X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=include%2Fwrapper%2Fwriteback.h;h=71369ab260d2c655e213c8f8b799f3f4e32cdb93;hb=9f2d2694cf0655682a1f0c29a7f3b868680524a5;hp=e5f36c258534a211ba76d8b3a316c2dc4bdb3ce1;hpb=117ab60f69a98dcbc365de8008ab93e6699d153a;p=lttng-modules.git

diff --git a/include/wrapper/writeback.h b/include/wrapper/writeback.h
index e5f36c25..71369ab2 100644
--- a/include/wrapper/writeback.h
+++ b/include/wrapper/writeback.h
@@ -12,16 +12,11 @@
 #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
@@ -37,24 +32,19 @@ unsigned long wrapper_global_dirty_limit(void)
 		return 0;
 	}
 }
-#else
-
-static unsigned long *global_dirty_limit_sym;
 
+/*
+ * 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 wrapper_global_dirty_limit(void)
+unsigned long __canary__global_wb_domain(void)
 {
-	if (!global_dirty_limit_sym)
-		global_dirty_limit_sym =
-			(void *) kallsyms_lookup_dataptr("global_dirty_limit");
-	if (global_dirty_limit_sym) {
-		return *global_dirty_limit_sym;
-	} else {
-		printk_once(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n");
-		return 0;
-	}
+	return global_wb_domain.dirty_limit;
 }
-#endif
 
 #else /* CONFIG_KALLSYMS_ALL */
 
@@ -66,6 +56,6 @@ unsigned long wrapper_global_dirty_limit(void)
 	return global_dirty_limit;
 }
 
-#endif
+#endif /* CONFIG_KALLSYMS_ALL */
 
 #endif /* _LTTNG_WRAPPER_WRITEBACK_H */