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

/* SPDX-License-Identifier: GPL-2.0
 *
 * 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 */
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0
	2	*
	3	* wrapper/kref.h
	4	*
	5	* wrapper around linux/kref.h.
	6	*
	7	* Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*
	9	* This wrapper code is derived from Linux 3.19.2 include/linux/list.h
	10	* and include/linux/rculist.h, hence the GPLv2 license applied to this
	11	* file.
	12	*/
	13
	14	#ifndef _LTTNG_WRAPPER_KREF_H
	15	#define _LTTNG_WRAPPER_KREF_H
	16
	17	#include <linux/kref.h>
	18	#include <linux/rculist.h>
	19	#include <linux/version.h>
	20
	21	/*
	22	* lttng_kref_get: get reference count, checking for overflow.
	23	*
	24	* Return 1 if reference is taken, 0 otherwise (overflow).
	25	*/
	26	#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0))
	27	static inline int lttng_kref_get(struct kref *kref)
	28	{
	29	kref_get(kref);
	30	return 1;
	31	}
	32	#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
	33	static inline int lttng_kref_get(struct kref *kref)
	34	{
	35	return atomic_add_unless(&kref->refcount, 1, INT_MAX);
	36	}
	37	#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
	38
	39	#endif /* _LTTNG_WRAPPER_KREF_H */