[PATCH 3/3] dyndbg: add source filename to prefix

[Thomas Weißschuh]

Printing the line number without the file is of limited usefulness.

Knowing the filename also makes it also easier to relate the logged
information to the controlfile.

Example:

    # modprobe test_dynamic_debug
    # echo 'file test_dynamic_debug.c =pfsl' > /proc/dynamic_debug/control
    # echo 1 > /sys/module/test_dynamic_debug/parameters/do_prints
    # dmesg | tail -2
    [   71.802212] do_cats:lib/test_dynamic_debug.c:103: test_dd: doing categories
    [   71.802227] do_levels:lib/test_dynamic_debug.c:123: test_dd: doing levels

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
 Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++--
 include/linux/dynamic_debug.h                     | 4 +++-
 lib/dynamic_debug.c                               | 4 ++++
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index faa22f77847a..f9fa8163fba6 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -216,13 +216,14 @@ The flags are::
   t    Include thread ID, or <intr>
   m    Include module name
   f    Include the function name
+  s    Include the source file name
   l    Include line number
 
 For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only
 the ``p`` flag has meaning, other flags are ignored.
 
-Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification.
-To clear all flags at once, use ``=_`` or ``-flmpt``.
+Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
+To clear all flags at once, use ``=_`` or ``-fslmpt``.
 
 
 Debug messages during Boot Process
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 41682278d2e8..0c77105d583c 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -37,10 +37,12 @@ struct _ddebug {
 #define _DPRINTK_FLAGS_INCL_FUNCNAME	(1<<2)
 #define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)
 #define _DPRINTK_FLAGS_INCL_TID		(1<<4)
+#define _DPRINTK_FLAGS_INCL_SOURCENAME	(1<<5)
 
 #define _DPRINTK_FLAGS_INCL_ANY		\
 	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
-	 _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID)
+	 _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID |\
+	 _DPRINTK_FLAGS_INCL_SOURCENAME)
 
 #if defined DEBUG
 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index e96ea427d8af..fa7418e35197 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -92,6 +92,7 @@ static const struct { unsigned flag:8; char opt_char; } opt_array[] = {
 	{ _DPRINTK_FLAGS_PRINT, 'p' },
 	{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
 	{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
+	{ _DPRINTK_FLAGS_INCL_SOURCENAME, 's' },
 	{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
 	{ _DPRINTK_FLAGS_INCL_TID, 't' },
 	{ _DPRINTK_FLAGS_NONE, '_' },
@@ -836,6 +837,9 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
 	if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
 		pos += snprintf(buf + pos, remaining(pos), "%s:",
 				desc->function);
+	if (desc->flags & _DPRINTK_FLAGS_INCL_SOURCENAME)
+		pos += snprintf(buf + pos, remaining(pos), "%s:",
+				trim_prefix(desc->filename));
 	if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
 		pos += snprintf(buf + pos, remaining(pos), "%d:",
 				desc->lineno);

-- 
2.39.1