[Qemu-devel] [PATCH 18/40] 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.

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    | 13 +++++++++++++
 util/qemu-thread-win32.c    | 25 +++++++++++++++++++++++++
 5 files changed, 57 insertions(+)

diff --git a/include/qemu/thread-posix.h b/include/qemu/thread-posix.h
index eb5c7a1..2fb6b90 100644
--- a/include/qemu/thread-posix.h
+++ b/include/qemu/thread-posix.h
@@ -3,6 +3,12 @@
 #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 385ff5f..50999c5 100644
--- a/include/qemu/thread-win32.h
+++ b/include/qemu/thread-win32.h
@@ -7,6 +7,16 @@ struct QemuMutex {
     LONG owner;
 };
 
+typedef struct QemuRecMutex QemuRecMutex;
+struct QemuRecMutex {
+    CRITICAL_SECTION lock;
+};
+
+void qemu_rec_mutex_destroy(QemuMutex *mutex);
+void qemu_rec_mutex_lock(QemuMutex *mutex);
+int qemu_rec_mutex_trylock(QemuMutex *mutex);
+void qemu_rec_mutex_unlock(QemuMutex *mutex);
+
 struct QemuCond {
     LONG waiters, target;
     HANDLE sema;
diff --git a/include/qemu/thread.h b/include/qemu/thread.h
index 5114ec8..981f3dc 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 dbd8094..4cc9f13 100644
--- a/util/qemu-thread-posix.c
+++ b/util/qemu-thread-posix.c
@@ -89,6 +89,19 @@ 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);
+    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 6cdd553..018b73e 100644
--- a/util/qemu-thread-win32.c
+++ b/util/qemu-thread-win32.c
@@ -80,6 +80,31 @@ 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));
-- 
1.8.3.1