Add a bunch of cycle_kernel_lock() calls

All of the open() functions which don't need the BKL on their face may
still depend on its acquisition to serialize opens against driver
initialization.  So make those functions acquire then release the BKL to be
on the safe side.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index ce19875..f6e6aca 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -66,6 +66,7 @@
 #include <linux/poll.h>
 #include <linux/major.h>
 #include <linux/ppdev.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 
 #define PP_VERSION "ppdev: user-space parallel port driver"
@@ -633,12 +634,12 @@
 	return 0;
 }
 
-/* No BKL needed here: only local resources used */
 static int pp_open (struct inode * inode, struct file * file)
 {
 	unsigned int minor = iminor(inode);
 	struct pp_struct *pp;
 
+	cycle_kernel_lock();
 	if (minor >= PARPORT_MAX)
 		return -ENXIO;