tty: Only perform flip buffer flush from tty_buffer_flush()
Now that dropping the buffer lock is not necessary (as result of converting the spin lock to a mutex), the flip buffer flush no longer needs to be handled by the buffer work. Simply signal a flush is required; the buffer work will exit the i/o loop, which allows tty_buffer_flush() to proceed. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -189,19 +189,11 @@ void tty_buffer_flush(struct tty_struct *tty)
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struct tty_port *port = tty->port;
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struct tty_bufhead *buf = &port->buf;
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mutex_lock(&buf->flush_mutex);
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/* If the data is being pushed to the tty layer then we can't
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process it here. Instead set a flag and the flush_to_ldisc
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path will process the flush request before it exits */
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if (test_bit(TTYP_FLUSHING, &port->iflags)) {
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set_bit(TTYP_FLUSHPENDING, &port->iflags);
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mutex_unlock(&buf->flush_mutex);
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wait_event(tty->read_wait,
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test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0);
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return;
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}
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set_bit(TTYP_FLUSHPENDING, &port->iflags);
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mutex_lock(&buf->flush_mutex);
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__tty_buffer_flush(port);
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clear_bit(TTYP_FLUSHPENDING, &port->iflags);
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mutex_unlock(&buf->flush_mutex);
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}
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@ -429,39 +421,26 @@ static void flush_to_ldisc(struct work_struct *work)
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mutex_lock(&buf->flush_mutex);
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if (!test_and_set_bit(TTYP_FLUSHING, &port->iflags)) {
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while (1) {
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struct tty_buffer *head = buf->head;
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int count;
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while (1) {
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struct tty_buffer *head = buf->head;
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int count;
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count = head->commit - head->read;
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if (!count) {
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if (head->next == NULL)
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break;
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buf->head = head->next;
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tty_buffer_free(port, head);
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continue;
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}
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/* Ldisc or user is trying to flush the buffers. */
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if (test_bit(TTYP_FLUSHPENDING, &port->iflags))
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break;
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mutex_unlock(&buf->flush_mutex);
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count = receive_buf(tty, head, count);
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mutex_lock(&buf->flush_mutex);
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/* Ldisc or user is trying to flush the buffers.
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We may have a deferred request to flush the
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input buffer, if so pull the chain under the lock
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and empty the queue */
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if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) {
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__tty_buffer_flush(port);
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clear_bit(TTYP_FLUSHPENDING, &port->iflags);
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wake_up(&tty->read_wait);
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break;
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} else if (!count)
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count = head->commit - head->read;
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if (!count) {
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if (head->next == NULL)
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break;
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buf->head = head->next;
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tty_buffer_free(port, head);
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continue;
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}
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clear_bit(TTYP_FLUSHING, &port->iflags);
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count = receive_buf(tty, head, count);
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if (!count)
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break;
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}
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mutex_unlock(&buf->flush_mutex);
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@ -213,7 +213,6 @@ struct tty_port {
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wait_queue_head_t delta_msr_wait; /* Modem status change */
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unsigned long flags; /* TTY flags ASY_*/
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unsigned long iflags; /* TTYP_ internal flags */
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#define TTYP_FLUSHING 1 /* Flushing to ldisc in progress */
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#define TTYP_FLUSHPENDING 2 /* Queued buffer flush pending */
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unsigned char console:1, /* port is a console */
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low_latency:1; /* direct buffer flush */
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