tty: Move tty_write_message out of kernel/printk

This is pure tty code so put it in the tty layer where it can be with the
locking relevant material it uses

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

drivers/char/tty_io.c

@@ -1081,6 +1081,31 @@ static inline ssize_t do_tty_write(
 	return ret;
 }
 
+/**
+ * tty_write_message - write a message to a certain tty, not just the console.
+ * @tty: the destination tty_struct
+ * @msg: the message to write
+ *
+ * This is used for messages that need to be redirected to a specific tty.
+ * We don't put it into the syslog queue right now maybe in the future if
+ * really needed.
+ *
+ * We must still hold the BKL and test the CLOSING flag for the moment.
+ */
+
+void tty_write_message(struct tty_struct *tty, char *msg)
+{
+	lock_kernel();
+	if (tty) {
+		mutex_lock(&tty->atomic_write_lock);
+		if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
+			tty->ops->write(tty, msg, strlen(msg));
+		tty_write_unlock(tty);
+	}
+	unlock_kernel();
+	return;
+}
+
 
 /**
  *	tty_write		-	write method for tty device file

kernel/printk.c

@@ -1291,22 +1291,6 @@ static int __init disable_boot_consoles(void)
 }
 late_initcall(disable_boot_consoles);
 
-/**
- * tty_write_message - write a message to a certain tty, not just the console.
- * @tty: the destination tty_struct
- * @msg: the message to write
- *
- * This is used for messages that need to be redirected to a specific tty.
- * We don't put it into the syslog queue right now maybe in the future if
- * really needed.
- */
-void tty_write_message(struct tty_struct *tty, char *msg)
-{
-	if (tty && tty->ops->write)
-		tty->ops->write(tty, msg, strlen(msg));
-	return;
-}
-
 #if defined CONFIG_PRINTK
 
 /*