static enum ach_status wrlock(ach_channel_t * chan)
{
enum ach_status r = chan_lock(chan) ;
if( ACH_OK != r ) return r;
chan->shm->sync.dirty = 1;
return ACH_OK;
}
static enum ach_status
rdlock( ach_channel_t *chan, int wait, const struct timespec *abstime ) {
ach_header_t *shm = chan->shm;
{
enum ach_status r = chan_lock(chan);
if( ACH_OK != r ) return r;
}
enum ach_status r = ACH_BUG;
while(ACH_BUG == r) {
if( chan->cancel ) { /* check operation cancelled */
pthread_mutex_unlock( &shm->sync.mutex );
r = ACH_CANCELED;
} else if( !wait ) r = ACH_OK; /* check no wait */
else if ( chan->seq_num != shm->last_seq ) r = ACH_OK; /* check if got a frame */
/* else condition wait */
else {
int i = abstime ?
pthread_cond_timedwait( &shm->sync.cond, &shm->sync.mutex, abstime ) :
pthread_cond_wait( &shm->sync.cond, &shm->sync.mutex );
enum ach_status c = check_lock(i, chan, 1);
if( ACH_OK != c ) r = c;
/* check r and condition next iteration */
}
}
return r;
}
static enum ach_status
rdlock_wait(ach_channel_t * chan, const struct timespec *reltime)
{
int res;
struct ach_header *shm = chan->shm;
volatile uint64_t *c_seq = &chan->seq_num, *s_seq = &shm->last_seq;
volatile unsigned int *cancel = &chan->cancel;
enum ach_status r;
for(;;) {
/* do the wait */
if (reltime->tv_sec != 0 || reltime->tv_nsec != 0) {
res = wait_event_interruptible_timeout( shm->sync. readq,
((*c_seq != *s_seq) || *cancel),
timespec_to_jiffies (reltime) );
if (0 == res) return ACH_TIMEOUT;
} else {
res = wait_event_interruptible( shm->sync.readq,
((*c_seq != *s_seq) || *cancel) );
}
/* check what happened */
if (-ERESTARTSYS == res) return ACH_EINTR;
if( res < 0 ) {
ACH_ERRF("ach bug: rdlock_wait(), "
"could not wait for event, "
"timeout: (%lu,%ld), result=%d\n",
reltime->tv_sec, reltime->tv_nsec, res);
return ACH_BUG;
}
r = chan_lock( chan );
/* Check condition with the lock held in case someone
* else flushed the channel, or someone else unset the
* cancel */
if( (*c_seq != *s_seq) || (ACH_OK != r) || *cancel ) {
return r;
}
rt_mutex_unlock(&shm->sync.mutex);
}
}
static unsigned int ach_ch_poll(struct file *file, poll_table * wait)
{
unsigned int mask = POLLOUT | POLLWRNORM;
struct ach_ch_file *ch_file = (struct ach_ch_file *)file->private_data;
struct ach_header *shm = ch_file->shm;
enum ach_status r;
/* KDEBUG1("In ach_ch_poll (minor=%d)\n", ch_file->dev->minor); */
/* Add ourselves wait queue */
poll_wait(file, &shm->sync.readq, wait);
/* Lock channel and check what happened */
r = chan_lock(ch_file);
if( ACH_OK != r ) return -get_errno(r);
if (ch_file->seq_num != shm->last_seq) {
mask |= POLLIN | POLLRDNORM;
}
rt_mutex_unlock(&shm->sync.mutex);
return mask;
}
static enum ach_status
rdlock(ach_channel_t * chan, int wait, const struct timespec *reltime)
{
if( wait ) return rdlock_wait(chan, reltime);
else return chan_lock(chan);
}
