linux-kernel - [PATCH 03/31] riscom8: kill use of lock

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Message-Id: <1275425591-8803-4-git-send-email-arnd@arndb.de>
Date:	Tue,  1 Jun 2010 22:52:43 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Greg KH <gregkh@...e.de>
Cc:	linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Frederic Weisbecker <fweisbec@...il.com>,
	John Kacur <jkacur@...hat.com>, Alan Cox <alan@...ux.intel.com>
Subject: [PATCH 03/31] riscom8: kill use of lock_kernel

From: Alan Cox <alan@...ux.intel.com>

The riscom8 board uses lock_kernel to protect bits of the port setting
ioctl logic. We can use the port mutex for this as the logic is internal
and will also lock set versus open (a locking property that has been lost
somewhere along the way)

Signed-off-by: Alan Cox <alan@...ux.intel.com>
---
 drivers/char/riscom8.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/char/riscom8.c b/drivers/char/riscom8.c
index b02332a..af4de1f 100644
--- a/drivers/char/riscom8.c
+++ b/drivers/char/riscom8.c
@@ -47,7 +47,6 @@
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/tty_flip.h>
-#include <linux/smp_lock.h>
 #include <linux/spinlock.h>
 #include <linux/device.h>
 
@@ -1184,6 +1183,7 @@ static int rc_set_serial_info(struct tty_struct *tty, struct riscom_port *port,
 	if (copy_from_user(&tmp, newinfo, sizeof(tmp)))
 		return -EFAULT;
 
+	mutex_lock(&port->port.mutex);
 	change_speed = ((port->port.flags & ASYNC_SPD_MASK) !=
 			(tmp.flags & ASYNC_SPD_MASK));
 
@@ -1191,8 +1191,10 @@ static int rc_set_serial_info(struct tty_struct *tty, struct riscom_port *port,
 		if ((tmp.close_delay != port->port.close_delay) ||
 		    (tmp.closing_wait != port->port.closing_wait) ||
 		    ((tmp.flags & ~ASYNC_USR_MASK) !=
-		     (port->port.flags & ~ASYNC_USR_MASK)))
+		     (port->port.flags & ~ASYNC_USR_MASK))) {
+			mutex_unlock(&port->port.mutex);
 			return -EPERM;
+		}
 		port->port.flags = ((port->port.flags & ~ASYNC_USR_MASK) |
 			       (tmp.flags & ASYNC_USR_MASK));
 	} else  {
@@ -1208,6 +1210,7 @@ static int rc_set_serial_info(struct tty_struct *tty, struct riscom_port *port,
 		rc_change_speed(tty, bp, port);
 		spin_unlock_irqrestore(&riscom_lock, flags);
 	}
+	mutex_unlock(&port->port.mutex);
 	return 0;
 }
 
@@ -1220,12 +1223,15 @@ static int rc_get_serial_info(struct riscom_port *port,
 	memset(&tmp, 0, sizeof(tmp));
 	tmp.type = PORT_CIRRUS;
 	tmp.line = port - rc_port;
+
+	mutex_lock(&port->port.mutex);
 	tmp.port = bp->base;
 	tmp.irq  = bp->irq;
 	tmp.flags = port->port.flags;
 	tmp.baud_base = (RC_OSCFREQ + CD180_TPC/2) / CD180_TPC;
 	tmp.close_delay = port->port.close_delay * HZ/100;
 	tmp.closing_wait = port->port.closing_wait * HZ/100;
+	mutex_unlock(&port->port.mutex);
 	tmp.xmit_fifo_size = CD180_NFIFO;
 	return copy_to_user(retinfo, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
@@ -1242,14 +1248,10 @@ static int rc_ioctl(struct tty_struct *tty, struct file *filp,
 
 	switch (cmd) {
 	case TIOCGSERIAL:
-		lock_kernel();
 		retval = rc_get_serial_info(port, argp);
-		unlock_kernel();
 		break;
 	case TIOCSSERIAL:
-		lock_kernel();
 		retval = rc_set_serial_info(tty, port, argp);
-		unlock_kernel();
 		break;
 	default:
 		retval = -ENOIOCTLCMD;
-- 
1.7.0.4

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