viocons: BKL locking

For some weird reason I can't ascertain (translation "I think its
broken") the viocons driver calls directly into the n_tty ldisc code even
if another ldisc is in use. It'll probably break if you do that but I'm
just fixing the locking and adding a comment that its horked.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/char/viocons.c b/drivers/char/viocons.c
index 8de6b95aeb84..9319c63dda9a 100644
--- a/drivers/char/viocons.c
+++ b/drivers/char/viocons.c
@@ -704,8 +704,11 @@ static int viotty_ioctl(struct tty_struct *tty, struct file *file,
         case KDSKBLED:
                 return 0;
         }
-
-        return n_tty_ioctl(tty, file, cmd, arg);
+        /* FIXME: WTF is this being called for ??? */
+        lock_kernel();
+        ret =  n_tty_ioctl(tty, file, cmd, arg);
+        unlock_kernel();
+        return ret;
 }
 
 /*