src/spinlock.[hc]: use pthread spinlock

src/spinlock.c

@@ -39,9 +39,8 @@ static inline int fc_futex(int *ptr, int op, int val)
 int fc_spinlock_init(FCSpinlock *lock, int *cond)
 {
 #ifdef OS_LINUX
-    lock->mutex = 0;
     lock->cond = cond;
-    return 0;
+    return pthread_spin_init(&lock->mutex, 0);
 #else
     return init_pthread_lock_cond_pair(&lock->lcp);
 #endif
@@ -58,7 +57,7 @@ void fc_spinlock_destroy(FCSpinlock *lock)
 int fc_spinlock_lock(FCSpinlock *lock)
 {
 #ifdef OS_LINUX
-    return fc_futex(&lock->mutex, FUTEX_LOCK_PI_PRIVATE, 0);
+    return pthread_spin_lock(&lock->mutex);
 #else
     return pthread_mutex_lock(&lock->lcp.lock);
 #endif
@@ -67,7 +66,7 @@ int fc_spinlock_lock(FCSpinlock *lock)
 int fc_spinlock_trylock(FCSpinlock *lock)
 {
 #ifdef OS_LINUX
-    return fc_futex(&lock->mutex, FUTEX_TRYLOCK_PI_PRIVATE, 0);
+    return pthread_spin_trylock(&lock->mutex);
 #else
     return pthread_mutex_trylock(&lock->lcp.lock);
 #endif
@@ -76,7 +75,7 @@ int fc_spinlock_trylock(FCSpinlock *lock)
 int fc_spinlock_unlock(FCSpinlock *lock)
 {
 #ifdef OS_LINUX
-    return fc_futex(&lock->mutex, FUTEX_UNLOCK_PI_PRIVATE, 0);
+    return pthread_spin_unlock(&lock->mutex);
 #else
     return pthread_mutex_unlock(&lock->lcp.lock);
 #endif
@@ -88,11 +87,11 @@ int fc_spinlock_wait(FCSpinlock *lock, const int expected)
     int result;
     int lock_ret;
 
-    if ((result=fc_futex(&lock->mutex, FUTEX_UNLOCK_PI_PRIVATE, 0)) != 0) {
+    if ((result=pthread_spin_unlock(&lock->mutex)) != 0) {
         return result;
     }
     result = fc_futex(lock->cond, FUTEX_WAIT_PRIVATE, expected);
-    lock_ret = fc_futex(&lock->mutex, FUTEX_LOCK_PI_PRIVATE, 0);
+    lock_ret = pthread_spin_lock(&lock->mutex);
     return result == 0 ? lock_ret : result;
 #else
     return pthread_cond_wait(&lock->lcp.cond, &lock->lcp.lock);

src/spinlock.h

@@ -21,7 +21,7 @@
 
 typedef struct fc_spinlock_t {
 #ifdef OS_LINUX
-    int mutex;
+    pthread_spinlock_t mutex;
     int *cond;
 #else
     pthread_lock_cond_pair_t lcp;