Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

include/linux/preempt.h

@@ -0,0 +1,62 @@
+#ifndef __LINUX_PREEMPT_H
+#define __LINUX_PREEMPT_H
+
+/*
+ * include/linux/preempt.h - macros for accessing and manipulating
+ * preempt_count (used for kernel preemption, interrupt count, etc.)
+ */
+
+#include <linux/config.h>
+#include <linux/linkage.h>
+
+#ifdef CONFIG_DEBUG_PREEMPT
+  extern void fastcall add_preempt_count(int val);
+  extern void fastcall sub_preempt_count(int val);
+#else
+# define add_preempt_count(val)	do { preempt_count() += (val); } while (0)
+# define sub_preempt_count(val)	do { preempt_count() -= (val); } while (0)
+#endif
+
+#define inc_preempt_count() add_preempt_count(1)
+#define dec_preempt_count() sub_preempt_count(1)
+
+#define preempt_count()	(current_thread_info()->preempt_count)
+
+#ifdef CONFIG_PREEMPT
+
+asmlinkage void preempt_schedule(void);
+
+#define preempt_disable() \
+do { \
+	inc_preempt_count(); \
+	barrier(); \
+} while (0)
+
+#define preempt_enable_no_resched() \
+do { \
+	barrier(); \
+	dec_preempt_count(); \
+} while (0)
+
+#define preempt_check_resched() \
+do { \
+	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
+		preempt_schedule(); \
+} while (0)
+
+#define preempt_enable() \
+do { \
+	preempt_enable_no_resched(); \
+	preempt_check_resched(); \
+} while (0)
+
+#else
+
+#define preempt_disable()		do { } while (0)
+#define preempt_enable_no_resched()	do { } while (0)
+#define preempt_enable()		do { } while (0)
+#define preempt_check_resched()		do { } while (0)
+
+#endif
+
+#endif /* __LINUX_PREEMPT_H */