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
  18
  19 #include <linux/kallsyms.h>
  20 #include <wrapper/kallsyms.h>
  21
  22 static inline
  23 char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
  24 {
  25         char *(*disk_name_sym)(struct gendisk *hd, int partno, char *buf);
  26
  27         disk_name_sym = (void *) kallsyms_lookup_funcptr("disk_name");
  28         if (disk_name_sym) {
  29                 return disk_name_sym(hd, partno, buf);
  30         } else {
  31                 printk_once(KERN_WARNING "LTTng: disk_name symbol lookup failed.\n");
  32                 return NULL;
  33         }
  34 }
  35
  36 #else
  37
  38 static inline
  39 char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
  40 {
  41         return disk_name(hd, partno, buf);
  42 }
  43
  44 #endif
  45
  46 #ifdef CONFIG_KALLSYMS_ALL
  47
  48 static inline
  49 struct class *wrapper_get_block_class(void)
  50 {
  51         struct class *ptr_block_class;
  52
  53         ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class");
  54         if (!ptr_block_class) {
  55                 printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
  56                 return NULL;
  57         }
  58         return ptr_block_class;
  59 }
  60
  61 static inline
  62 struct device_type *wrapper_get_disk_type(void)
  63 {
  64         struct device_type *ptr_disk_type;
  65
  66         ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type");
  67         if (!ptr_disk_type) {
  68                 printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
  69                 return NULL;
  70         }
  71         return ptr_disk_type;
  72 }
  73
  74 #else
  75
  76 static inline
  77 struct class *wrapper_get_block_class(void)
  78 {
  79         /*
  80          * Symbol block_class is not exported.
  81          * TODO: return &block_class;
  82          */
  83         /* Feature currently unavailable without KALLSYMS_ALL */
  84         return NULL;
  85 }
  86
  87 static inline
  88 struct device_type *wrapper_get_disk_type(void)
  89 {
  90         /*
  91          * Symbol disk_type is not exported.
  92          * TODO: return &disk_type;
  93          */
  94         /* Feature currently unavailable without KALLSYMS_ALL */
  95         return NULL;
  96 }
  97
  98 #endif
  99
 100 #endif /* _LTTNG_WRAPPER_GENHD_H */