cris: autoconvert trivial BKL users

All uses of the big kernel lock in the cris architecture
are for ioctl and open functions of character device drivers,
which can be trivially converted to a per-driver mutex.

Most of these are probably unnecessary, so it may make sense
to audit them and eventually remove the extra mutex introduced
by this patch.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: linux-cris-kernel@axis.com

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/cris/arch-v10/drivers/sync_serial.c b/arch/cris/arch-v10/drivers/sync_serial.c
index ee2dd4323daf..3d9fa074a941 100644
--- a/arch/cris/arch-v10/drivers/sync_serial.c
+++ b/arch/cris/arch-v10/drivers/sync_serial.c
@@ -20,7 +20,7 @@
 #include <linux/interrupt.h>
 #include <linux/poll.h>
 #include <linux/init.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/timer.h>
 #include <asm/irq.h>
 #include <asm/dma.h>
@@ -149,6 +149,7 @@ struct sync_port {
 };
 
 
+static DEFINE_MUTEX(sync_serial_mutex);
 static int etrax_sync_serial_init(void);
 static void initialize_port(int portnbr);
 static inline int sync_data_avail(struct sync_port *port);
@@ -445,7 +446,7 @@ static int sync_serial_open(struct inode *inode, struct file *file)
 	int mode;
 	int err = -EBUSY;
 
-	lock_kernel();
+	mutex_lock(&sync_serial_mutex);
 	DEBUG(printk(KERN_DEBUG "Open sync serial port %d\n", dev));
 
 	if (dev < 0 || dev >= NUMBER_OF_PORTS || !ports[dev].enabled) {
@@ -626,7 +627,7 @@ static int sync_serial_open(struct inode *inode, struct file *file)
 	ret = 0;
 	
 out:
-	unlock_kernel();
+	mutex_unlock(&sync_serial_mutex);
 	return ret;
 }
 
@@ -961,9 +962,9 @@ static long sync_serial_ioctl(struct file *file,
 {
 	long ret;
 
-	lock_kernel();
+	mutex_lock(&sync_serial_mutex);
 	ret = sync_serial_ioctl_unlocked(file, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&sync_serial_mutex);
 
 	return ret;
 }