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

From: Elliot Berman
Date: Thu Sep 29 2022 - 16:48:06 EST




On 9/29/2022 12:36 AM, Joe Perches wrote:
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;
}


Thanks! Applied for the next version.