tty: Redo current tty locking

Currently it is sometimes locked by the tty mutex and sometimes by the
sighand lock. The latter is in fact correct and now we can hand back referenced
objects we can fix this up without problems around sleeping functions.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index 3ef5425d0eb8..84fbc90480dc 100644
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -431,6 +431,7 @@ fs3270_open(struct inode *inode, struct file *filp)
                 tty = get_current_tty();
                 if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
                         tty_kref_put(tty);
+                        mutex_unlock(&tty_mutex);
                         rc = -ENODEV;
                         goto out;
                 }