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-v32/drivers/sync_serial.c b/arch/cris/arch-v32/drivers/sync_serial.c
index ca248f3adb80..a01ae9f3b814 100644
--- a/arch/cris/arch-v32/drivers/sync_serial.c
+++ b/arch/cris/arch-v32/drivers/sync_serial.c
@@ -13,7 +13,7 @@
 #include <linux/errno.h>
 #include <linux/major.h>
 #include <linux/sched.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/interrupt.h>
 #include <linux/poll.h>
 #include <linux/init.h>
@@ -145,6 +145,7 @@ typedef struct sync_port
 	spinlock_t lock;
 } 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);
@@ -434,7 +435,7 @@ static int sync_serial_open(struct inode *inode, struct file *file)
 	reg_dma_rw_cfg cfg = {.en = regk_dma_yes};
 	reg_dma_rw_intr_mask intr_mask = {.data = regk_dma_yes};
 
-	lock_kernel();
+	mutex_lock(&sync_serial_mutex);
 	DEBUG(printk(KERN_DEBUG "Open sync serial port %d\n", dev));
 
 	if (dev < 0 || dev >= NBR_PORTS || !ports[dev].enabled)
@@ -583,7 +584,7 @@ static int sync_serial_open(struct inode *inode, struct file *file)
 	port->busy++;
 	ret = 0;
 out:
-	unlock_kernel();
+	mutex_unlock(&sync_serial_mutex);
 	return ret;
 }
 
@@ -966,9 +967,9 @@ 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;
 }