[Qemu-devel] [PATCH 17/18] qemu-thread: introduce QemuRecMutex

[Paolo Bonzini <pbonzini@redhat.com>]

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>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/qemu/thread-posix.h |  6 ++++++
 include/qemu/thread-win32.h | 10 ++++++++++
 include/qemu/thread.h       |  3 +++
 util/qemu-thread-posix.c    | 14 ++++++++++++++
 util/qemu-thread-win32.c    | 25 +++++++++++++++++++++++++
 5 files changed, 58 insertions(+)

diff --git a/include/qemu/thread-posix.h b/include/qemu/thread-posix.h
index aa03567..09d1e15 100644
--- a/include/qemu/thread-posix.h
+++ b/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;
 };
diff --git a/include/qemu/thread-win32.h b/include/qemu/thread-win32.h
index c7ce8dc..5fb6541 100644
--- a/include/qemu/thread-win32.h
+++ b/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;
diff --git a/include/qemu/thread.h b/include/qemu/thread.h
index 31237e9..e8e665f 100644
--- a/include/qemu/thread.h
+++ b/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);
 
diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
index 74a3023..1bb00a8 100644
--- a/util/qemu-thread-posix.c
+++ b/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;
diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
index 98a5ddf..171d83c 100644
--- a/util/qemu-thread-win32.c
+++ b/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));
-- 
2.7.4