-#ifndef _LTTNG_WRAPPER_WRITEBACK_H
-#define _LTTNG_WRAPPER_WRITEBACK_H
-
-/*
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
* wrapper/writeback.h
*
* wrapper around global_dirty_limit read. Using KALLSYMS with KALLSYMS_ALL
* exports this variable to GPL modules.
*
* Copyright (C) 2013 Mentor Graphics Corp.
- *
- * 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
*/
-#ifdef CONFIG_KALLSYMS_ALL
+#ifndef _LTTNG_WRAPPER_WRITEBACK_H
+#define _LTTNG_WRAPPER_WRITEBACK_H
+
+#include <lttng-kernel-version.h>
+#ifdef CONFIG_KALLSYMS_ALL
#include <linux/kallsyms.h>
#include <wrapper/kallsyms.h>
+
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,2,0)
+
+static struct wb_domain *global_wb_domain_sym;
+
+static inline
+unsigned long wrapper_global_dirty_limit(void)
+{
+ if (!global_wb_domain_sym)
+ global_wb_domain_sym =
+ (void *) kallsyms_lookup_dataptr("global_wb_domain");
+ if (global_wb_domain_sym) {
+ return global_wb_domain_sym->dirty_limit;
+ } else {
+ printk_once(KERN_WARNING "LTTng: global_wb_domain symbol lookup failed.\n");
+ return 0;
+ }
+}
+
+/*
+ * Canary function to check for 'global_wb_domain' at compile time.
+ *
+ * From 'include/linux/writeback.h':
+ *
+ * extern struct wb_domain global_wb_domain;
+ */
+static inline
+unsigned long __canary__global_wb_domain(void)
+{
+ return global_wb_domain.dirty_limit;
+}
+
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3,1,0)
+
static unsigned long *global_dirty_limit_sym;
static inline
if (global_dirty_limit_sym) {
return *global_dirty_limit_sym;
} else {
- printk(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n");
+ printk_once(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n");
return 0;
}
}
-#else
+/*
+ * Canary function to check for 'global_dirty_limit' at compile time.
+ *
+ * From 'include/linux/writeback.h':
+ *
+ * extern unsigned long global_dirty_limit;
+ */
+static inline
+unsigned long __canary__global_dirty_limit(void)
+{
+ return global_dirty_limit;
+}
+
+#endif
+
+#else /* CONFIG_KALLSYMS_ALL */
#include <linux/writeback.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,1,0)
static inline
unsigned long wrapper_global_dirty_limit(void)
{
return global_dirty_limit;
}
+#endif
#endif