kvm tools: Add rwlock wrapper

Adds a rwlock wrapper which like the mutex wrapper makes rwlock calls
similar to their kernel counterparts.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/include/kvm/rwsem.h b/tools/kvm/include/kvm/rwsem.h
new file mode 100644 (file)
index 0000000..75a22f8
--- /dev/null
+++ b/tools/kvm/include/kvm/rwsem.h
@@ -0,0 +1,39 @@
+#ifndef KVM__RWSEM_H
+#define KVM__RWSEM_H
+
+#include <pthread.h>
+
+#include "kvm/util.h"
+
+/*
+ * Kernel-alike rwsem API - to make it easier for kernel developers
+ * to write user-space code! :-)
+ */
+
+#define DECLARE_RWSEM(sem) pthread_rwlock_t sem = PTHREAD_RWLOCK_INITIALIZER
+
+static inline void down_read(pthread_rwlock_t *rwsem)
+{
+       if (pthread_rwlock_rdlock(rwsem) != 0)
+               die("unexpected pthread_rwlock_rdlock() failure!");
+}
+
+static inline void down_write(pthread_rwlock_t *rwsem)
+{
+       if (pthread_rwlock_wrlock(rwsem) != 0)
+               die("unexpected pthread_rwlock_wrlock() failure!");
+}
+
+static inline void up_read(pthread_rwlock_t *rwsem)
+{
+       if (pthread_rwlock_unlock(rwsem) != 0)
+               die("unexpected pthread_rwlock_unlock() failure!");
+}
+
+static inline void up_write(pthread_rwlock_t *rwsem)
+{
+       if (pthread_rwlock_unlock(rwsem) != 0)
+               die("unexpected pthread_rwlock_unlock() failure!");
+}
+
+#endif /* KVM__RWSEM_H */