Re: [PATCH v4 10/14] gunyah: sysfs: Add node to describe supported features

Joe Perches
2022-09-29T07:46:41Z

On Wed, 2022-09-28 at 12:56 -0700, Elliot Berman wrote:
> Add a sysfs node to list the features that the Gunyah hypervisor and
> Linux supports. For now, Linux support cspace (capability IDs) and
> message queues, so only report those..
[]
> diff --git a/drivers/virt/gunyah/sysfs.c b/drivers/virt/gunyah/sysfs.c
[]
> @@ -25,9 +25,24 @@ static ssize_t variant_show(struct kobject *kobj, struct kobj_attribute *attr, c
> }
> static struct kobj_attribute variant_attr = __ATTR_RO(variant);
>
> +static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr, char *buffer)
> +{
> + int len = 0;
> +
> + if (GH_IDENTIFY_PARTITION_CSPACE(gunyah_api.flags))
> + len += sysfs_emit_at(buffer, len, "cspace ");
> + if (GH_IDENTIFY_MSGQUEUE(gunyah_api.flags))
> + len += sysfs_emit_at(buffer, len, "message-queue ");
> +
> + len += sysfs_emit_at(buffer, len, "\n");
> + return len;
> +}

It's generally nicer to avoid unnecessary output spaces.

Perhaps:

{
int len = 0;

if (GH_IDENTIFY_PARTITION_CSPACE(gunyah_api.flags))
len += sysfs_emit_at(buffer, len, "cspace");
if (GH_IDENTIFY_MSGQUEUE(gunyah_api.flags)) {
if (len)
len += sysfs_emit_at(buffer, len, " ");
len += sysfs_emit_at(buffer, len, "message-queue");
}

len += sysfs_emit_at(buffer, len, "\n");

return len;
}