1 files changed, 20 insertions, 2 deletions

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 7e3c53a900d8..c18257b0fa72 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -17,8 +17,8 @@ struct _ddebug {
         const char *format;
         unsigned int lineno:18;
         /*
-         * The flags field controls the behaviour at the callsite.
-         * The bits here are changed dynamically when the user
+         * The flags field controls the behaviour at the callsite.
+         * The bits here are changed dynamically when the user
          * writes commands to <debugfs>/dynamic_debug/control
          */
 #define _DPRINTK_FLAGS_NONE     0
@@ -44,6 +44,9 @@ extern int ddebug_remove_module(const char *mod_name);
 extern __printf(2, 3)
 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 
+extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
+                                        const char *modname);
+
 struct device;
 
 extern __printf(3, 4)
@@ -94,11 +97,26 @@ do {								\
 
 #else
 
+#include <linux/string.h>
+#include <linux/errno.h>
+
 static inline int ddebug_remove_module(const char *mod)
 {
         return 0;
 }
 
+static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
+                                                const char *modname)
+{
+        if (strstr(param, "dyndbg")) {
+                /* avoid pr_warn(), which wants pr_fmt() fully defined */
+                printk(KERN_WARNING "dyndbg param is supported only in "
+                        "CONFIG_DYNAMIC_DEBUG builds\n");
+                return 0; /* allow and ignore */
+        }
+        return -EINVAL;
+}
+
 #define dynamic_pr_debug(fmt, ...)                                      \
         do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
 #define dynamic_dev_dbg(dev, fmt, ...)                                  \