1 files changed, 11 insertions, 5 deletions

diff --git a/drivers/isdn/hardware/eicon/divamnt.c b/drivers/isdn/hardware/eicon/divamnt.c
index c90928974249..1e85f743214e 100644
--- a/drivers/isdn/hardware/eicon/divamnt.c
+++ b/drivers/isdn/hardware/eicon/divamnt.c
@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/poll.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 
 #include "platform.h"
@@ -127,14 +128,19 @@ static unsigned int maint_poll(struct file *file, poll_table * wait)
 
 static int maint_open(struct inode *ino, struct file *filep)
 {
+        int ret;
+
+        lock_kernel();
         /* only one open is allowed, so we test
            it atomically */
         if (test_and_set_bit(0, &opened))
-                return (-EBUSY);
-
-        filep->private_data = NULL;
-
-        return nonseekable_open(ino, filep);
+                ret = -EBUSY;
+        else {
+                filep->private_data = NULL;
+                ret = nonseekable_open(ino, filep);
+        }
+        unlock_kernel();
+        return ret;
 }
 
 static int maint_close(struct inode *ino, struct file *filep)