tty: move some internal tty lock enums and functions out of tty.h

[ Upstream commit 6c80c0b94b94192d9a34b400f8237703c6475f4d ]

Move the TTY_LOCK_* enums and tty_ldisc lock functions out of the global
tty.h into the local header file to clean things up.

Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20210408125134.3016837-10-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 094fb49a2d0d ("tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH")
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/tty/tty.h

@@ -18,6 +18,32 @@
 #define tty_info_ratelimited(tty, f, ...) \
 		tty_msg(pr_info_ratelimited, tty, f, ##__VA_ARGS__)
 
+/*
+ * Lock subclasses for tty locks
+ *
+ * TTY_LOCK_NORMAL is for normal ttys and master ptys.
+ * TTY_LOCK_SLAVE is for slave ptys only.
+ *
+ * Lock subclasses are necessary for handling nested locking with pty pairs.
+ * tty locks which use nested locking:
+ *
+ * legacy_mutex - Nested tty locks are necessary for releasing pty pairs.
+ *		  The stable lock order is master pty first, then slave pty.
+ * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem.
+ *		   Subclassing this lock enables the slave pty to hold its
+ *		   termios_rwsem when claiming the master tty_buffer lock.
+ * tty_buffer lock - slave ptys can claim nested buffer lock when handling
+ *		     signal chars. The stable lock order is slave pty, then
+ *		     master.
+ */
+enum {
+	TTY_LOCK_NORMAL = 0,
+	TTY_LOCK_SLAVE,
+};
+
+int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout);
+void tty_ldisc_unlock(struct tty_struct *tty);
+
 /* tty_audit.c */
 #ifdef CONFIG_AUDIT
 void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size);

drivers/tty/tty_buffer.c

@@ -17,7 +17,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/ratelimit.h>
-
+#include "tty.h"
 
 #define MIN_TTYB_SIZE	256
 #define TTYB_ALIGN_MASK	255

drivers/tty/tty_mutex.c

@@ -4,6 +4,7 @@
 #include <linux/kallsyms.h>
 #include <linux/semaphore.h>
 #include <linux/sched.h>
+#include "tty.h"
 
 /* Legacy tty mutex glue */
 

include/linux/tty.h

@@ -16,30 +16,6 @@
 #include <linux/llist.h>
 
 
-/*
- * Lock subclasses for tty locks
- *
- * TTY_LOCK_NORMAL is for normal ttys and master ptys.
- * TTY_LOCK_SLAVE is for slave ptys only.
- *
- * Lock subclasses are necessary for handling nested locking with pty pairs.
- * tty locks which use nested locking:
- *
- * legacy_mutex - Nested tty locks are necessary for releasing pty pairs.
- *		  The stable lock order is master pty first, then slave pty.
- * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem.
- *		   Subclassing this lock enables the slave pty to hold its
- *		   termios_rwsem when claiming the master tty_buffer lock.
- * tty_buffer lock - slave ptys can claim nested buffer lock when handling
- *		     signal chars. The stable lock order is slave pty, then
- *		     master.
- */
-
-enum {
-	TTY_LOCK_NORMAL = 0,
-	TTY_LOCK_SLAVE,
-};
-
 /*
  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
  * hardcoded at present.)
@@ -419,8 +395,6 @@ extern const char *tty_name(const struct tty_struct *tty);
 extern struct tty_struct *tty_kopen(dev_t device);
 extern void tty_kclose(struct tty_struct *tty);
 extern int tty_dev_name_to_number(const char *name, dev_t *number);
-extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout);
-extern void tty_ldisc_unlock(struct tty_struct *tty);
 extern ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *);
 #else
 static inline void tty_kref_put(struct tty_struct *tty)