FAILED: patch "[PATCH] tty: mxser: fix TIOCSSERIAL jiffies conversions" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From be6cf583d24dfe87324dd2830d90fc056e0a6648 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 7 Apr 2021 12:23:31 +0200
Subject: [PATCH] tty: mxser: fix TIOCSSERIAL jiffies conversions

The port close_delay and closing wait parameters set by TIOCSSERIAL are
specified in jiffies, while the values returned by TIOCGSERIAL are
specified in centiseconds.

Add the missing conversions so that TIOCSSERIAL works as expected also
when HZ is not 100.

Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-14-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 4203b64bccdb..914b23071961 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -1208,19 +1208,26 @@ static int mxser_get_serial_info(struct tty_struct *tty,
 {
 	struct mxser_port *info = tty->driver_data;
 	struct tty_port *port = &info->port;
+	unsigned int closing_wait, close_delay;
 
 	if (tty->index == MXSER_PORTS)
 		return -ENOTTY;
 
 	mutex_lock(&port->mutex);
+
+	close_delay = jiffies_to_msecs(info->port.close_delay) / 10;
+	closing_wait = info->port.closing_wait;
+	if (closing_wait != ASYNC_CLOSING_WAIT_NONE)
+		closing_wait = jiffies_to_msecs(closing_wait) / 10;
+
 	ss->type = info->type,
 	ss->line = tty->index,
 	ss->port = info->ioaddr,
 	ss->irq = info->board->irq,
 	ss->flags = info->port.flags,
 	ss->baud_base = info->baud_base,
-	ss->close_delay = info->port.close_delay,
-	ss->closing_wait = info->port.closing_wait,
+	ss->close_delay = close_delay;
+	ss->closing_wait = closing_wait;
 	ss->custom_divisor = info->custom_divisor,
 	mutex_unlock(&port->mutex);
 	return 0;
@@ -1233,7 +1240,7 @@ static int mxser_set_serial_info(struct tty_struct *tty,
 	struct tty_port *port = &info->port;
 	speed_t baud;
 	unsigned long sl_flags;
-	unsigned int flags;
+	unsigned int flags, close_delay, closing_wait;
 	int retval = 0;
 
 	if (tty->index == MXSER_PORTS)
@@ -1255,9 +1262,14 @@ static int mxser_set_serial_info(struct tty_struct *tty,
 
 	flags = port->flags & ASYNC_SPD_MASK;
 
+	close_delay = msecs_to_jiffies(ss->close_delay * 10);
+	closing_wait = ss->closing_wait;
+	if (closing_wait != ASYNC_CLOSING_WAIT_NONE)
+		closing_wait = msecs_to_jiffies(closing_wait * 10);
+
 	if (!capable(CAP_SYS_ADMIN)) {
 		if ((ss->baud_base != info->baud_base) ||
-				(ss->close_delay != info->port.close_delay) ||
+				(close_delay != info->port.close_delay) ||
 				((ss->flags & ~ASYNC_USR_MASK) != (info->port.flags & ~ASYNC_USR_MASK))) {
 			mutex_unlock(&port->mutex);
 			return -EPERM;
@@ -1271,8 +1283,8 @@ static int mxser_set_serial_info(struct tty_struct *tty,
 		 */
 		port->flags = ((port->flags & ~ASYNC_FLAGS) |
 				(ss->flags & ASYNC_FLAGS));
-		port->close_delay = ss->close_delay * HZ / 100;
-		port->closing_wait = ss->closing_wait * HZ / 100;
+		port->close_delay = close_delay;
+		port->closing_wait = closing_wait;
 		if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST &&
 				(ss->baud_base != info->baud_base ||
 				ss->custom_divisor !=