[patch] stricter type-checking rwlock primitives, x86

[Ingo Molnar <mingo@elte.hu>]

[patch respun with s/trylock_test/can_lock/]
--

turn x86 rwlock macros into inline functions, to get stricter
type-checking. Test-built/booted on x86. (patch comes after all
previous spinlock patches.)

	Ingo

Signed-off-by: Ingo Molnar <mingo@elte.hu>

--- linux/include/asm-i386/spinlock.h.orig
+++ linux/include/asm-i386/spinlock.h
@@ -198,21 +198,33 @@ typedef struct {
 
 #define RW_LOCK_UNLOCKED (rwlock_t) { RW_LOCK_BIAS RWLOCK_MAGIC_INIT }
 
-#define rwlock_init(x)	do { *(x) = RW_LOCK_UNLOCKED; } while(0)
+static inline void rwlock_init(rwlock_t *rw)
+{
+	*rw = RW_LOCK_UNLOCKED;
+}
 
-#define rwlock_is_locked(x) ((x)->lock != RW_LOCK_BIAS)
+static inline int rwlock_is_locked(rwlock_t *rw)
+{
+	return rw->lock != RW_LOCK_BIAS;
+}
 
 /**
  * read_can_lock - would read_trylock() succeed?
  * @lock: the rwlock in question.
  */
-#define read_can_lock(x) (atomic_read((atomic_t *)&(x)->lock) > 0)
+static inline int read_can_lock(rwlock_t *rw)
+{
+	return atomic_read((atomic_t *)&rw->lock) > 0;
+}
 
 /**
  * write_can_lock - would write_trylock() succeed?
  * @lock: the rwlock in question.
  */
-#define write_can_lock(x) ((x)->lock = RW_LOCK_BIAS)
+static inline int write_can_lock(rwlock_t *rw)
+{
+	return atomic_read((atomic_t *)&rw->lock) = RW_LOCK_BIAS;
+}
 
 /*
  * On x86, we implement read-write locks as a 32-bit counter
@@ -241,8 +253,16 @@ static inline void _raw_write_lock(rwloc
 	__build_write_lock(rw, "__write_lock_failed");
 }
 
-#define _raw_read_unlock(rw)		asm volatile("lock ; incl %0" :"=m" ((rw)->lock) : : "memory")
-#define _raw_write_unlock(rw)	asm volatile("lock ; addl $" RW_LOCK_BIAS_STR ",%0":"=m" ((rw)->lock) : : "memory")
+static inline void _raw_read_unlock(rwlock_t *rw)
+{
+	asm volatile("lock ; incl %0" :"=m" (rw->lock) : : "memory");
+}
+
+static inline void _raw_write_unlock(rwlock_t *rw)
+{
+	asm volatile("lock ; addl $" RW_LOCK_BIAS_STR
+				",%0":"=m" (rw->lock) : : "memory");
+}
 
 static inline int _raw_read_trylock(rwlock_t *lock)
 {