Cleanup: Move wrapper/ headers to include/wrapper/

[lttng-modules.git] / include / wrapper / kref.h

diff --git a/include/wrapper/kref.h b/include/wrapper/kref.h
new file mode 100644 (file)
index 0000000..f3b5053
--- /dev/null
+++ b/include/wrapper/kref.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * wrapper/kref.h
+ *
+ * wrapper around linux/kref.h.
+ *
+ * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This wrapper code is derived from Linux 3.19.2 include/linux/list.h
+ * and include/linux/rculist.h, hence the GPLv2 license applied to this
+ * file.
+ */
+
+#ifndef _LTTNG_WRAPPER_KREF_H
+#define _LTTNG_WRAPPER_KREF_H
+
+#include <linux/kref.h>
+#include <linux/rculist.h>
+#include <linux/version.h>
+
+/*
+ * lttng_kref_get: get reference count, checking for overflow.
+ *
+ * Return 1 if reference is taken, 0 otherwise (overflow).
+ */
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0))
+static inline int lttng_kref_get(struct kref *kref)
+{
+       kref_get(kref);
+       return 1;
+}
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
+static inline int lttng_kref_get(struct kref *kref)
+{
+       return atomic_add_unless(&kref->refcount, 1, INT_MAX);
+}
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
+
+#endif /* _LTTNG_WRAPPER_KREF_H */