---

yaml
---
r: 207915
b: refs/heads/master
c: b07471f
h: refs/heads/master
i:
  207913: 6609761
  207911: 5ed1f2d
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ddcd9fb66ae7f448b517242c10a31d4e17bcad45
+refs/heads/master: b07471fa51358ce64cc25e1501544502362e4404

trunk/drivers/char/Makefile

@@ -9,6 +9,7 @@ FONTMAPFILE = cp437.uni
 
 obj-y	 += mem.o random.o tty_io.o n_tty.o tty_ioctl.o tty_ldisc.o tty_buffer.o tty_port.o
 
+obj-y				+= tty_mutex.o
 obj-$(CONFIG_LEGACY_PTYS)	+= pty.o
 obj-$(CONFIG_UNIX98_PTYS)	+= pty.o
 obj-y				+= misc.o

trunk/drivers/char/tty_mutex.c

@@ -0,0 +1,47 @@
+/*
+ * drivers/char/tty_lock.c
+ */
+#include <linux/tty.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/semaphore.h>
+#include <linux/sched.h>
+
+/*
+ * The 'big tty mutex'
+ *
+ * This mutex is taken and released by tty_lock() and tty_unlock(),
+ * replacing the older big kernel lock.
+ * It can no longer be taken recursively, and does not get
+ * released implicitly while sleeping.
+ *
+ * Don't use in new code.
+ */
+static DEFINE_MUTEX(big_tty_mutex);
+struct task_struct *__big_tty_mutex_owner;
+EXPORT_SYMBOL_GPL(__big_tty_mutex_owner);
+
+/*
+ * Getting the big tty mutex.
+ */
+void __lockfunc tty_lock(void)
+{
+	struct task_struct *task = current;
+
+	WARN_ON(__big_tty_mutex_owner == task);
+
+	mutex_lock(&big_tty_mutex);
+	__big_tty_mutex_owner = task;
+}
+EXPORT_SYMBOL(tty_lock);
+
+void __lockfunc tty_unlock(void)
+{
+	struct task_struct *task = current;
+
+	WARN_ON(__big_tty_mutex_owner != task);
+	__big_tty_mutex_owner = NULL;
+
+	mutex_unlock(&big_tty_mutex);
+}
+EXPORT_SYMBOL(tty_unlock);

trunk/include/linux/tty.h

@@ -578,20 +578,12 @@ extern int vt_ioctl(struct tty_struct *tty, struct file *file,
 extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file,
 		     unsigned int cmd, unsigned long arg);
 
+/* tty_mutex.c */
 /* functions for preparation of BKL removal */
-static inline void tty_lock(void) __acquires(kernel_lock)
-{
-#ifdef CONFIG_LOCK_KERNEL
-	/* kernel_locked is 1 for !CONFIG_LOCK_KERNEL */
-	WARN_ON(kernel_locked());
-#endif
-	lock_kernel();
-}
-static inline void tty_unlock(void) __releases(kernel_lock)
-{
-	unlock_kernel();
-}
-#define tty_locked()		(kernel_locked())
+extern void __lockfunc tty_lock(void) __acquires(tty_lock);
+extern void __lockfunc tty_unlock(void) __releases(tty_lock);
+extern struct task_struct *__big_tty_mutex_owner;
+#define tty_locked()		(current == __big_tty_mutex_owner)
 
 /*
  * wait_event_interruptible_tty -- wait for a condition with the tty lock held