include/wrapper/genhd.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   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>
  10  */
  11
  12 #ifndef _LTTNG_WRAPPER_GENHD_H
  13 #define _LTTNG_WRAPPER_GENHD_H
  14
  15 #include <linux/genhd.h>
  16
  17 #ifdef CONFIG_KALLSYMS_ALL
  18
  19 #include <linux/kallsyms.h>
  20 #include <wrapper/kallsyms.h>
  21
  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) {
  29                 printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
  30                 return NULL;
  31         }
  32         return ptr_block_class;
  33 }
  34
  35 static inline
  36 struct device_type *wrapper_get_disk_type(void)
  37 {
  38         struct device_type *ptr_disk_type;
  39
  40         ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type");
  41         if (!ptr_disk_type) {
  42                 printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
  43                 return NULL;
  44         }
  45         return ptr_disk_type;
  46 }
  47
  48 #else
  49
  50 static inline
  51 struct class *wrapper_get_block_class(void)
  52 {
  53         /*
  54          * Symbol block_class is not exported.
  55          * TODO: return &block_class;
  56          */
  57         /* Feature currently unavailable without KALLSYMS_ALL */
  58         return NULL;
  59 }
  60
  61 static inline
  62 struct device_type *wrapper_get_disk_type(void)
  63 {
  64         /*
  65          * Symbol disk_type is not exported.
  66          * TODO: return &disk_type;
  67          */
  68         /* Feature currently unavailable without KALLSYMS_ALL */
  69         return NULL;
  70 }
  71
  72 #endif
  73
  74 #endif /* _LTTNG_WRAPPER_GENHD_H */