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) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/tty.h

···
 
 /* 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

···
 /*
  *	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;
 
···
  *
  *	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;