[net-next,v2,07/11] 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>
---
 include/uapi/linux/devlink.h |  1 +
 net/core/devlink.c           | 51 ++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

Thu, Jan 17, 2019 at 10:59:16PM CET, eranbe@mellanox.com wrote:
>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>
>---
> include/uapi/linux/devlink.h |  1 +
> net/core/devlink.c           | 51 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 52 insertions(+)
>
>diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
>index 1c186fd77343..51b4d7612cf8 100644
>--- a/include/uapi/linux/devlink.h
>+++ b/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,
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index b224d0d31c0c..57252ca31e1e 100644
>--- a/net/core/devlink.c
>+++ b/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);

This is odd. You need to convert to number of "buffers" the magic value
the driver provided. And then couple lines below....


>+
>+	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);

....you call the driver with "buffers array", buffer size and number of
buffers. It should be just:

	struct devlink_msg_ctx msg_ctx;

	err = reporter->ops->diagnose(reporter, &msg_ctx);

and then;

	err = devlink_health_buffer_snd(info,
					devlink_cmd_health_reporter_diagnose,
					0, &msg_ctx);


>+	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 = {
>-- 
>2.17.1
>