[PATCH v2 09/27] Doc/dyndbg: document new class class_name query support

[Jim Cromie]

The added paragraph is slightly process oriented, rather than in
language of guarantees; I thought the implications were clear enough.

It does perhaps undersell the selectivity gained with string
class_names; only drm/* would sanely register DRM_UT_CORE etc, so
doing multiple "module {drm*,amdgpu,i915}" queries is unnecessary.

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
 Documentation/admin-guide/dynamic-debug-howto.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index a89cfa083155..01ca6f635dcc 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -35,6 +35,7 @@ Dynamic debug has even more useful features:
    - line number (including ranges of line numbers)
    - module name
    - format string
+   - class string (as known by each module)
 
  * Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
    which can be read to display the complete list of known debug
@@ -142,6 +143,7 @@ against.  Possible keywords are:::
 		 'file' string |
 		 'module' string |
 		 'format' string |
+		 'class' string |
 		 'line' line-range
 
   line-range ::= lineno |
@@ -203,6 +205,15 @@ format
 	format "nfsd: SETATTR"  // a neater way to match a format with whitespace
 	format 'nfsd: SETATTR'  // yet another way to match a format with whitespace
 
+class
+    The given class_name is validated against each module, which may
+    have registered a list of known class_names.  If the class_name is
+    found for a module, callsite matching and adjustment proceeds.
+    Examples::
+
+	class DRM_UT_KMS	# unless DRM wants different
+	class JUNK		# silent non-match
+
 line
     The given line number or range of line numbers is compared
     against the line number of each ``pr_debug()`` callsite.  A single
-- 
2.35.3