[PATCH v3 14/54] dyndbg: hoist classmap-filter-by-modname up to ddebug_add_module

[Louis Chauvet]

Le 02/04/2025 à 19:41, Jim Cromie a écrit :
> 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 | 56 ++++++++++++++++++++++++++-------------------
>   1 file changed, 32 insertions(+), 24 deletions(-)
> 
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index 104cf8abdf33..046c4ffb38f8 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -161,8 +161,8 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
>   }
>   
>   static struct _ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
> -							const char *class_string,
> -							int *class_id)
> +							 const char *class_string,
> +							 int *class_id)
>   {
>   	struct _ddebug_class_map *map;
>   	int i, idx;
> @@ -1224,30 +1224,34 @@ 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);
>   }
>   
> +/*
> + * Walk the @_box->@_vec member, over @_vec.start[0..len], and find
> + * the contiguous subrange of elements matching on ->mod_name.  Copy
> + * the subrange into @_dst.  This depends on vars defd by caller.
> + *
> + * @_i:   caller provided counter var, init'd by macro
> + * @_sp:  cursor into @_vec.
> + * @_box: contains member named @_vec
> + * @_vec: an array-ref, with: .start .len fields.
> + * @_dst: an array-ref: to remember the module's subrange

_dst must contains a member info which contains a member named @_vec. 
Can you specify this in the documentation?

Nitpick: Can you use the same order in documentation and macro definition?

> + */
> +#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.
> @@ -1255,6 +1259,8 @@ 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;
> @@ -1277,6 +1283,8 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
>   
>   	INIT_LIST_HEAD(&dt->link);
>   
> +	dd_mark_vector_subrange(i, dt, cm, di, maps);
> +
>   	if (di->maps.len)
>   		ddebug_attach_module_classes(dt, di);
>   

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com