devlink: Add health diagnose command

Add devlink health diagnose command, in order to run a diagnose
operation over a specific reporter.

It is expected from driver's callback for diagnose command to fill it
via the buffer descriptors API. Devlink will parse it and convert it to
netlink nla API in order to pass it to the user.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/devlink.h

@@ -92,6 +92,7 @@ enum devlink_command {
 	DEVLINK_CMD_HEALTH_REPORTER_GET,
 	DEVLINK_CMD_HEALTH_REPORTER_SET,
 	DEVLINK_CMD_HEALTH_REPORTER_RECOVER,
+	DEVLINK_CMD_HEALTH_REPORTER_DIAGNOSE,
 
 	/* add new commands above here */
 	__DEVLINK_CMD_MAX,

net/core/devlink.c

@@ -4500,6 +4500,50 @@ static int devlink_nl_cmd_health_reporter_recover_doit(struct sk_buff *skb,
 	return devlink_health_reporter_recover(reporter, NULL);
 }
 
+static int devlink_nl_cmd_health_reporter_diagnose_doit(struct sk_buff *skb,
+							struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct devlink_health_reporter *reporter;
+	u64 num_of_buffers;
+	int err;
+
+	reporter = devlink_health_reporter_get_from_info(devlink, info);
+	if (!reporter)
+		return -EINVAL;
+
+	if (!reporter->ops->diagnose)
+		return -EOPNOTSUPP;
+
+	num_of_buffers =
+		DEVLINK_HEALTH_SIZE_TO_BUFFERS(reporter->ops->diagnose_size);
+
+	mutex_lock(&reporter->diagnose_lock);
+	devlink_health_buffers_reset(reporter->diagnose_buffers_array,
+				     num_of_buffers);
+
+	err = reporter->ops->diagnose(reporter,
+				      reporter->diagnose_buffers_array,
+				      DEVLINK_HEALTH_BUFFER_SIZE,
+				      num_of_buffers);
+	if (err)
+		goto out;
+
+	err = devlink_health_buffer_snd(info,
+					DEVLINK_CMD_HEALTH_REPORTER_DIAGNOSE,
+					0, reporter->diagnose_buffers_array,
+					num_of_buffers);
+	if (err)
+		goto out;
+
+	mutex_unlock(&reporter->diagnose_lock);
+	return 0;
+
+out:
+	mutex_unlock(&reporter->diagnose_lock);
+	return err;
+}
+
 static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
@@ -4770,6 +4814,13 @@ static const struct genl_ops devlink_nl_ops[] = {
 		.flags = GENL_ADMIN_PERM,
 		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
 	},
+	{
+		.cmd = DEVLINK_CMD_HEALTH_REPORTER_DIAGNOSE,
+		.doit = devlink_nl_cmd_health_reporter_diagnose_doit,
+		.policy = devlink_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
+	},
 };
 
 static struct genl_family devlink_nl_family __ro_after_init = {