[PATCH v2 15/59] dyndbg: hoist classmap-filter-by-modname up to ddebug_add_module

[Jim Cromie]

The body of ddebug_attach_module_classes() is dominated by a
code-block that finds the contiguous subrange of classmaps matching on
modname, and saves it into the ddebug_table's info record.

Implement this block in a macro to accommodate different component
vectors in the "box" (as named in the for_subvec macro).

And hoist its invocation out of ddebug_attach_module_classes() up into
ddebug_add_module().  This moves the filtering step up closer to
dynamic_debug_init(), which effectively does the same for builtin
pr_debug descriptors; segmenting them into subranges by modname.

Signed-off-by: Jim Cromie <jim.cromie at gmail.com>
---
 lib/dynamic_debug.c | 57 ++++++++++++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 22 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index f7ec2365ab40..192783ff7b98 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1242,30 +1242,34 @@ static const struct proc_ops proc_fops = {
 
 static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di)
 {
-	struct ddebug_class_map *cm;
-	int i, nc = 0;
-
-	/*
-	 * Find this module's classmaps in a subrange/wholerange of
-	 * the builtin/modular classmap vector/section.  Save the start
-	 * and length of the subrange at its edges.
-	 */
-	for_subvec(i, cm, di, maps) {
-		if (!strcmp(cm->mod_name, dt->mod_name)) {
-			if (!nc) {
-				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
-					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
-				dt->info.maps.start = cm;
-			}
-			nc++;
-		}
-	}
-	if (nc) {
-		dt->info.maps.len = nc;
-		vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
-	}
+	vpr_info("module:%s attached %d classes\n", dt->mod_name, dt->info.maps.len);
 }
 
+/*
+ * scan the named array: @_vec, ref'd from inside @_box, for the
+ * start,len of the sub-array of elements matching on ->mod_name;
+ * remember them in _dst.  Macro depends upon the fields being in both
+ * _box and _dst.
+ * @_i:   caller provided counter var, init'd by macro
+ * @_sp:  cursor into @_vec.
+ * @_box: ptr to a struct with @_vec, num__##@_vec, mod_name fields.
+ * @_vec: name of ref into array[T] of builtin/modular __section data.
+ * @_dst: ptr to struct with @_vec and num__##@_vec fields, both updated.
+ */
+#define dd_mark_vector_subrange(_i, _dst, _sp, _box, _vec) ({	\
+	int nc = 0;							\
+	for_subvec(_i, _sp, _box, _vec) {				\
+		if (!strcmp((_sp)->mod_name, (_dst)->mod_name)) {	\
+			if (!nc++)					\
+				(_dst)->info._vec.start = (_sp);	\
+		} else {						\
+			if (nc)						\
+				break; /* end of consecutive matches */ \
+		}							\
+	}								\
+	(_dst)->info._vec.len = nc;					\
+})
+
 /*
  * Allocate a new ddebug_table for the given module
  * and add it to the global list.
@@ -1273,6 +1277,8 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 {
 	struct ddebug_table *dt;
+	struct ddebug_class_map *cm;
+	int i;
 
 	if (!di->descs.len)
 		return 0;
@@ -1294,6 +1300,13 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 	dt->info = *di;
 
 	INIT_LIST_HEAD(&dt->link);
+	/*
+	 * for builtin modules, ddebug_init() insures that the di
+	 * cursor marks just the module's descriptors, but it doesn't
+	 * do so for the builtin class _maps & _users.  find the
+	 * start,len of the vectors by mod_name, save to dt.
+	 */
+	dd_mark_vector_subrange(i, dt, cm, di, maps);
 
 	if (di->maps.len)
 		ddebug_attach_module_classes(dt, di);
-- 
2.49.0