briq_panel: BKL pushdown

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/drivers/char/briq_panel.c b/drivers/char/briq_panel.c
index b6f2639..d8cff90 100644 (file)
--- a/drivers/char/briq_panel.c
+++ b/drivers/char/briq_panel.c
@@ -6,6 +6,7 @@
 
 #include <linux/module.h>
 
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
@@ -67,11 +68,15 @@ static void set_led(char state)
 
 static int briq_panel_open(struct inode *ino, struct file *filep)
 {
-       /* enforce single access */
-       if (vfd_is_open)
+       lock_kernel();
+       /* enforce single access, vfd_is_open is protected by BKL */
+       if (vfd_is_open) {
+               unlock_kernel();
                return -EBUSY;
+       }
        vfd_is_open = 1;
 
+       unlock_kernel();
        return 0;
 }