wrapper/genhd.h

   1 #ifndef _LTTNG_WRAPPER_GENHD_H
   2 #define _LTTNG_WRAPPER_GENHD_H
   3
   4 /*
   5  * wrapper/genhd.h
   6  *
   7  * wrapper around block layer functions and data structures. Using
   8  * KALLSYMS to get its address when available, else we need to have a
   9  * kernel that exports this function to GPL modules.
  10  *
  11  * Copyright (C) 2011-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  12  *
  13  * This library is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU Lesser General Public
  15  * License as published by the Free Software Foundation; only
  16  * version 2.1 of the License.
  17  *
  18  * This library is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  21  * Lesser General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU Lesser General Public
  24  * License along with this library; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  26  */
  27
  28 #include <linux/genhd.h>
  29
  30 #ifdef CONFIG_KALLSYMS
  31
  32 #include <linux/kallsyms.h>
  33 #include <wrapper/kallsyms.h>
  34
  35 static inline
  36 char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
  37 {
  38         char *(*disk_name_sym)(struct gendisk *hd, int partno, char *buf);
  39
  40         disk_name_sym = (void *) kallsyms_lookup_funcptr("disk_name");
  41         if (disk_name_sym) {
  42                 return disk_name_sym(hd, partno, buf);
  43         } else {
  44                 printk_once(KERN_WARNING "LTTng: disk_name symbol lookup failed.\n");
  45                 return NULL;
  46         }
  47 }
  48
  49 #else
  50
  51 static inline
  52 char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
  53 {
  54         return disk_name(hd, partno, buf);
  55 }
  56
  57 #endif
  58
  59 #ifdef CONFIG_KALLSYMS_ALL
  60
  61 static inline
  62 struct class *wrapper_get_block_class(void)
  63 {
  64         struct class *ptr_block_class;
  65
  66         ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class");
  67         if (!ptr_block_class) {
  68                 printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
  69                 return NULL;
  70         }
  71         return ptr_block_class;
  72 }
  73
  74 static inline
  75 struct device_type *wrapper_get_disk_type(void)
  76 {
  77         struct device_type *ptr_disk_type;
  78
  79         ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type");
  80         if (!ptr_disk_type) {
  81                 printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
  82                 return NULL;
  83         }
  84         return ptr_disk_type;
  85 }
  86
  87 #else
  88
  89 static inline
  90 struct class *wrapper_get_block_class(void)
  91 {
  92         /*
  93          * Symbol block_class is not exported.
  94          * TODO: return &block_class;
  95          */
  96         /* Feature currently unavailable without KALLSYMS_ALL */
  97         return NULL;
  98 }
  99
 100 static inline
 101 struct device_type *wrapper_get_disk_type(void)
 102 {
 103         /*
 104          * Symbol disk_type is not exported.
 105          * TODO: return &disk_type;
 106          */
 107         /* Feature currently unavailable without KALLSYMS_ALL */
 108         return NULL;
 109 }
 110
 111 #endif
 112
 113 #endif /* _LTTNG_WRAPPER_GENHD_H */