Add a read/write lock implementation

Add virRWLock backed up by a POSIX rwlock primitive

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index f890c6ecee9a9d022647500370581d7879b7e12e..94901c7ef02ef17808f79938aaf3fc24cdc6fc8c 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1818,6 +1818,11 @@ virMutexInitRecursive;
 virMutexLock;
 virMutexUnlock;
 virOnce;
+virRWLockDestroy;
+virRWLockInit;
+virRWLockRead;
+virRWLockUnlock;
+virRWLockWrite;
 virThreadCancel;
 virThreadCreate;
 virThreadID;

diff --git a/src/util/virthread.h b/src/util/virthread.h
index 84d3bdc8287b48f7b5587f3a5fc9860c3ac8e35f..7015d6008261ebfacf007bf11b0da79f265ee7d7 100644 (file)
--- a/src/util/virthread.h
+++ b/src/util/virthread.h
@@ -28,6 +28,9 @@
 typedef struct virMutex virMutex;
 typedef virMutex *virMutexPtr;
 
+typedef struct virRWLock virRWLock;
+typedef virRWLock *virRWLockPtr;
+
 typedef struct virCond virCond;
 typedef virCond *virCondPtr;
 
@@ -89,6 +92,13 @@ void virMutexLock(virMutexPtr m);
 void virMutexUnlock(virMutexPtr m);
 
 
+int virRWLockInit(virRWLockPtr m) ATTRIBUTE_RETURN_CHECK;
+void virRWLockDestroy(virRWLockPtr m);
+
+void virRWLockRead(virRWLockPtr m);
+void virRWLockWrite(virRWLockPtr m);
+void virRWLockUnlock(virRWLockPtr m);
+
 
 int virCondInit(virCondPtr c) ATTRIBUTE_RETURN_CHECK;
 int virCondDestroy(virCondPtr c);

diff --git a/src/util/virthreadpthread.c b/src/util/virthreadpthread.c
index ca841e49782591b577fc9c0146d56b6c1f745490..38b6454c27efadb0eee9403dd2e6fbfe6fb783ea 100644 (file)
--- a/src/util/virthreadpthread.c
+++ b/src/util/virthreadpthread.c
@@ -91,6 +91,39 @@ void virMutexUnlock(virMutexPtr m)
 }
 
 
+int virRWLockInit(virRWLockPtr m)
+{
+    int ret;
+    ret = pthread_rwlock_init(&m->lock, NULL);
+    if (ret != 0) {
+        errno = ret;
+        return -1;
+    }
+    return 0;
+}
+
+void virRWLockDestroy(virRWLockPtr m)
+{
+    pthread_rwlock_destroy(&m->lock);
+}
+
+
+void virRWLockRead(virRWLockPtr m)
+{
+    pthread_rwlock_rdlock(&m->lock);
+}
+
+void virRWLockWrite(virRWLockPtr m)
+{
+    pthread_rwlock_wrlock(&m->lock);
+}
+
+
+void virRWLockUnlock(virRWLockPtr m)
+{
+    pthread_rwlock_unlock(&m->lock);
+}
+
 int virCondInit(virCondPtr c)
 {
     int ret;

diff --git a/src/util/virthreadpthread.h b/src/util/virthreadpthread.h
index b9f1319fc1098dec24ae2bf32a697f1f73f0e4f2..cb607d0d72a1c6b630498e46deb603f47167ef0d 100644 (file)
--- a/src/util/virthreadpthread.h
+++ b/src/util/virthreadpthread.h
@@ -27,6 +27,10 @@ struct virMutex {
     pthread_mutex_t lock;
 };
 
+struct virRWLock {
+    pthread_rwlock_t lock;
+};
+
 struct virCond {
     pthread_cond_t cond;
 };

diff --git a/src/util/virthreadwin32.c b/src/util/virthreadwin32.c
index 5d6277f246cd6465c7181733fc90f7f2b43b03f5..a9e235384e424948a601c51e078cf747bf6efc69 100644 (file)
--- a/src/util/virthreadwin32.c
+++ b/src/util/virthreadwin32.c
@@ -123,6 +123,25 @@ void virMutexUnlock(virMutexPtr m)
 }
 
 
+int virRWLockInit(virRWLockPtr m ATTRIBUTE_UNUSED)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
+void virRWLockDestroy(virRWLockPtr m ATTRIBUTE_UNUSED)
+{}
+
+
+void virRWLockRead(virRWLockPtr m ATTRIBUTE_UNUSED)
+{}
+
+void virRWLockWrite(virRWLockPtr m ATTRIBUTE_UNUSED)
+{}
+
+
+void virRWLockUnlock(virRWLockPtr m ATTRIBUTE_UNUSED)
+{}
 
 int virCondInit(virCondPtr c)
 {

diff --git a/src/util/virthreadwin32.h b/src/util/virthreadwin32.h
index 645031b696ada3d58e146d37d30fa0c084cae34c..31d9444cc1943f55f3ebf9ee1457d3bfcb86e971 100644 (file)
--- a/src/util/virthreadwin32.h
+++ b/src/util/virthreadwin32.h
@@ -30,6 +30,10 @@ struct virMutex {
     HANDLE lock;
 };
 
+struct virRWLock {
+    bool ignored;
+};
+
 struct virCond {
     virMutex lock;
     size_t nwaiters;