watchdog: Remove BKL from rio watchdog driver

cycle_kernel_lock() was added with the BKL pushdown. The rio driver
indeed needs that because riowd_device is initialized after
misc_register(). So an open(), write/ioctl() which happens to get
between misc_register returning and riowd_device initialization would
dereference a NULL pointer.

Move riowd_device initialization before misc_register() and get rid of
cycle_kernel_lock().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/watchdog/riowd.c b/drivers/watchdog/riowd.c
index d3c824dc23588b668096cd368efec6755cbbb9af..c14ae867690356de79612e308b75512d2432becc 100644 (file)
--- a/drivers/watchdog/riowd.c
+++ b/drivers/watchdog/riowd.c
@@ -10,7 +10,6 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/miscdevice.h>
-#include <linux/smp_lock.h>
 #include <linux/watchdog.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -75,7 +74,6 @@ static void riowd_writereg(struct riowd *p, u8 val, int index)
 
 static int riowd_open(struct inode *inode, struct file *filp)
 {
-       cycle_kernel_lock();
        nonseekable_open(inode, filp);
        return 0;
 }
@@ -194,6 +192,8 @@ static int __devinit riowd_probe(struct of_device *op,
                printk(KERN_ERR PFX "Cannot map registers.\n");
                goto out_free;
        }
+       /* Make miscdev useable right away */
+       riowd_device = p;
 
        err = misc_register(&riowd_miscdev);
        if (err) {
@@ -205,10 +205,10 @@ static int __devinit riowd_probe(struct of_device *op,
               "regs at %p\n", riowd_timeout, p->regs);
 
        dev_set_drvdata(&op->dev, p);
-       riowd_device = p;
        return 0;
 
 out_iounmap:
+       riowd_device = NULL;
        of_iounmap(&op->resource[0], p->regs, 2);
 
 out_free: