From 1c729ab15a0eeff57aafab704161f8d3663b2854 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 11 Sep 2018 22:01:00 -0400
Subject: [PATCH] moxa: switch to ->[sg]et_serial()

Pointless dead assignments in moxa_set_serial_info() killed off;
they would've been a bug, if not for the fact that user-settable
flags had never been used in that driver.  Bogus from day 1,
though...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/tty/moxa.c | 79 +++++++++++++++++++++++-----------------------
 1 file changed, 40 insertions(+), 39 deletions(-)

diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index 250a19f042d7..3a1a5e0ee93f 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -221,8 +221,8 @@ static int MoxaPortRxQueue(struct moxa_port *);
 static int MoxaPortTxFree(struct moxa_port *);
 static void MoxaPortTxDisable(struct moxa_port *);
 static void MoxaPortTxEnable(struct moxa_port *);
-static int moxa_get_serial_info(struct moxa_port *, struct serial_struct __user *);
-static int moxa_set_serial_info(struct moxa_port *, struct serial_struct __user *);
+static int moxa_get_serial_info(struct tty_struct *, struct serial_struct *);
+static int moxa_set_serial_info(struct tty_struct *, struct serial_struct *);
 static void MoxaSetFifo(struct moxa_port *port, int enable);
 
 /*
@@ -375,16 +375,6 @@ static int moxa_ioctl(struct tty_struct *tty,
 		}
 		break;
 	}
-	case TIOCGSERIAL:
-	        mutex_lock(&ch->port.mutex);
-		ret = moxa_get_serial_info(ch, argp);
-		mutex_unlock(&ch->port.mutex);
-		break;
-	case TIOCSSERIAL:
-	        mutex_lock(&ch->port.mutex);
-		ret = moxa_set_serial_info(ch, argp);
-		mutex_unlock(&ch->port.mutex);
-		break;
 	default:
 		ret = -ENOIOCTLCMD;
 	}
@@ -415,6 +405,8 @@ static const struct tty_operations moxa_ops = {
 	.break_ctl = moxa_break_ctl,
 	.tiocmget = moxa_tiocmget,
 	.tiocmset = moxa_tiocmset,
+	.set_serial = moxa_set_serial_info,
+	.get_serial = moxa_get_serial_info,
 };
 
 static const struct tty_port_operations moxa_port_ops = {
@@ -2034,46 +2026,55 @@ static void MoxaPortTxEnable(struct moxa_port *port)
 	moxafunc(port->tableAddr, FC_SetXonState, Magic_code);
 }
 
-static int moxa_get_serial_info(struct moxa_port *info,
-		struct serial_struct __user *retinfo)
+static int moxa_get_serial_info(struct tty_struct *tty,
+		struct serial_struct *ss)
 {
-	struct serial_struct tmp = {
-		.type = info->type,
-		.line = info->port.tty->index,
-		.flags = info->port.flags,
-		.baud_base = 921600,
-		.close_delay = info->port.close_delay
-	};
-	return copy_to_user(retinfo, &tmp, sizeof(*retinfo)) ? -EFAULT : 0;
+	struct moxa_port *info = tty->driver_data;
+
+	if (tty->index == MAX_PORTS)
+		return -EINVAL;
+	if (!info)
+		return -ENODEV;
+	mutex_lock(&info->port.mutex);
+	ss->type = info->type,
+	ss->line = info->port.tty->index,
+	ss->flags = info->port.flags,
+	ss->baud_base = 921600,
+	ss->close_delay = info->port.close_delay;
+	mutex_unlock(&info->port.mutex);
+	return 0;
 }
 
 
-static int moxa_set_serial_info(struct moxa_port *info,
-		struct serial_struct __user *new_info)
+static int moxa_set_serial_info(struct tty_struct *tty,
+		struct serial_struct *ss)
 {
-	struct serial_struct new_serial;
+	struct moxa_port *info = tty->driver_data;
 
-	if (copy_from_user(&new_serial, new_info, sizeof(new_serial)))
-		return -EFAULT;
+	if (tty->index == MAX_PORTS)
+		return -EINVAL;
+	if (!info)
+		return -ENODEV;
 
-	if (new_serial.irq != 0 || new_serial.port != 0 ||
-			new_serial.custom_divisor != 0 ||
-			new_serial.baud_base != 921600)
+	if (ss->irq != 0 || ss->port != 0 ||
+			ss->custom_divisor != 0 ||
+			ss->baud_base != 921600)
 		return -EPERM;
 
+	mutex_lock(&info->port.mutex);
 	if (!capable(CAP_SYS_ADMIN)) {
-		if (((new_serial.flags & ~ASYNC_USR_MASK) !=
-		     (info->port.flags & ~ASYNC_USR_MASK)))
+		if (((ss->flags & ~ASYNC_USR_MASK) !=
+		     (info->port.flags & ~ASYNC_USR_MASK))) {
+			mutex_unlock(&info->port.mutex);
 			return -EPERM;
-	} else
-		info->port.close_delay = new_serial.close_delay * HZ / 100;
+		}
+	}
+	info->port.close_delay = ss->close_delay * HZ / 100;
 
-	new_serial.flags = (new_serial.flags & ~ASYNC_FLAGS);
-	new_serial.flags |= (info->port.flags & ASYNC_FLAGS);
+	MoxaSetFifo(info, ss->type == PORT_16550A);
 
-	MoxaSetFifo(info, new_serial.type == PORT_16550A);
-
-	info->type = new_serial.type;
+	info->type = ss->type;
+	mutex_unlock(&info->port.mutex);
 	return 0;
 }