Re: [PATCH v5 3/4] of: overlay: add per overlay sysfs attributes

From: Greg Kroah-Hartman
Date: Sun Oct 04 2015 - 15:23:21 EST


On Wed, Sep 16, 2015 at 07:09:10PM +0300, Pantelis Antoniou wrote:
> The two default overlay attributes are:
>
> * A targets sysfs attribute listing the targets of the installed
> overlay. The targets list the path on the kernel's device tree
> where each overlay fragment is applied to
>
> * A per overlay can_remove sysfs attribute that reports whether
> the overlay can be removed or not due to another overlapping overlay.
>
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
> ---
> drivers/of/overlay.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> index 62cfb99..cff3c05 100644
> --- a/drivers/of/overlay.c
> +++ b/drivers/of/overlay.c
> @@ -373,8 +373,61 @@ static const struct attribute *overlay_global_attrs[] = {
> NULL
> };
>
> +static ssize_t can_remove_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + struct of_overlay *ov = kobj_to_overlay(kobj);
> +
> + return snprintf(buf, PAGE_SIZE, "%d\n", overlay_removal_is_ok(ov));
> +}
> +
> +static ssize_t targets_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + struct of_overlay *ov = kobj_to_overlay(kobj);
> + struct of_overlay_info *ovinfo;
> + char *s, *e;
> + ssize_t ret;
> + int i, len;
> +
> + s = buf;
> + e = buf + PAGE_SIZE;
> +
> + mutex_lock(&of_mutex);
> +
> + /* targets */
> + for (i = 0; i < ov->count; i++) {
> + ovinfo = &ov->ovinfo_tab[i];
> +
> + len = snprintf(s, e - s, "%s\n",
> + of_node_full_name(ovinfo->target));
> + if (len == 0) {
> + ret = -ENOSPC;
> + goto err;
> + }
> + s += len;
> + }

Multiple values per sysfs file? Not ok, this is not going to work,
sorry, please fix.

greg k-h
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