Convert SpinLock* macros to static inline functions.

This is preparatory work for a proposed follow-up commit that would
add assertions to these functions.

Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/aZX2oUcKf7IzHnnK%40nathan
Discussion: https://postgr.es/m/20200617183354.pm3biu3zbmo2pktq%40alap3.anarazel.de

diff --git a/src/include/storage/spin.h b/src/include/storage/spin.h
index 78c95ae538bc8542e959ba6114cf4ef1fd09ec73..9cf6adb671a860820620938c90b7e0155476e240 100644 (file)
--- a/src/include/storage/spin.h
+++ b/src/include/storage/spin.h
@@ -5,7 +5,7 @@
  *
  *
  *     The interface to spinlocks is defined by the typedef "slock_t" and
- *     these macros:
+ *     these functions:
  *
  *     void SpinLockInit(volatile slock_t *lock)
  *             Initialize a spinlock (to the unlocked state).
@@ -18,9 +18,6 @@
  *     void SpinLockRelease(volatile slock_t *lock)
  *             Unlock a previously acquired lock.
  *
- *     Callers must beware that the macro argument may be evaluated multiple
- *     times!
- *
  *     Load and store operations in calling code are guaranteed not to be
  *     reordered with respect to these operations, because they include a
  *     compiler barrier.  (Before PostgreSQL 9.5, callers needed to use a
@@ -29,9 +26,9 @@
  *     Keep in mind the coding rule that spinlocks must not be held for more
  *     than a few instructions.  In particular, we assume it is not possible
  *     for a CHECK_FOR_INTERRUPTS() to occur while holding a spinlock, and so
- *     it is not necessary to do HOLD/RESUME_INTERRUPTS() in these macros.
+ *     it is not necessary to do HOLD/RESUME_INTERRUPTS() in these functions.
  *
- *     These macros are implemented in terms of hardware-dependent macros
+ *     These functions are implemented in terms of hardware-dependent macros
  *     supplied by s_lock.h.  There is not currently any extra functionality
  *     added by this header, but there has been in the past and may someday
  *     be again.
@@ -49,11 +46,22 @@
 
 #include "storage/s_lock.h"
 
+static inline void
+SpinLockInit(volatile slock_t *lock)
+{
+       S_INIT_LOCK(lock);
+}
 
-#define SpinLockInit(lock)     S_INIT_LOCK(lock)
-
-#define SpinLockAcquire(lock) S_LOCK(lock)
+static inline void
+SpinLockAcquire(volatile slock_t *lock)
+{
+       S_LOCK(lock);
+}
 
-#define SpinLockRelease(lock) S_UNLOCK(lock)
+static inline void
+SpinLockRelease(volatile slock_t *lock)
+{
+       S_UNLOCK(lock);
+}
 
 #endif                                                 /* SPIN_H */