[PATCH v8 19/43] dyndbg: refactor param_set_dyndbg_classes and below

@@ -618,9 +618,10 @@ static int ddebug_exec_queries(char *query, const char *modname)
 	return nfound;
 }
 
-/* apply a new bitmap to the sys-knob's current bit-state */
+/* apply a new class-param setting */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     unsigned long *new_bits, unsigned long *old_bits)
+				     unsigned long *new_bits, unsigned long *old_bits,
+				     const char *query_modname)
 {
 #define QUERY_SIZE 128
 	char query[QUERY_SIZE];

@@ -628,7 +629,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	v2pr_info("apply: 0x%lx to: 0x%lx\n", *new_bits, *old_bits);
+	if (*new_bits != *old_bits)
+		v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+			  *old_bits, query_modname ?: "'*'");
 
 	for (bi = 0; bi < map->length; bi++) {
 		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))

@@ -637,12 +640,16 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
 			 test_bit(bi, new_bits) ? '+' : '-', dcp->flags);
 
-		ct = ddebug_exec_queries(query, NULL);
+		ct = ddebug_exec_queries(query, query_modname);
 		matches += ct;
 
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
+	if (*new_bits != *old_bits)
+		v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+			  *old_bits, query_modname ?: "'*'");
+
 	return matches;
 }
 

@@ -651,22 +658,17 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 
 #define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)
 
-/**
- * param_set_dyndbg_classes - class FOO >control
- * @instr: string echo>d to sysfs, input depends on map_type
- * @kp:    kp->arg has state: bits/lvl, map, map_type
- *
- * Enable/disable prdbgs by their class, as given in the arguments to
- * DECLARE_DYNDBG_CLASSMAP.  For LEVEL map-types, enforce relative
- * levels by bitpos.
- *
- * Returns: 0 or <0 if error.
+/*
+ * param-setter helper to validate numeric input, clamp its value by
+ * the classmap type and size, and apply the bits.
  */
-int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+static int param_set_dyndbg_module_classes(const char *instr,
+					   const struct kernel_param *kp,
+					   const char *mod_name)
 {
 	const struct ddebug_class_param *dcp = kp->arg;
 	const struct ddebug_class_map *map = dcp->map;
-	unsigned long inrep, new_bits, old_bits;
+	unsigned long inrep, new_bits, old_bits, old_val;
 	int rc, totct = 0;
 
 	rc = kstrtoul(instr, 0, &inrep);

@@ -686,9 +688,10 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
-		v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits);
-		*dcp->bits = inrep;
+		old_val = READ_ONCE(*dcp->bits);
+		v2pr_info("bits:0x%lx > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp));
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, &old_val, mod_name);
+		WRITE_ONCE(*dcp->bits, inrep);
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
 		/* input is bitpos, of highest verbosity to be enabled */

@@ -697,11 +700,12 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 				KP_NAME(kp), inrep, map->length);
 			inrep = map->length;
 		}
-		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
+		old_val = READ_ONCE(*dcp->lvl);
+		old_bits = CLASSMAP_BITMASK(old_val);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits);
-		*dcp->lvl = inrep;
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, mod_name);
+		WRITE_ONCE(*dcp->lvl, inrep);
 		break;
 	default:
 		pr_warn("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);

@@ -710,16 +714,33 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 	vpr_info("%s: total matches: %d\n", KP_NAME(kp), totct);
 	return 0;
 }
+
+/**
+ * param_set_dyndbg_classes - classmap-based kernel parameter setter
+ * @instr: string value to set (numeric bitmask or level)
+ * @kp:    kernel parameter info referencing classmap state
+ *
+ * Enable or disable all class'd pr_debug callsites in the classmap,
+ * independent of the module they're in.
+ *
+ * Returns: 0 on success, or a negative error code.
+ */
+int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+{
+	return param_set_dyndbg_module_classes(instr, kp, NULL);
+}
 EXPORT_SYMBOL(param_set_dyndbg_classes);
 
 /**
- * param_get_dyndbg_classes - classes reader
+ * param_get_dyndbg_classes - classmap kparam getter
  * @buffer: string description of controlled bits -> classes
  * @kp:     kp->arg has state: bits, map
  *
- * Reads last written state, underlying prdbg state may have been
- * altered by direct >control.  Displays 0x for DISJOINT, 0-N for
- * LEVEL Returns: #chars written or <0 on error
+ * Reads last written state, underlying pr_debug states may have been
+ * altered by direct >control.  Displays 0x for DISJOINT classmap
+ * types, 0-N for LEVEL types.
+ *
+ * Returns: ct of chars written or <0 on error
  */
 int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 {