dyndbg: fix problem parsing format="foo bar"

commit 14775b0496 ("dyndbg: accept query terms like file=bar and
module=foo") added the combined keyword=value parsing poorly; revert
most of it, keeping the keyword & arg change.

Instead, fix the tokenizer for the new input, by terminating the
keyword (an unquoted word) on '=' as well as space, thus letting the
tokenizer work on the quoted argument, like it would have previously.

Also add a few debug-prints to show more parsing context, into
tokenizer and parse-query, and use "keyword, value" in others.

Fixes: 14775b0496 ("dyndbg: accept query terms like file=bar and module=foo")
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200831182210.850852-4-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/dynamic_debug.c

@@ -237,6 +237,7 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 {
 	int nwords = 0;
 
+	vpr_info("entry, buf:'%s'\n", buf);
 	while (*buf) {
 		char *end;
 
@@ -247,6 +248,8 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 		if (*buf == '#')
 			break;	/* token starts comment, skip rest of line */
 
+		vpr_info("start-of-word:%d '%s'\n", nwords, buf);
+
 		/* find `end' of word, whitespace separated or quoted */
 		if (*buf == '"' || *buf == '\'') {
 			int quote = *buf++;
@@ -257,7 +260,9 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 				return -EINVAL;	/* unclosed quote */
 			}
 		} else {
-			for (end = buf; *end && !isspace(*end); end++)
+			for (end = buf;
+			     *end && *end != '=' && !isspace(*end);
+			     end++)
 				;
 			BUG_ON(end == buf);
 		}
@@ -373,30 +378,21 @@ static int ddebug_parse_query(char *words[], int nwords,
 	unsigned int i;
 	int rc = 0;
 	char *fline;
-	char *keyword, *arg;
 
-	if (modname)
+	if (nwords % 2 != 0) {
+		pr_err("expecting pairs of match-spec <value>\n");
+		return -EINVAL;
+	}
+	if (modname) {
 		/* support $modname.dyndbg=<multiple queries> */
+		vpr_info("module:%s queries:'%s'\n", modname);
 		query->module = modname;
+	}
+	for (i = 0; i < nwords; i += 2) {
+		char *keyword = words[i];
+		char *arg = words[i+1];
 
-	for (i = 0; i < nwords; i++) {
-		/* accept keyword=arg */
-		vpr_info("%d w:%s\n", i, words[i]);
-
-		keyword = words[i];
-		arg = strchr(keyword, '=');
-		if (arg) {
-			*arg++ = '\0';
-		} else {
-			i++; /* next word is arg */
-			if (!(i < nwords)) {
-				pr_err("missing arg to keyword: %s\n", keyword);
-				return -EINVAL;
-			}
-			arg = words[i];
-		}
-		vpr_info("%d key:%s arg:%s\n", i, keyword, arg);
-
+		vpr_info("keyword:'%s' value:'%s'\n", keyword, arg);
 		if (!strcmp(keyword, "func")) {
 			rc = check_set(&query->function, arg, "func");
 		} else if (!strcmp(keyword, "file")) {