tty: localise the lock

The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.

This contains pieces folded in from the fixes made to the original patches

| From: Geert Uytterhoeven <geert@linux-m68k.org>	(fix m68k)
| From: Paul Gortmaker <paul.gortmaker@windriver.com>	(fix cris)
| From: Jiri Kosina <jkosina@suze.cz>			(lockdep)
| From: Eric Dumazet <eric.dumazet@gmail.com>		(lockdep)

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 14 insertions, 9 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index a39e72325e78..acca24bf06a7 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -268,6 +268,7 @@ struct tty_struct {
         struct mutex ldisc_mutex;
         struct tty_ldisc *ldisc;
 
+        struct mutex legacy_mutex;
         struct mutex termios_mutex;
         spinlock_t ctrl_lock;
         /* Termios values are protected by the termios mutex */
@@ -609,8 +610,12 @@ extern long vt_compat_ioctl(struct tty_struct *tty,
 
 /* tty_mutex.c */
 /* functions for preparation of BKL removal */
-extern void __lockfunc tty_lock(void) __acquires(tty_lock);
-extern void __lockfunc tty_unlock(void) __releases(tty_lock);
+extern void __lockfunc tty_lock(struct tty_struct *tty);
+extern void __lockfunc tty_unlock(struct tty_struct *tty);
+extern void __lockfunc tty_lock_pair(struct tty_struct *tty,
+                                struct tty_struct *tty2);
+extern void __lockfunc tty_unlock_pair(struct tty_struct *tty,
+                                struct tty_struct *tty2);
 
 /*
  * this shall be called only from where BTM is held (like close)
@@ -625,9 +630,9 @@ extern void __lockfunc tty_unlock(void) __releases(tty_lock);
 static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
                 long timeout)
 {
-        tty_unlock(); /* tty->ops->close holds the BTM, drop it while waiting */
+        tty_unlock(tty); /* tty->ops->close holds the BTM, drop it while waiting */
         tty_wait_until_sent(tty, timeout);
-        tty_lock();
+        tty_lock(tty);
 }
 
 /*
@@ -642,16 +647,16 @@ static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
  *
  * Do not use in new code.
  */
-#define wait_event_interruptible_tty(wq, condition)                     \
+#define wait_event_interruptible_tty(tty, wq, condition)                \
 ({                                                                      \
         int __ret = 0;                                                  \
         if (!(condition)) {                                             \
-                __wait_event_interruptible_tty(wq, condition, __ret);   \
+                __wait_event_interruptible_tty(tty, wq, condition, __ret);      \
         }                                                               \
         __ret;                                                          \
 })
 
-#define __wait_event_interruptible_tty(wq, condition, ret)              \
+#define __wait_event_interruptible_tty(tty, wq, condition, ret)         \
 do {                                                                    \
         DEFINE_WAIT(__wait);                                            \
                                                                         \
@@ -660,9 +665,9 @@ do {									\
                 if (condition)                                          \
                         break;                                          \
                 if (!signal_pending(current)) {                         \
-                        tty_unlock();                                   \
+                        tty_unlock(tty);                                        \
                         schedule();                                     \
-                        tty_lock();                                     \
+                        tty_lock(tty);                                  \
                         continue;                                       \
                 }                                                       \
                 ret = -ERESTARTSYS;                                     \