Re: [PATCH] sysfs: add filter function to groups

Greg KH
2007-10-31T03:51:01Z

On Tue, Oct 30, 2007 at 01:25:43PM -0500, James Bottomley wrote:
> On Mon, 2007-10-29 at 18:58 +0100, Stefan Richter wrote:
> > James Bottomley wrote:
> > >> > struct attribute_group {
> > >> > const char *name;
> > >> > + int (*filter_show)(struct kobject *, int);
> >
> > > Actually, it returns a true/false value indicating whether the given
> > > attribute should be displayed.
> >
> > How about this:
> >
> > int (*is_visible)(...);
>
> OK, so is this latest revision acceptable to everyone?
>
> James
>
> Index: BUILD-2.6/fs/sysfs/group.c
> ===================================================================
> --- BUILD-2.6.orig/fs/sysfs/group.c 2007-10-28 17:27:04.000000000 -0500
> +++ BUILD-2.6/fs/sysfs/group.c 2007-10-30 12:35:47.000000000 -0500
> @@ -16,25 +16,31 @@
> #include "sysfs.h"
>
>
> -static void remove_files(struct sysfs_dirent *dir_sd,
> +static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
> const struct attribute_group *grp)
> {
> struct attribute *const* attr;
> + int i;
>
> - for (attr = grp->attrs; *attr; attr++)
> - sysfs_hash_and_remove(dir_sd, (*attr)->name);
> + for (i = 0, attr = grp->attrs; *attr; i++, attr++)
> + if (grp->is_visible &&
> + grp->is_visible(kobj, *attr, i))
> + sysfs_hash_and_remove(dir_sd, (*attr)->name);

Hm, doesn't this break for the zillions of attribute groups that do not
have the is_visible function set?

> -static int create_files(struct sysfs_dirent *dir_sd,
> +static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
> const struct attribute_group *grp)
> {
> struct attribute *const* attr;
> - int error = 0;
> + int error = 0, i;
>
> - for (attr = grp->attrs; *attr && !error; attr++)
> - error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
> + for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++)
> + if (grp->is_visible &&
> + grp->is_visible(kobj, *attr, i))
> + error |=
> + sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);

Same problem here, if grp->is_visible is not set, sysfs_add_file() would
never be called, right?

Other than the logic problem (I think), I have no issue with this idea
at all. Care to redo this so it works?

thanks,

greg k-h