tty: refactor TIOCSSERIAL handling

Factor out the deprecated serial flags handling and tty-operation check
shared with the compat TIOCSSERIAL handler.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-6-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index e00efd2..36e6b28 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2624,23 +2624,31 @@ static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
        return 0;
 }
 
-static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
+static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
 {
        char comm[TASK_COMM_LEN];
-       struct serial_struct v;
        int flags;
 
-       if (copy_from_user(&v, ss, sizeof(*ss)))
-               return -EFAULT;
-
-       flags = v.flags & ASYNC_DEPRECATED;
+       flags = ss->flags & ASYNC_DEPRECATED;
 
        if (flags)
                pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
                                __func__, get_task_comm(comm, current), flags);
+
        if (!tty->ops->set_serial)
                return -ENOTTY;
-       return tty->ops->set_serial(tty, &v);
+
+       return tty->ops->set_serial(tty, ss);
+}
+
+static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
+{
+       struct serial_struct v;
+
+       if (copy_from_user(&v, ss, sizeof(*ss)))
+               return -EFAULT;
+
+       return tty_set_serial(tty, &v);
 }
 
 static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
@@ -2838,10 +2846,8 @@ struct serial_struct32 {
 static int compat_tty_tiocsserial(struct tty_struct *tty,
                struct serial_struct32 __user *ss)
 {
-       char comm[TASK_COMM_LEN];
        struct serial_struct32 v32;
        struct serial_struct v;
-       int flags;
 
        if (copy_from_user(&v32, ss, sizeof(*ss)))
                return -EFAULT;
@@ -2852,14 +2858,7 @@ static int compat_tty_tiocsserial(struct tty_struct *tty,
        v.port_high = v32.port_high;
        v.iomap_base = 0;
 
-       flags = v.flags & ASYNC_DEPRECATED;
-
-       if (flags)
-               pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
-                               __func__, get_task_comm(comm, current), flags);
-       if (!tty->ops->set_serial)
-               return -ENOTTY;
-       return tty->ops->set_serial(tty, &v);
+       return tty_set_serial(tty, &v);
 }
 
 static int compat_tty_tiocgserial(struct tty_struct *tty,