Treat comma as a token terminator, just like a space.  This allows a
user to avoid quoting hassles when spaces are otherwise needed:

 :#> modprobe drm dyndbg=class,DRM_UT_CORE,+p\;class,DRM_UT_KMS,+p

or as a boot arg:

 drm.dyndbg=class,DRM_UT_CORE,+p  # todo: support multi-query here

Given the many ways a boot-line +args can be assembled and then passed
in/down/around shell based tools, this may allow side-stepping all
sorts of quoting hassles thru those layers.

existing query format:

 modprobe test_dynamic_debug dyndbg="class D2_CORE +p"

new format:

 modprobe test_dynamic_debug dyndbg=class,D2_CORE,+p

ALSO

selftests-dyndbg: add comma_terminator_tests

New fn validates parsing and effect of queries using combinations of
commas and spaces to delimit the tokens.

It manipulates pr-debugs in builtin module/params, so might have deps
I havent foreseen on odd configurations.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Co-developed-by: Łukasz Bartosik <ukaszb@chromium.org>
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
---
- skip comma tests if no builtins
-v3 squash in tests and doc
---
 .../admin-guide/dynamic-debug-howto.rst       |  9 +++++---
 lib/dynamic_debug.c                           | 17 +++++++++++----
 .../dynamic_debug/dyndbg_selftest.sh          | 21 ++++++++++++++++++-
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 63a511f2337b..e2dbb5d9b314 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -78,11 +78,12 @@ Command Language Reference
 ==========================
 
 At the basic lexical level, a command is a sequence of words separated
-by spaces or tabs.  So these are all equivalent::
+by spaces, tabs, or commas.  So these are all equivalent::
 
   :#> ddcmd file svcsock.c line 1603 +p
   :#> ddcmd "file svcsock.c line 1603 +p"
   :#> ddcmd '  file   svcsock.c     line  1603 +p  '
+  :#> ddcmd file,svcsock.c,line,1603,+p
 
 Command submissions are bounded by a write() system call.
 Multiple commands can be written together, separated by ``;`` or ``\n``::
@@ -167,9 +168,11 @@ module
     The given string is compared against the module name
     of each callsite.  The module name is the string as
     seen in ``lsmod``, i.e. without the directory or the ``.ko``
-    suffix and with ``-`` changed to ``_``.  Examples::
+    suffix and with ``-`` changed to ``_``.
 
-	module sunrpc
+    Examples::
+
+	module,sunrpc	# with ',' as token separator
 	module nfsd
 	module drm*	# both drm, drm_kms_helper
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0d603caadef8..5737f1b4eba8 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -299,6 +299,14 @@ static int ddebug_change(const struct ddebug_query *query, struct flag_settings
 	return nfound;
 }
 
+static char *skip_spaces_and_commas(const char *str)
+{
+	str = skip_spaces(str);
+	while (*str == ',')
+		str = skip_spaces(++str);
+	return (char *)str;
+}
+
 /*
  * Split the buffer `buf' into space-separated words.
  * Handles simple " and ' quoting, i.e. without nested,
@@ -312,8 +320,8 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 	while (*buf) {
 		char *end;
 
-		/* Skip leading whitespace */
-		buf = skip_spaces(buf);
+		/* Skip leading whitespace and comma */
+		buf = skip_spaces_and_commas(buf);
 		if (!*buf)
 			break;	/* oh, it was trailing whitespace */
 		if (*buf == '#')
@@ -329,7 +337,7 @@ 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 && !isspace(*end) && *end != ','; end++)
 				;
 			if (end == buf) {
 				pr_err("parse err after word:%d=%s\n", nwords,
@@ -601,7 +609,8 @@ static int ddebug_exec_queries(char *query, const char *modname)
 		if (split)
 			*split++ = '\0';
 
-		query = skip_spaces(query);
+		query = skip_spaces_and_commas(query);
+
 		if (!query || !*query || *query == '#')
 			continue;
 
diff --git a/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh b/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh
index 465fad3f392c..c7bf521f36ee 100755
--- a/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh
+++ b/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh
@@ -216,7 +216,7 @@ function check_err_msg() {
 function basic_tests {
     echo -e "${GREEN}# BASIC_TESTS ${NC}"
     if [ $LACK_DD_BUILTIN -eq 1 ]; then
-	echo "SKIP"
+	echo "SKIP - test requires params, which is a builtin module"
 	return
     fi
     ddcmd =_ # zero everything
@@ -238,8 +238,27 @@ EOF
     ddcmd =_
 }
 
+function comma_terminator_tests {
+    echo -e "${GREEN}# COMMA_TERMINATOR_TESTS ${NC}"
+    if [ $LACK_DD_BUILTIN -eq 1 ]; then
+	echo "SKIP - test requires params, which is a builtin module"
+	return
+    fi
+    # try combos of spaces & commas
+    check_match_ct '\[params\]' 4 -r
+    ddcmd module,params,=_		# commas as spaces
+    ddcmd module,params,+mpf		# turn on module's pr-debugs
+    check_match_ct =pmf 4
+    ddcmd ,module ,, ,  params, -p
+    check_match_ct =mf 4
+    ddcmd " , module ,,, ,  params, -m"	#
+    check_match_ct =f 4
+    ddcmd =_
+}
+
 tests_list=(
     basic_tests
+    comma_terminator_tests
 )
 
 # Run tests
-- 
2.49.0