linux-kernel - [PATCH 07/15] tty: invert return values of tty_{,un}throttle

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Date:   Tue, 19 Sep 2023 10:51:48 +0200
From:   "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
Subject: [PATCH 07/15] tty: invert return values of tty_{,un}throttle_safe()

If tty_{,un}throttle_safe() returned true on success (similar to
*_trylock()), it would make the conditions in callers more obvious. So
perform the switch to these inverted values (and fix the callers).

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/n_tty.c     |  4 ++--
 drivers/tty/tty_ioctl.c | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index b34e6612aef6..f252d0b5a434 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -253,7 +253,7 @@ static void n_tty_check_throttle(struct tty_struct *tty)
 		tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
 		if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE)
 			break;
-	} while (tty_throttle_safe(tty));
+	} while (!tty_throttle_safe(tty));
 
 	__tty_set_flow_change(tty, 0);
 }
@@ -282,7 +282,7 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
 			break;
 
 		n_tty_kick_worker(tty);
-	} while (tty_unthrottle_safe(tty));
+	} while (!tty_unthrottle_safe(tty));
 
 	__tty_set_flow_change(tty, 0);
 }
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index ba60fcf518e0..fb2f1ac5172f 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -124,16 +124,16 @@ EXPORT_SYMBOL(tty_unthrottle);
  *	conditions when throttling is conditional on factors evaluated prior to
  *	throttling.
  *
- *	Returns false if tty is throttled (or was already throttled)
+ *	Returns true if tty is throttled (or was already throttled)
  */
 bool tty_throttle_safe(struct tty_struct *tty)
 {
-	bool ret = false;
+	bool ret = true;
 
 	mutex_lock(&tty->throttle_mutex);
 	if (!tty_throttled(tty)) {
 		if (tty->flow_change != TTY_THROTTLE_SAFE)
-			ret = true;
+			ret = false;
 		else {
 			set_bit(TTY_THROTTLED, &tty->flags);
 			if (tty->ops->throttle)
@@ -154,16 +154,16 @@ bool tty_throttle_safe(struct tty_struct *tty)
  *	unthrottle due to race conditions when unthrottling is conditional
  *	on factors evaluated prior to unthrottling.
  *
- *	Returns false if tty is unthrottled (or was already unthrottled)
+ *	Returns true if tty is unthrottled (or was already unthrottled)
  */
 bool tty_unthrottle_safe(struct tty_struct *tty)
 {
-	bool ret = false;
+	bool ret = true;
 
 	mutex_lock(&tty->throttle_mutex);
 	if (tty_throttled(tty)) {
 		if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
-			ret = true;
+			ret = false;
 		else {
 			clear_bit(TTY_THROTTLED, &tty->flags);
 			if (tty->ops->unthrottle)
-- 
2.42.0