1 files changed, 65 insertions, 0 deletions
diff --git a/include/linux/smp_lock.h b/include/linux/smp_lock.h
new file mode 100644
index 00000000000..2ea1dd1ba21
--- /dev/null
+++ b/include/linux/smp_lock.h
@@ -0,0 +1,65 @@
+#ifndef __LINUX_SMPLOCK_H
+#define __LINUX_SMPLOCK_H
+
+#ifdef CONFIG_LOCK_KERNEL
+#include <linux/sched.h>
+
+#define kernel_locked()		(current->lock_depth >= 0)
+
+extern int __lockfunc __reacquire_kernel_lock(void);
+extern void __lockfunc __release_kernel_lock(void);
+
+/*
+ * Release/re-acquire global kernel lock for the scheduler
+ */
+#define release_kernel_lock(tsk) do { 		\
+	if (unlikely((tsk)->lock_depth >= 0))	\
+		__release_kernel_lock();	\
+} while (0)
+
+static inline int reacquire_kernel_lock(struct task_struct *task)
+{
+	if (unlikely(task->lock_depth >= 0))
+		return __reacquire_kernel_lock();
+	return 0;
+}
+
+extern void __lockfunc
+_lock_kernel(const char *func, const char *file, int line)
+__acquires(kernel_lock);
+
+extern void __lockfunc
+_unlock_kernel(const char *func, const char *file, int line)
+__releases(kernel_lock);
+
+#define lock_kernel() do {					\
+	_lock_kernel(__func__, __FILE__, __LINE__);		\
+} while (0)
+
+#define unlock_kernel()	do {					\
+	_unlock_kernel(__func__, __FILE__, __LINE__);		\
+} while (0)
+
+/*
+ * Various legacy drivers don't really need the BKL in a specific
+ * function, but they *do* need to know that the BKL became available.
+ * This function just avoids wrapping a bunch of lock/unlock pairs
+ * around code which doesn't really need it.
+ */
+static inline void cycle_kernel_lock(void)
+{
+	lock_kernel();
+	unlock_kernel();
+}
+
+#else
+
+#define lock_kernel()
+#define unlock_kernel()
+#define release_kernel_lock(task)		do { } while(0)
+#define cycle_kernel_lock()			do { } while(0)
+#define reacquire_kernel_lock(task)		0
+#define kernel_locked()				1
+
+#endif /* CONFIG_LOCK_KERNEL */
+#endif /* __LINUX_SMPLOCK_H */