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-rw-r--r--drivers/tty/ipwireless/tty.c3
-rw-r--r--drivers/tty/tty_buffer.c20
-rw-r--r--drivers/usb/gadget/u_serial.c4
-rw-r--r--include/linux/tty.h2
4 files changed, 7 insertions, 22 deletions
diff --git a/drivers/tty/ipwireless/tty.c b/drivers/tty/ipwireless/tty.c
index ebd5bff0f5c1..17ee3bf0926b 100644
--- a/drivers/tty/ipwireless/tty.c
+++ b/drivers/tty/ipwireless/tty.c
@@ -176,9 +176,6 @@ void ipwireless_tty_received(struct ipw_tty *tty, unsigned char *data,
": %d chars not inserted to flip buffer!\n",
length - work);
- /*
- * This may sleep if ->low_latency is set
- */
if (work)
tty_flip_buffer_push(&tty->port);
}
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 765125dff20e..8ebd9f88a6f6 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -351,14 +351,11 @@ EXPORT_SYMBOL(tty_insert_flip_string_flags);
* Takes any pending buffers and transfers their ownership to the
* ldisc side of the queue. It then schedules those characters for
* processing by the line discipline.
- * Note that this function can only be used when the low_latency flag
- * is unset. Otherwise the workqueue won't be flushed.
*/
void tty_schedule_flip(struct tty_port *port)
{
struct tty_bufhead *buf = &port->buf;
- WARN_ON(port->low_latency);
buf->tail->commit = buf->tail->used;
schedule_work(&buf->work);
@@ -482,17 +479,15 @@ static void flush_to_ldisc(struct work_struct *work)
*/
void tty_flush_to_ldisc(struct tty_struct *tty)
{
- if (!tty->port->low_latency)
- flush_work(&tty->port->buf.work);
+ flush_work(&tty->port->buf.work);
}
/**
* tty_flip_buffer_push - terminal
* @port: tty port to push
*
- * Queue a push of the terminal flip buffers to the line discipline. This
- * function must not be called from IRQ context if port->low_latency is
- * set.
+ * Queue a push of the terminal flip buffers to the line discipline.
+ * Can be called from IRQ/atomic context.
*
* In the event of the queue being busy for flipping the work will be
* held off and retried later.
@@ -500,14 +495,7 @@ void tty_flush_to_ldisc(struct tty_struct *tty)
void tty_flip_buffer_push(struct tty_port *port)
{
- struct tty_bufhead *buf = &port->buf;
-
- buf->tail->commit = buf->tail->used;
-
- if (port->low_latency)
- flush_to_ldisc(&buf->work);
- else
- schedule_work(&buf->work);
+ tty_schedule_flip(port);
}
EXPORT_SYMBOL(tty_flip_buffer_push);
diff --git a/drivers/usb/gadget/u_serial.c b/drivers/usb/gadget/u_serial.c
index b369292d4b90..ad0aca812002 100644
--- a/drivers/usb/gadget/u_serial.c
+++ b/drivers/usb/gadget/u_serial.c
@@ -549,8 +549,8 @@ static void gs_rx_push(unsigned long _port)
port->read_started--;
}
- /* Push from tty to ldisc; without low_latency set this is handled by
- * a workqueue, so we won't get callbacks and can hold port_lock
+ /* Push from tty to ldisc; this is handled by a workqueue,
+ * so we won't get callbacks and can hold port_lock
*/
if (do_push)
tty_flip_buffer_push(&port->port);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 90b4fdc8a61f..b90b5c221ff0 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -208,7 +208,7 @@ struct tty_port {
wait_queue_head_t delta_msr_wait; /* Modem status change */
unsigned long flags; /* TTY flags ASY_*/
unsigned char console:1, /* port is a console */
- low_latency:1; /* direct buffer flush */
+ low_latency:1; /* optional: tune for latency */
struct mutex mutex; /* Locking */
struct mutex buf_mutex; /* Buffer alloc lock */
unsigned char *xmit_buf; /* Optional buffer */