qemu-thread: introduce QemuRecMutex

GRecMutex is new in glib 2.32, so we cannot use it.  Introduce
a recursive mutex in qemu-thread instead, which will be used
instead of RFifoLock.

Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-20-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>

include/qemu/thread-posix.h

@@ -4,6 +4,12 @@
 #include <pthread.h>
 #include <semaphore.h>
 
+typedef QemuMutex QemuRecMutex;
+#define qemu_rec_mutex_destroy qemu_mutex_destroy
+#define qemu_rec_mutex_lock qemu_mutex_lock
+#define qemu_rec_mutex_try_lock qemu_mutex_try_lock
+#define qemu_rec_mutex_unlock qemu_mutex_unlock
+
 struct QemuMutex {
     pthread_mutex_t lock;
 };

include/qemu/thread-win32.h

@@ -8,6 +8,16 @@ struct QemuMutex {
     LONG owner;
 };
 
+typedef struct QemuRecMutex QemuRecMutex;
+struct QemuRecMutex {
+    CRITICAL_SECTION lock;
+};
+
+void qemu_rec_mutex_destroy(QemuRecMutex *mutex);
+void qemu_rec_mutex_lock(QemuRecMutex *mutex);
+int qemu_rec_mutex_trylock(QemuRecMutex *mutex);
+void qemu_rec_mutex_unlock(QemuRecMutex *mutex);
+
 struct QemuCond {
     LONG waiters, target;
     HANDLE sema;

include/qemu/thread.h

@@ -25,6 +25,9 @@ void qemu_mutex_lock(QemuMutex *mutex);
 int qemu_mutex_trylock(QemuMutex *mutex);
 void qemu_mutex_unlock(QemuMutex *mutex);
 
+/* Prototypes for other functions are in thread-posix.h/thread-win32.h.  */
+void qemu_rec_mutex_init(QemuRecMutex *mutex);
+
 void qemu_cond_init(QemuCond *cond);
 void qemu_cond_destroy(QemuCond *cond);
 

util/qemu-thread-posix.c

@@ -80,6 +80,20 @@ void qemu_mutex_unlock(QemuMutex *mutex)
         error_exit(err, __func__);
 }
 
+void qemu_rec_mutex_init(QemuRecMutex *mutex)
+{
+    int err;
+    pthread_mutexattr_t attr;
+
+    pthread_mutexattr_init(&attr);
+    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+    err = pthread_mutex_init(&mutex->lock, &attr);
+    pthread_mutexattr_destroy(&attr);
+    if (err) {
+        error_exit(err, __func__);
+    }
+}
+
 void qemu_cond_init(QemuCond *cond)
 {
     int err;

util/qemu-thread-win32.c

@@ -79,6 +79,31 @@ void qemu_mutex_unlock(QemuMutex *mutex)
     LeaveCriticalSection(&mutex->lock);
 }
 
+void qemu_rec_mutex_init(QemuRecMutex *mutex)
+{
+    InitializeCriticalSection(&mutex->lock);
+}
+
+void qemu_rec_mutex_destroy(QemuRecMutex *mutex)
+{
+    DeleteCriticalSection(&mutex->lock);
+}
+
+void qemu_rec_mutex_lock(QemuRecMutex *mutex)
+{
+    EnterCriticalSection(&mutex->lock);
+}
+
+int qemu_rec_mutex_trylock(QemuRecMutex *mutex)
+{
+    return !TryEnterCriticalSection(&mutex->lock);
+}
+
+void qemu_rec_mutex_unlock(QemuRecMutex *mutex)
+{
+    LeaveCriticalSection(&mutex->lock);
+}
+
 void qemu_cond_init(QemuCond *cond)
 {
     memset(cond, 0, sizeof(*cond));