tty_audit: make tty pointers in exposed functions const

Both tty_audit_add_data() and tty_audit_tiocsti() need only to read from
the tty struct, so make the tty parameters of them both const. This
aids the compiler a bit.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230621101611.10580-6-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty.h

@@ -99,14 +99,15 @@ extern int tty_ldisc_autoload;
 
 /* tty_audit.c */
 #ifdef CONFIG_AUDIT
-void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size);
-void tty_audit_tiocsti(struct tty_struct *tty, char ch);
+void tty_audit_add_data(const struct tty_struct *tty, const void *data,
+			size_t size);
+void tty_audit_tiocsti(const struct tty_struct *tty, char ch);
 #else
-static inline void tty_audit_add_data(struct tty_struct *tty, const void *data,
-				      size_t size)
+static inline void tty_audit_add_data(const struct tty_struct *tty,
+				      const void *data, size_t size)
 {
 }
-static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
+static inline void tty_audit_tiocsti(const struct tty_struct *tty, char ch)
 {
 }
 #endif

drivers/tty/tty_audit.c

@@ -134,7 +134,7 @@ void tty_audit_fork(struct signal_struct *sig)
 /*
  *	tty_audit_tiocsti	-	Log TIOCSTI
  */
-void tty_audit_tiocsti(struct tty_struct *tty, char ch)
+void tty_audit_tiocsti(const struct tty_struct *tty, char ch)
 {
 	dev_t dev;
 
@@ -199,7 +199,8 @@ static struct tty_audit_buf *tty_audit_buf_get(void)
  *
  *	Audit @data of @size from @tty, if necessary.
  */
-void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size)
+void tty_audit_add_data(const struct tty_struct *tty, const void *data,
+			size_t size)
 {
 	struct tty_audit_buf *buf;
 	unsigned int audit_tty;