Revert "tty: tty_port: add workqueue to flip TTY buffer"

This reverts commit d000422a46aad32217cf1be747eb61d641baae2f.

It is reported by many to cause boot failures, so must be reverted.

Cc: Xin Zhao <jackzxcui1989@163.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/d1942304-ee30-478d-90fb-279519f3ae81@samsung.com
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 0 insertions, 21 deletions

diff --git a/include/linux/tty_buffer.h b/include/linux/tty_buffer.h
index 48adcb0e8ff3..31125e3be3c5 100644
--- a/include/linux/tty_buffer.h
+++ b/include/linux/tty_buffer.h
@@ -34,7 +34,6 @@ static inline u8 *flag_buf_ptr(struct tty_buffer *b, unsigned int ofs)
 
 struct tty_bufhead {
 	struct tty_buffer *head;	/* Queue head */
-	struct workqueue_struct *flip_wq;
 	struct work_struct work;
 	struct mutex	   lock;
 	atomic_t	   priority;
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 9c65854f7d94..188ee9b768eb 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -69,10 +69,6 @@ struct serial_struct;
  *	Do not create numbered ``/dev`` nodes. For example, create
  *	``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
  *	driver for a single tty device is being allocated.
- *
- * @TTY_DRIVER_CUSTOM_WORKQUEUE:
- *	Do not create workqueue when tty_register_driver(). When set, flip
- *	buffer workqueue shall be set by tty_port_link_wq() for every port.
  */
 enum tty_driver_flag {
 	TTY_DRIVER_INSTALLED		= BIT(0),
@@ -83,7 +79,6 @@ enum tty_driver_flag {
 	TTY_DRIVER_HARDWARE_BREAK	= BIT(5),
 	TTY_DRIVER_DYNAMIC_ALLOC	= BIT(6),
 	TTY_DRIVER_UNNUMBERED_NODE	= BIT(7),
-	TTY_DRIVER_CUSTOM_WORKQUEUE	= BIT(8),
 };
 
 enum tty_driver_type {
@@ -511,7 +506,6 @@ struct tty_operations {
  * @flags: tty driver flags (%TTY_DRIVER_)
  * @proc_entry: proc fs entry, used internally
  * @other: driver of the linked tty; only used for the PTY driver
- * @flip_wq: workqueue to queue flip buffer work on
  * @ttys: array of active &struct tty_struct, set by tty_standard_install()
  * @ports: array of &struct tty_port; can be set during initialization by
  *	   tty_port_link_device() and similar
@@ -545,7 +539,6 @@ struct tty_driver {
 	unsigned long	flags;
 	struct proc_dir_entry *proc_entry;
 	struct tty_driver *other;
-	struct workqueue_struct *flip_wq;
 
 	/*
 	 * Pointer to the tty data structures
diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
index c1b87f3c5603..660c254f1efe 100644
--- a/include/linux/tty_port.h
+++ b/include/linux/tty_port.h
@@ -138,7 +138,6 @@ struct tty_port {
 					   kernel */
 
 void tty_port_init(struct tty_port *port);
-void tty_port_link_wq(struct tty_port *port, struct workqueue_struct *flip_wq);
 void tty_port_link_device(struct tty_port *port, struct tty_driver *driver,
 		unsigned index);
 struct device *tty_port_register_device(struct tty_port *port,
@@ -166,18 +165,6 @@ static inline struct tty_port *tty_port_get(struct tty_port *port)
 	return NULL;
 }
 
-/*
- * Never overwrite the workqueue set by tty_port_link_wq().
- * No effect when %TTY_DRIVER_CUSTOM_WORKQUEUE is set, as driver->flip_wq is
- * %NULL.
- */
-static inline void tty_port_link_driver_wq(struct tty_port *port,
-					   struct tty_driver *driver)
-{
-	if (!port->buf.flip_wq)
-		port->buf.flip_wq = driver->flip_wq;
-}
-
 /* If the cts flow control is enabled, return true. */
 static inline bool tty_port_cts_enabled(const struct tty_port *port)
 {