[Qemu-devel] [PATCH 1/2] Introduce QemuRWLock

[Harsh Prateek Bora <harsh@linux.vnet.ibm.com>]

SynthFS introduced in
http://lists.gnu.org/archive/html/qemu-devel/2011-09/msg01206.html
uses pthread_rwlock_* APIs for rwlocks, which raise the need of a generic
Qemu specific, os independent rwlock APIs. This patch introduces the same.
Another patch to switch pthread_rwlock_* into qemu_rwlock_* follows.

Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
---
 qemu-thread-posix.c |   26 ++++++++++++++++++++++++++
 qemu-thread-posix.h |    4 ++++
 qemu-thread.h       |    6 ++++++
 3 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/qemu-thread-posix.c b/qemu-thread-posix.c
index ac3c0c9..9ae7f44 100644
--- a/qemu-thread-posix.c
+++ b/qemu-thread-posix.c
@@ -147,3 +147,29 @@ void qemu_thread_exit(void *retval)
 {
     pthread_exit(retval);
 }
+
+int qemu_rwlock_wrlock(QemuRWLock *rwlock)
+{
+    return pthread_rwlock_wrlock(&rwlock->rwl);
+}
+
+int qemu_rwlock_unlock(QemuRWLock *rwlock)
+{
+    return pthread_rwlock_unlock(&rwlock->rwl);
+}
+
+int qemu_rwlock_rdlock(QemuRWLock *rwlock)
+{
+    return pthread_rwlock_rdlock(&rwlock->rwl);
+}
+
+void qemu_rwlock_init(QemuRWLock *rwlock)
+{
+    int err;
+    pthread_rwlockattr_t rwlockattr;
+
+    pthread_rwlockattr_init(&rwlockattr);
+    err = pthread_rwlock_init(&rwlock->rwl, &rwlockattr);
+    if (err)
+        error_exit(err, __func__);
+}
diff --git a/qemu-thread-posix.h b/qemu-thread-posix.h
index ee4618e..8c1e4f6 100644
--- a/qemu-thread-posix.h
+++ b/qemu-thread-posix.h
@@ -14,4 +14,8 @@ struct QemuThread {
     pthread_t thread;
 };
 
+struct QemuRWLock {
+    pthread_rwlock_t rwl;
+};
+
 #endif
diff --git a/qemu-thread.h b/qemu-thread.h
index 0a73d50..44321fb 100644
--- a/qemu-thread.h
+++ b/qemu-thread.h
@@ -6,6 +6,7 @@
 typedef struct QemuMutex QemuMutex;
 typedef struct QemuCond QemuCond;
 typedef struct QemuThread QemuThread;
+typedef struct QemuRWLock QemuRWLock;
 
 #ifdef _WIN32
 #include "qemu-thread-win32.h"
@@ -31,6 +32,11 @@ void qemu_cond_signal(QemuCond *cond);
 void qemu_cond_broadcast(QemuCond *cond);
 void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex);
 
+void qemu_rwlock_init(QemuRWLock *rwlock);
+int qemu_rwlock_rdlock(QemuRWLock *rwlock);
+int qemu_rwlock_wrlock(QemuRWLock *rwlock);
+int qemu_rwlock_unlock(QemuRWLock *rwlock);
+
 void qemu_thread_create(QemuThread *thread,
                        void *(*start_routine)(void*),
                        void *arg);
-- 
1.7.4.1