/*
* sum ring buffer shared memory area
*/
static int shm_sum_create_or_connect(snd_pcm_direct_t *dmix)
{
struct shmid_ds buf;
int tmpid, err;
size_t size;
size = dmix->shmptr->s.channels *
dmix->shmptr->s.buffer_size *
sizeof(signed int);
retryshm:
dmix->u.dmix.shmid_sum = shmget(dmix->ipc_key + 1, size,
IPC_CREAT | dmix->ipc_perm);
err = -errno;
if (dmix->u.dmix.shmid_sum < 0){
if (errno == EINVAL)
if ((tmpid = shmget(dmix->ipc_key + 1, 0, dmix->ipc_perm)) != -1)
if (!shmctl(tmpid, IPC_STAT, &buf))
if (!buf.shm_nattch)
/* no users so destroy the segment */
if (!shmctl(tmpid, IPC_RMID, NULL))
goto retryshm;
return err;
}
dmix->u.dmix.sum_buffer = shmat(dmix->u.dmix.shmid_sum, 0, 0);
if (dmix->u.dmix.sum_buffer == (void *) -1) {
shm_sum_discard(dmix);
return -errno;
}
mlock(dmix->u.dmix.sum_buffer, size);
return 0;
}
static void dmix_server_free(snd_pcm_direct_t *dmix)
{
/* remove the memory region */
shm_sum_create_or_connect(dmix);
shm_sum_discard(dmix);
}
