lockable: replaced locks with lock guard macros where appropriate

- ran regexp "qemu_mutex_lock\(.*\).*\n.*if" to find targets
- replaced result with QEMU_LOCK_GUARD if all unlocks at function end
- replaced result with WITH_QEMU_LOCK_GUARD if unlock not at end

Signed-off-by: Daniel Brodsky <dnbrdsky@gmail.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-id: 20200404042108.389635-3-dnbrdsky@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

util/rcu.c

@@ -31,6 +31,7 @@
 #include "qemu/atomic.h"
 #include "qemu/thread.h"
 #include "qemu/main-loop.h"
+#include "qemu/lockable.h"
 #if defined(CONFIG_MALLOC_TRIM)
 #include <malloc.h>
 #endif
@@ -141,14 +142,14 @@ static void wait_for_readers(void)
 
 void synchronize_rcu(void)
 {
-    qemu_mutex_lock(&rcu_sync_lock);
+    QEMU_LOCK_GUARD(&rcu_sync_lock);
 
     /* Write RCU-protected pointers before reading p_rcu_reader->ctr.
      * Pairs with smp_mb_placeholder() in rcu_read_lock().
      */
     smp_mb_global();
 
-    qemu_mutex_lock(&rcu_registry_lock);
+    QEMU_LOCK_GUARD(&rcu_registry_lock);
     if (!QLIST_EMPTY(&registry)) {
         /* In either case, the atomic_mb_set below blocks stores that free
          * old RCU-protected pointers.
@@ -169,9 +170,6 @@ void synchronize_rcu(void)
 
         wait_for_readers();
     }
-
-    qemu_mutex_unlock(&rcu_registry_lock);
-    qemu_mutex_unlock(&rcu_sync_lock);
 }