Statedump event for block devices

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

diff --git a/wrapper/genhd.h b/wrapper/genhd.h
new file mode 100644 (file)
index 0000000..5bb390b
--- /dev/null
+++ b/wrapper/genhd.h
@@ -0,0 +1,113 @@
+#ifndef _LTTNG_WRAPPER_GENHD_H
+#define _LTTNG_WRAPPER_GENHD_H
+
+/*
+ * 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>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/genhd.h>
+
+#ifdef CONFIG_KALLSYMS
+
+#include <linux/kallsyms.h>
+#include "kallsyms.h"
+
+static inline
+char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
+{
+       char *(*disk_name_sym)(struct gendisk *hd, int partno, char *buf);
+
+       disk_name_sym = (void *) kallsyms_lookup_funcptr("disk_name");
+       if (disk_name_sym) {
+               return disk_name_sym(hd, partno, buf);
+       } else {
+               printk(KERN_WARNING "LTTng: disk_name symbol lookup failed.\n");
+               return NULL;
+       }
+}
+
+#else
+
+static inline
+char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
+{
+       return disk_name(hd, partno, buf);
+}
+
+#endif
+
+#ifdef CONFIG_KALLSYMS_ALL
+
+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(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
+               return NULL;
+       }
+       return ptr_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(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
+               return NULL;
+       }
+       return ptr_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 */