tty_io: fasync BKL pushdown

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 9 insertions, 5 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index fd182f2e4a6c..eda27899372c 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2909,15 +2909,16 @@ static int tty_fasync(int fd, struct file *filp, int on)
 {
         struct tty_struct *tty;
         unsigned long flags;
-        int retval;
+        int retval = 0;
 
+        lock_kernel();
         tty = (struct tty_struct *)filp->private_data;
         if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
-                return 0;
+                goto out;
 
         retval = fasync_helper(fd, filp, on, &tty->fasync);
         if (retval <= 0)
-                return retval;
+                goto out;
 
         if (on) {
                 enum pid_type type;
@@ -2935,12 +2936,15 @@ static int tty_fasync(int fd, struct file *filp, int on)
                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                 retval = __f_setown(filp, pid, type, 0);
                 if (retval)
-                        return retval;
+                        goto out;
         } else {
                 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
                         tty->minimum_to_wake = N_TTY_BUF_SIZE;
         }
-        return 0;
+        retval = 0;
+out:
+        unlock_kernel();
+        return retval;
 }
 
 /**