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

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * wrapper/writeback.h
 *
 * wrapper around global_dirty_limit read. Using KALLSYMS with KALLSYMS_ALL
 * to get its address when available, else we need to have a kernel that
 * exports this variable to GPL modules.
 *
 * Copyright (C) 2013 Mentor Graphics Corp.
 */

#ifndef _LTTNG_WRAPPER_WRITEBACK_H
#define _LTTNG_WRAPPER_WRITEBACK_H

#include <lttng-kernel-version.h>

#ifdef CONFIG_KALLSYMS_ALL
#include <linux/kallsyms.h>
#include <wrapper/kallsyms.h>


#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,2,0)

static struct wb_domain *global_wb_domain_sym;

static inline
unsigned long wrapper_global_dirty_limit(void)
{
	if (!global_wb_domain_sym)
		global_wb_domain_sym =
			(void *) kallsyms_lookup_dataptr("global_wb_domain");
	if (global_wb_domain_sym) {
		return global_wb_domain_sym->dirty_limit;
	} else {
		printk_once(KERN_WARNING "LTTng: global_wb_domain symbol lookup failed.\n");
		return 0;
	}
}
#else

static unsigned long *global_dirty_limit_sym;

static inline
unsigned long wrapper_global_dirty_limit(void)
{
	if (!global_dirty_limit_sym)
		global_dirty_limit_sym =
			(void *) kallsyms_lookup_dataptr("global_dirty_limit");
	if (global_dirty_limit_sym) {
		return *global_dirty_limit_sym;
	} else {
		printk_once(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n");
		return 0;
	}
}
#endif

#else /* CONFIG_KALLSYMS_ALL */

#include <linux/writeback.h>

static inline
unsigned long wrapper_global_dirty_limit(void)
{
	return global_dirty_limit;
}

#endif

#endif /* _LTTNG_WRAPPER_WRITEBACK_H */
Commit	Line	Data
	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
	2	*
	3	* wrapper/writeback.h
	4	*
	5	* wrapper around global_dirty_limit read. Using KALLSYMS with KALLSYMS_ALL
	6	* to get its address when available, else we need to have a kernel that
	7	* exports this variable to GPL modules.
	8	*
	9	* Copyright (C) 2013 Mentor Graphics Corp.
	10	*/
	11
	12	#ifndef _LTTNG_WRAPPER_WRITEBACK_H
	13	#define _LTTNG_WRAPPER_WRITEBACK_H
	14
	15	#include <lttng-kernel-version.h>
	16
	17	#ifdef CONFIG_KALLSYMS_ALL
	18	#include <linux/kallsyms.h>
	19	#include <wrapper/kallsyms.h>
	20
	21
	22
	23	#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,2,0)
	24
	25	static struct wb_domain *global_wb_domain_sym;
	26
	27	static inline
	28	unsigned long wrapper_global_dirty_limit(void)
	29	{
	30	if (!global_wb_domain_sym)
	31	global_wb_domain_sym =
	32	(void *) kallsyms_lookup_dataptr("global_wb_domain");
	33	if (global_wb_domain_sym) {
	34	return global_wb_domain_sym->dirty_limit;
	35	} else {
	36	printk_once(KERN_WARNING "LTTng: global_wb_domain symbol lookup failed.\n");
	37	return 0;
	38	}
	39	}
	40	#else
	41
	42	static unsigned long *global_dirty_limit_sym;
	43
	44	static inline
	45	unsigned long wrapper_global_dirty_limit(void)
	46	{
	47	if (!global_dirty_limit_sym)
	48	global_dirty_limit_sym =
	49	(void *) kallsyms_lookup_dataptr("global_dirty_limit");
	50	if (global_dirty_limit_sym) {
	51	return *global_dirty_limit_sym;
	52	} else {
	53	printk_once(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n");
	54	return 0;
	55	}
	56	}
	57	#endif
	58
	59	#else /* CONFIG_KALLSYMS_ALL */
	60
	61	#include <linux/writeback.h>
	62
	63	static inline
	64	unsigned long wrapper_global_dirty_limit(void)
	65	{
	66	return global_dirty_limit;
	67	}
	68
	69	#endif
	70
	71	#endif /* _LTTNG_WRAPPER_WRITEBACK_H */