static void flush_to_ldisc(struct work_struct *work)
{
struct tty_struct *tty =
container_of(work, struct tty_struct, buf.work);
unsigned long flags;
struct tty_ldisc *disc;
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
struct tty_buffer *head;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
count = head->commit - head->read;
if (!count) {
if (head->next == NULL)
break;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
if (!tty->receive_room)
break;
if (count > tty->receive_room)
count = tty->receive_room;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
clear_bit(TTY_FLUSHING, &tty->flags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
__tty_buffer_flush(tty);
clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait);
}
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
}
void tty_buffer_flush(struct tty_struct *tty)
{
unsigned long flags;
spin_lock_irqsave(&tty->buf.lock, flags);
/* If the data is being pushed to the tty layer then we can't
process it here. Instead set a flag and the flush_to_ldisc
path will process the flush request before it exits */
if (test_bit(TTY_FLUSHING, &tty->flags)) {
set_bit(TTY_FLUSHPENDING, &tty->flags);
spin_unlock_irqrestore(&tty->buf.lock, flags);
wait_event(tty->read_wait,
test_bit(TTY_FLUSHPENDING, &tty->flags) == 0);
return;
} else
__tty_buffer_flush(tty);
spin_unlock_irqrestore(&tty->buf.lock, flags);
}
static void flush_to_ldisc(struct work_struct *work)
{
struct tty_struct *tty =
container_of(work, struct tty_struct, buf.work.work);
unsigned long flags;
struct tty_ldisc *disc;
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
struct tty_buffer *head, *tail = tty->buf.tail;
int seen_tail = 0;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
count = head->commit - head->read;
if (!count) {
if (head->next == NULL)
break;
/*
There's a possibility tty might get new buffer
added during the unlock window below. We could
end up spinning in here forever hogging the CPU
completely. To avoid this let's have a rest each
time we processed the tail buffer.
*/
if (tail == head)
seen_tail = 1;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
if (!tty->receive_room || seen_tail) {
schedule_delayed_work(&tty->buf.work, 1);
break;
}
if (count > tty->receive_room)
count = tty->receive_room;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
clear_bit(TTY_FLUSHING, &tty->flags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
__tty_buffer_flush(tty);
clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait);
}
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
}
static void flush_to_ldisc(struct work_struct *work)
{
struct tty_struct *tty =
container_of(work, struct tty_struct, buf.work);
unsigned long flags;
struct tty_ldisc *disc;
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
struct tty_buffer *head;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
unsigned int left = 0;
unsigned int max_space;
count = head->commit - head->read;
if (!count) {
if (head->next == NULL)
break;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
/* update receive room */
spin_lock(&tty->read_lock);
if (tty->update_room_in_ldisc) {
if ((tty->read_cnt == N_TTY_BUF_SIZE - 1) &&
(tty->receive_room ==
N_TTY_BUF_SIZE - 1))
tty->rr_bug++;
left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
}
spin_unlock(&tty->read_lock);
if (!tty->receive_room)
break;
if (tty->update_room_in_ldisc && !left) {
schedule_work(&tty->buf.work);
break;
}
if (tty->update_room_in_ldisc)
max_space = min(left, tty->receive_room);
else
max_space = tty->receive_room;
if (count > max_space)
count = max_space;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
if(tty->start_debug){
dbg_log_event(NULL, "f_t_l_d:head->read",head->read, "head->commit", head->commit,
"receive_room ", tty->receive_room );
}
tty->ldisc_cnt += count;
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
clear_bit(TTY_FLUSHING, &tty->flags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
__tty_buffer_flush(tty);
clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait);
}
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
}