1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/char/dtlk.c b/drivers/char/dtlk.c
index abde6ddefe69..6b900b297cc6 100644
--- a/drivers/char/dtlk.c
+++ b/drivers/char/dtlk.c
@@ -56,6 +56,7 @@
 #include <linux/errno.h>        /* for -EBUSY */
 #include <linux/ioport.h>       /* for request_region */
 #include <linux/delay.h>        /* for loops_per_jiffy */
+#include <linux/smp_lock.h>     /* cycle_kernel_lock() */
 #include <asm/io.h>             /* for inb_p, outb_p, inb, outb, etc. */
 #include <asm/uaccess.h>        /* for get_user, etc. */
 #include <linux/wait.h>         /* for wait_queue */
@@ -288,10 +289,12 @@ static int dtlk_ioctl(struct inode *inode,
         }
 }
 
+/* Note that nobody ever sets dtlk_busy... */
 static int dtlk_open(struct inode *inode, struct file *file)
 {
         TRACE_TEXT("(dtlk_open");
 
+        cycle_kernel_lock();
         nonseekable_open(inode, file);
         switch (iminor(inode)) {
         case DTLK_MINOR: