From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Date: Tue, 26 Apr 2022 14:49:33 +0000 (+0300)
Subject: tty: Rework receive flow control char logic
X-Git-Tag: v5.19-rc1~47^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=25e02ba60f0fbe65ba07553b5b2b8867726273c4;p=thirdparty%2Fkernel%2Flinux.git

tty: Rework receive flow control char logic

Add a helper to check if the character is a flow control one. This
rework prepares for adding lookahead done check cleanly to
n_tty_receive_char_flow_ctrl() between n_tty_is_char_flow_ctrl() and
the actions taken on the flow control characters.

No functional changes intended.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220426144935.54893-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 88af1cdd2fd15..640c9e8710449 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1220,20 +1220,26 @@ n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
 		process_echoes(tty);
 }
 
+static bool n_tty_is_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
+{
+	return c == START_CHAR(tty) || c == STOP_CHAR(tty);
+}
+
 /* Returns true if c is consumed as flow-control character */
 static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
 {
+	if (!n_tty_is_char_flow_ctrl(tty, c))
+		return false;
+
 	if (c == START_CHAR(tty)) {
 		start_tty(tty);
 		process_echoes(tty);
 		return true;
 	}
-	if (c == STOP_CHAR(tty)) {
-		stop_tty(tty);
-		return true;
-	}
 
-	return false;
+	/* STOP_CHAR */
+	stop_tty(tty);
+	return true;
 }
 
 static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)