[PATCH] spinlock.h cleanup

 - cleanup #defines: I do not follow the rationale behind the
   odd line-wrapped defines at the beginning of the file.  If
   we have to use multiple lines, then we might as well do so
   cleanly and according to normal practice...

 - Remove a level of indirection: do not have spin_lock_foo
   use spin_lock - just explicitly call what is needed.

 - we do not need to define the spin_lock functions twice, once
   for CONFIG_PREEMPT and once for !CONFIG_PREEMPT.  Defining
   them once with the preempt macros will optimize away fine.

 - cleanup preempt.h too

 - other misc. cleanup, improved comments, reordering, etc.

include/linux/preempt.h

 #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>
 
 #define preempt_count()	(current_thread_info()->preempt_count)
@@ -31,17 +36,16 @@ do { \
 	barrier(); \
 } while (0)
 
-#define preempt_enable() \
+#define preempt_check_resched() \
 do { \
-	preempt_enable_no_resched(); \
 	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
 		preempt_schedule(); \
 } while (0)
 
-#define preempt_check_resched() \
+#define preempt_enable() \
 do { \
-	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
-		preempt_schedule(); \
+	preempt_enable_no_resched(); \
+	preempt_check_resched(); \
 } while (0)
 
 #define inc_preempt_count_non_preempt()	do { } while (0)
@@ -50,7 +54,7 @@ do { \
 #else
 
 #define preempt_disable()		do { } while (0)
-#define preempt_enable_no_resched()	do {} while(0)
+#define preempt_enable_no_resched()	do { } while (0)
 #define preempt_enable()		do { } while (0)
 #define preempt_check_resched()		do { } while (0)