tlckl: BKL pushdown

Put explicit lock_kernel calls into tlclk_open()

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/char/tlclk.c b/drivers/char/tlclk.c
index 35e58030d296..8f2284be68e1 100644
--- a/drivers/char/tlclk.c
+++ b/drivers/char/tlclk.c
@@ -36,6 +36,7 @@
 #include <linux/ioport.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 #include <linux/timer.h>
 #include <linux/sysfs.h>
 #include <linux/device.h>
@@ -204,11 +205,14 @@ static int tlclk_open(struct inode *inode, struct file *filp)
 {
         int result;
 
-        if (test_and_set_bit(0, &useflags))
-                return -EBUSY;
+        lock_kernel();
+        if (test_and_set_bit(0, &useflags)) {
+                result = -EBUSY;
                 /* this legacy device is always one per system and it doesn't
                  * know how to handle multiple concurrent clients.
                  */
+                goto out;
+        }
 
         /* Make sure there is no interrupt pending while
          * initialising interrupt handler */
@@ -218,13 +222,14 @@ static int tlclk_open(struct inode *inode, struct file *filp)
          * we can't share this IRQ */
         result = request_irq(telclk_interrupt, &tlclk_interrupt,
                              IRQF_DISABLED, "telco_clock", tlclk_interrupt);
-        if (result == -EBUSY) {
+        if (result == -EBUSY)
                 printk(KERN_ERR "tlclk: Interrupt can't be reserved.\n");
-                return -EBUSY;
-        }
-        inb(TLCLK_REG6);        /* Clear interrupt events */
+        else
+                inb(TLCLK_REG6);        /* Clear interrupt events */
 
-        return 0;
+out:
+        unlock_kernel();
+        return result;
 }
 
 static int tlclk_release(struct inode *inode, struct file *filp)