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

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * wrapper/genhd.h
 *
 * wrapper around block layer functions and data structures. Using
 * KALLSYMS to get its address when available, else we need to have a
 * kernel that exports this function to GPL modules.
 *
 * Copyright (C) 2011-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#ifndef _LTTNG_WRAPPER_GENHD_H
#define _LTTNG_WRAPPER_GENHD_H

#include <linux/genhd.h>

#ifdef CONFIG_KALLSYMS_ALL

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

static inline
struct class *wrapper_get_block_class(void)
{
	struct class *ptr_block_class;

	ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class");
	if (!ptr_block_class) {
		printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
		return NULL;
	}
	return ptr_block_class;
}

/*
 * Canary function to check for 'block_class' at compile time.
 *
 * From 'include/linux/genhd.h':
 *
 *   extern struct class block_class;
 */
static inline
struct class *__canary__get_block_class(void)
{
	return &block_class;
}

static inline
struct device_type *wrapper_get_disk_type(void)
{
	struct device_type *ptr_disk_type;

	ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type");
	if (!ptr_disk_type) {
		printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
		return NULL;
	}
	return ptr_disk_type;
}

/*
 * No canary for 'disk_type', it's only defined in 'block/genhd.c'.
 *
 * static inline
 * struct device_type *__canary__get_disk_type(void)
 * {
 * 	return &disk_type;
 * }
 */

#else

static inline
struct class *wrapper_get_block_class(void)
{
	/*
	 * Symbol block_class is not exported.
	 * TODO: return &block_class;
	 */
	/* Feature currently unavailable without KALLSYMS_ALL */
	return NULL;
}

static inline
struct device_type *wrapper_get_disk_type(void)
{
	/*
	 * Symbol disk_type is not exported.
	 * TODO: return &disk_type;
	 */
	/* Feature currently unavailable without KALLSYMS_ALL */
	return NULL;
}

#endif

#endif /* _LTTNG_WRAPPER_GENHD_H */
Commit	Line	Data
9f36eaed MJ	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
9f36eaed MJ	2	*
f0dbdefb HD	3	* wrapper/genhd.h
	4	*
	5	* wrapper around block layer functions and data structures. Using
	6	* KALLSYMS to get its address when available, else we need to have a
	7	* kernel that exports this function to GPL modules.
	8	*
	9	* Copyright (C) 2011-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
f0dbdefb HD	10	*/
f0dbdefb HD	11
9f36eaed MJ	12	#ifndef _LTTNG_WRAPPER_GENHD_H
	13	#define _LTTNG_WRAPPER_GENHD_H
	14
f0dbdefb HD	15	#include <linux/genhd.h>
f0dbdefb HD	16
bf5a011d	17	#ifdef CONFIG_KALLSYMS_ALL
f0dbdefb HD	18
f0dbdefb HD	19	#include <linux/kallsyms.h>
5a2f5e92	20	#include <wrapper/kallsyms.h>
f0dbdefb	21
f0dbdefb HD	22	static inline
	23	struct class *wrapper_get_block_class(void)
	24	{
	25	struct class *ptr_block_class;
	26
	27	ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class");
	28	if (!ptr_block_class) {
e36de50d	29	printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
f0dbdefb HD	30	return NULL;
	31	}
	32	return ptr_block_class;
	33	}
	34
9e52289b MJ	35	/*
	36	* Canary function to check for 'block_class' at compile time.
	37	*
	38	* From 'include/linux/genhd.h':
	39	*
	40	* extern struct class block_class;
	41	*/
	42	static inline
	43	struct class *__canary__get_block_class(void)
	44	{
	45	return &block_class;
	46	}
	47
f0dbdefb HD	48	static inline
	49	struct device_type *wrapper_get_disk_type(void)
	50	{
	51	struct device_type *ptr_disk_type;
	52
	53	ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type");
	54	if (!ptr_disk_type) {
e36de50d	55	printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
f0dbdefb HD	56	return NULL;
	57	}
	58	return ptr_disk_type;
	59	}
	60
9e52289b MJ	61	/*
	62	* No canary for 'disk_type', it's only defined in 'block/genhd.c'.
	63	*
	64	* static inline
	65	* struct device_type *__canary__get_disk_type(void)
	66	* {
	67	* return &disk_type;
	68	* }
	69	*/
	70
f0dbdefb HD	71	#else
	72
	73	static inline
	74	struct class *wrapper_get_block_class(void)
	75	{
	76	/*
	77	* Symbol block_class is not exported.
	78	* TODO: return &block_class;
	79	*/
	80	/* Feature currently unavailable without KALLSYMS_ALL */
	81	return NULL;
	82	}
	83
	84	static inline
	85	struct device_type *wrapper_get_disk_type(void)
	86	{
	87	/*
	88	* Symbol disk_type is not exported.
	89	* TODO: return &disk_type;
	90	*/
	91	/* Feature currently unavailable without KALLSYMS_ALL */
	92	return NULL;
	93	}
	94
	95	#endif
	96
	97	#endif /* _LTTNG_WRAPPER_GENHD_H */