
len = offset + maxlen;
if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
char buf[32];
char __user *curptr = (char __force __user *)event->data.ext.ptr;
curptr += offset;
len -= offset;
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 + offset,
len - offset);
cell = (struct snd_seq_event_cell *)event->data.ext.ptr;
for (; len > 0 && cell; cell = cell->next) {
int size = sizeof(struct snd_seq_event);
char *curptr = (char *)&cell->event;
if (offset >= size) {
offset -= size;
len -= size;
continue;
}
if (len < size)
size = len;
err = func(private_data, curptr + offset, size - offset);
if (err < 0)
return err;
offset = 0;
len -= size;
}
return 0;
}
int snd_seq_dump_var_event(const struct snd_seq_event *event,
snd_seq_dump_func_t func, void *private_data)
{
return dump_var_event(event, func, private_data, 0, 0);
}
EXPORT_SYMBOL(snd_seq_dump_var_event);
/*
* exported:
* expand the variable length event to linear buffer space.
*/
static int seq_copy_in_kernel(void *ptr, void *src, int size)
{
char **bufptr = ptr;
memcpy(*bufptr, src, size);
*bufptr += size;
return 0;
}
static int seq_copy_in_user(void *ptr, void *src, int size)
{
char __user **bufptr = ptr;
if (copy_to_user(*bufptr, src, size))
return -EFAULT;
*bufptr += size;
return 0;
}
static int expand_var_event(const struct snd_seq_event *event,
int offset, int size, char *buf, bool in_kernel)
{
if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
if (! in_kernel)
return -EINVAL;
if (copy_from_user(buf,
(char __force __user *)event->data.ext.ptr + offset,
size))
return -EFAULT;
return 0;
}
return dump_var_event(event,
in_kernel ? seq_copy_in_kernel : seq_copy_in_user,
&buf, offset, size);
}
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, err;
len = get_var_len(event);
if (len < 0)
return len;
newlen = len;
if (size_aligned > 0)
newlen = roundup(len, size_aligned);
if (count < newlen)
return -EAGAIN;
err = expand_var_event(event, 0, len, buf, in_kernel);
if (err < 0)
return err;
if (len != newlen) {
if (in_kernel)
memset(buf + len, 0, newlen - len);
else if (clear_user((__force void __user *)buf + len,
newlen - len))
return -EFAULT;
}
return newlen;
}
EXPORT_SYMBOL(snd_seq_expand_var_event);
int snd_seq_expand_var_event_at(const struct snd_seq_event *event, int count,
char *buf, int offset)
{
int len, err;
len = get_var_len(event);
if (len < 0)
return len;
if (len <= offset)
return 0;
len -= offset;
if (len > count)
len = count;
err = expand_var_event(event, offset, count, buf, true);
if (err < 0)
return err;
return len;
}
EXPORT_SYMBOL_GPL(snd_seq_expand_var_event_at);
/*
* 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)
{
struct snd_seq_pool *pool;
if (snd_BUG_ON(!cell))
return;
pool = cell->pool;
if (snd_BUG_ON(!pool))
return;
guard(spinlock_irqsave)(&pool->lock);
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);
}
}
/*
* 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 mutex *mutexp)
{
struct snd_seq_event_cell *cell;
unsigned long flags;
int err = -EAGAIN;
wait_queue_entry_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 */
pr_debug("ALSA: 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_irqrestore(&pool->lock, flags);
if (mutexp)
mutex_unlock(mutexp);
schedule();
if (mutexp)
mutex_lock(mutexp);
spin_lock_irqsave(&pool->lock, flags);
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, struct mutex *mutexp)
{
int ncells, err;
unsigned int extlen;
struct snd_seq_event_cell *cell;
int size;
*cellp = NULL;
ncells = 0;
extlen = 0;
if (snd_seq_ev_is_variable(event)) {
extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;
ncells = DIV_ROUND_UP(extlen, sizeof(struct snd_seq_event));
}
if (ncells >= pool->total_elements)
return -ENOMEM;
err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp);
if (err < 0)
return err;
/* copy the event */
size = snd_seq_event_packet_size(event);
memcpy(&cell->ump, event, size);
#if IS_ENABLED(CONFIG_SND_SEQ_UMP)
if (size < sizeof(cell->event))
cell->ump.raw.extra = 0;
#endif
/* 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) {
size = sizeof(struct snd_seq_event);
if (len < size)
size = len;
err = snd_seq_cell_alloc(pool, &tmp, nonblock, file,
mutexp);
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;
if (snd_BUG_ON(!pool))
return -EINVAL;
cellptr = kvmalloc_array(pool->size,
sizeof(struct snd_seq_event_cell),
GFP_KERNEL);
if (!cellptr)
return -ENOMEM;
/* add new cells to the free cell list */
guard(spinlock_irq)(&pool->lock);
if (pool->ptr) {
kvfree(cellptr);
return 0;
}
pool->ptr = cellptr;
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;
return 0;
}
/* refuse the further insertion to the pool */
void snd_seq_pool_mark_closing(struct snd_seq_pool *pool)
{
if (snd_BUG_ON(!pool))
return;
guard(spinlock_irqsave)(&pool->lock);
pool->closing = 1;
}
/* remove events */
int snd_seq_pool_done(struct snd_seq_pool *pool)
{
struct snd_seq_event_cell *ptr;
if (snd_BUG_ON(!pool))
return -EINVAL;
/* wait for closing all threads */
if (waitqueue_active(&pool->output_sleep))
wake_up(&pool->output_sleep);
while (atomic_read(&pool->counter) > 0)
schedule_timeout_uninterruptible(1);
/* release all resources */
scoped_guard(spinlock_irq, &pool->lock) {
ptr = pool->ptr;
pool->ptr = NULL;
pool->free = NULL;
pool->total_elements = 0;
}
kvfree(ptr);
guard(spinlock_irq)(&pool->lock);
pool->closing = 0;
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)
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_mark_closing(pool);
snd_seq_pool_done(pool);
kfree(pool);
return 0;
}
/* 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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