dynamic_debug: add wildcard support to filter files/functions/modules

Add wildcard '*'(matches zero or more characters) and '?' (matches one
character) support when qurying debug flags.

Now we can open debug messages using keywords. eg:
1. open debug logs in all usb drivers
    echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
2.  open debug logs for usb xhci code
    echo "file *xhci* +p" > <debugfs>/dynamic_debug/control

Signed-off-by: Du, Changbin <changbin.du@gmail.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/dynamic_debug.c

@@ -8,6 +8,7 @@
  * By Greg Banks <gnb@melbourne.sgi.com>
  * Copyright (c) 2008 Silicon Graphics Inc.  All Rights Reserved.
  * Copyright (C) 2011 Bart Van Assche.  All Rights Reserved.
+ * Copyright (C) 2013 Du, Changbin <changbin.du@gmail.com>
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
@@ -24,6 +25,7 @@
 #include <linux/sysctl.h>
 #include <linux/ctype.h>
 #include <linux/string.h>
+#include <linux/parser.h>
 #include <linux/string_helpers.h>
 #include <linux/uaccess.h>
 #include <linux/dynamic_debug.h>
@@ -147,7 +149,8 @@ static int ddebug_change(const struct ddebug_query *query,
 	list_for_each_entry(dt, &ddebug_tables, link) {
 
 		/* match against the module name */
-		if (query->module && strcmp(query->module, dt->mod_name))
+		if (query->module &&
+		    !match_wildcard(query->module, dt->mod_name))
 			continue;
 
 		for (i = 0; i < dt->num_ddebugs; i++) {
@@ -155,14 +158,16 @@ static int ddebug_change(const struct ddebug_query *query,
 
 			/* match against the source filename */
 			if (query->filename &&
-			    strcmp(query->filename, dp->filename) &&
-			    strcmp(query->filename, kbasename(dp->filename)) &&
-			    strcmp(query->filename, trim_prefix(dp->filename)))
+			    !match_wildcard(query->filename, dp->filename) &&
+			    !match_wildcard(query->filename,
+					   kbasename(dp->filename)) &&
+			    !match_wildcard(query->filename,
+					   trim_prefix(dp->filename)))
 				continue;
 
 			/* match against the function */
 			if (query->function &&
-			    strcmp(query->function, dp->function))
+			    !match_wildcard(query->function, dp->function))
 				continue;
 
 			/* match against the format */