[PATCH 4.2.y-ckt 049/206] tty: Abstract tty buffer work

[Kamal Mostafa]

4.2.8-ckt12 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>

commit e176058f0de53c2346734e5254835e0045364001 upstream.

Introduce API functions to restart and cancel tty buffer work, rather
than manipulate buffer work directly.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/tty/n_tty.c      |  2 +-
 drivers/tty/tty_buffer.c | 10 ++++++++++
 drivers/tty/tty_io.c     |  2 +-
 drivers/tty/tty_port.c   |  2 +-
 include/linux/tty.h      |  2 ++
 5 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index a0398a8..4e27ab9 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -201,7 +201,7 @@ static void n_tty_kick_worker(struct tty_struct *tty)
 		 */
 		WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
 			       "scheduling buffer work for halted ldisc\n");
-		queue_work(system_unbound_wq, &tty->port->buf.work);
+		tty_buffer_restart_work(tty->port);
 	}
 }
 
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 6059177..a0ee0bf 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -577,3 +577,13 @@ void tty_buffer_set_lock_subclass(struct tty_port *port)
 {
 	lockdep_set_subclass(&port->buf.lock, TTY_LOCK_SLAVE);
 }
+
+bool tty_buffer_restart_work(struct tty_port *port)
+{
+	return queue_work(system_unbound_wq, &port->buf.work);
+}
+
+bool tty_buffer_cancel_work(struct tty_port *port)
+{
+	return cancel_work_sync(&port->buf.work);
+}
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d5f54a1..876def68 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1690,7 +1690,7 @@ static void release_tty(struct tty_struct *tty, int idx)
 	tty->port->itty = NULL;
 	if (tty->link)
 		tty->link->port->itty = NULL;
-	cancel_work_sync(&tty->port->buf.work);
+	tty_buffer_cancel_work(tty->port);
 
 	tty_kref_put(tty->link);
 	tty_kref_put(tty);
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 40b3183..892affc 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -131,7 +131,7 @@ EXPORT_SYMBOL(tty_port_free_xmit_buf);
  */
 void tty_port_destroy(struct tty_port *port)
 {
-	cancel_work_sync(&port->buf.work);
+	tty_buffer_cancel_work(port);
 	tty_buffer_free_all(port);
 }
 EXPORT_SYMBOL(tty_port_destroy);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 245524a2..223d905 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -467,6 +467,8 @@ extern void tty_buffer_free_all(struct tty_port *port);
 extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld);
 extern void tty_buffer_init(struct tty_port *port);
 extern void tty_buffer_set_lock_subclass(struct tty_port *port);
+extern bool tty_buffer_restart_work(struct tty_port *port);
+extern bool tty_buffer_cancel_work(struct tty_port *port);
 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
-- 
2.7.4