tty: remove unused tty_throttle

The last user was removed in commit e91e52e42814 (n_tty: Fix stuck
throttled driver) in 2013. So remove exported tty_throttle completely.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210510065923.5112-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index aa9ecc8be990bfc64ba851fd930bb284a5e2ab49..75885d5027490c2848a8338b837c45a50222c23c 100644 (file)
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -96,28 +96,6 @@ void tty_driver_flush_buffer(struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_driver_flush_buffer);
 
-/**
- *     tty_throttle            -       flow control
- *     @tty: terminal
- *
- *     Indicate that a tty should stop transmitting data down the stack.
- *     Takes the termios rwsem to protect against parallel throttle/unthrottle
- *     and also to ensure the driver can consistently reference its own
- *     termios data at this point when implementing software flow control.
- */
-
-void tty_throttle(struct tty_struct *tty)
-{
-       down_write(&tty->termios_rwsem);
-       /* check TTY_THROTTLED first so it indicates our state */
-       if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
-           tty->ops->throttle)
-               tty->ops->throttle(tty);
-       tty->flow_change = 0;
-       up_write(&tty->termios_rwsem);
-}
-EXPORT_SYMBOL(tty_throttle);
-
 /**
  *     tty_unthrottle          -       flow control
  *     @tty: terminal
@@ -146,10 +124,11 @@ EXPORT_SYMBOL(tty_unthrottle);
  *     tty_throttle_safe       -       flow control
  *     @tty: terminal
  *
- *     Similar to tty_throttle() but will only attempt throttle
- *     if tty->flow_change is TTY_THROTTLE_SAFE. Prevents an accidental
- *     throttle due to race conditions when throttling is conditional
- *     on factors evaluated prior to throttling.
+ *     Indicate that a tty should stop transmitting data down the stack.
+ *     tty_throttle_safe will only attempt throttle if tty->flow_change is
+ *     TTY_THROTTLE_SAFE. Prevents an accidental throttle due to race
+ *     conditions when throttling is conditional on factors evaluated prior to
+ *     throttling.
  *
  *     Returns 0 if tty is throttled (or was already throttled)
  */

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 5cf6b2e7331b7f80a1dfa29cf925d94e3597e350..4c0c7ca1d9a443b7b449722c8a524d3ea3ee2dba 100644 (file)
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -461,7 +461,6 @@ extern int tty_put_char(struct tty_struct *tty, unsigned char c);
 extern unsigned int tty_chars_in_buffer(struct tty_struct *tty);
 extern unsigned int tty_write_room(struct tty_struct *tty);
 extern void tty_driver_flush_buffer(struct tty_struct *tty);
-extern void tty_throttle(struct tty_struct *tty);
 extern void tty_unthrottle(struct tty_struct *tty);
 extern int tty_throttle_safe(struct tty_struct *tty);
 extern int tty_unthrottle_safe(struct tty_struct *tty);

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index a4694bb125cc8a6ac4881993d5b41a32f48159b1..448f8ee6db6e303a4c2ad77c465dada69fe85278 100644 (file)
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -136,7 +136,7 @@
  *     the line discipline are close to full, and it should somehow
  *     signal that no more characters should be sent to the tty.
  *
- *     Optional: Always invoke via tty_throttle(), called under the
+ *     Optional: Always invoke via tty_throttle_safe(), called under the
  *     termios lock.
  * 
  * void (*unthrottle)(struct tty_struct * tty);