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Date:   Thu, 21 Jul 2022 14:56:57 +0200
From:   Jiri Pirko <jiri@nvidia.com>
To:     Vikas Gupta <vikas.gupta@broadcom.com>
Cc:     kuba@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, davem@davemloft.net,
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        leon@kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net,
        michael.chan@broadcom.com, andrew.gospodarek@broadcom.com
Subject: Re: [PATCH net-next v4 1/3] devlink: introduce framework for
 selftests
Message-ID: <YtlNGWp0D7M3PXvJ@nanopsycho>
References: <20220718062032.22426-1-vikas.gupta@broadcom.com>
 <20220721072121.43648-1-vikas.gupta@broadcom.com>
 <20220721072121.43648-2-vikas.gupta@broadcom.com>
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Thu, Jul 21, 2022 at 09:21:19AM CEST, vikas.gupta@broadcom.com wrote:
>Add a framework for running selftests.
>Framework exposes devlink commands and test suite(s) to the user
>to execute and query the supported tests by the driver.
>
>Below are new entries in devlink_nl_ops
>devlink_nl_cmd_selftests_list_doit/dumpit: To query the supported
>selftests by the drivers.
>devlink_nl_cmd_selftests_run: To execute selftests. Users can
>provide a test mask for executing group tests or standalone tests.
>
>Documentation/networking/devlink/ path is already part of MAINTAINERS &
>the new files come under this path. Hence no update needed to the
>MAINTAINERS
>
>Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
>Reviewed-by: Michael Chan <michael.chan@broadcom.com>
>Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
>---
> .../networking/devlink/devlink-selftests.rst  |  38 +++
> include/net/devlink.h                         |  20 ++
> include/uapi/linux/devlink.h                  |  29 +++
> net/core/devlink.c                            | 225 ++++++++++++++++++
> 4 files changed, 312 insertions(+)
> create mode 100644 Documentation/networking/devlink/devlink-selftests.rst
>
>diff --git a/Documentation/networking/devlink/devlink-selftests.rst b/Documentation/networking/devlink/devlink-selftests.rst
>new file mode 100644
>index 000000000000..0e9727895987
>--- /dev/null
>+++ b/Documentation/networking/devlink/devlink-selftests.rst
>@@ -0,0 +1,38 @@
>+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>+
>+=================
>+Devlink Selftests
>+=================
>+
>+The ``devlink-selftests`` API allows executing selftests on the device.
>+
>+Tests Mask
>+==========
>+The ``devlink-selftests`` command should be run with a mask indicating
>+the tests to be executed.
>+
>+Tests Description
>+=================
>+The following is a list of tests that drivers may execute.
>+
>+.. list-table:: List of tests
>+   :widths: 5 90
>+
>+   * - Name
>+     - Description
>+   * - ``DEVLINK_SELFTEST_FLASH``
>+     - Devices may have the firmware on non-volatile memory on the board, e.g.
>+       flash. This particular test helps to run a flash selftest on the device.
>+       Implementation of the test is left to the driver/firmware.
>+
>+example usage
>+-------------
>+
>+.. code:: shell
>+
>+    # Query selftests supported on the devlink device
>+    $ devlink dev selftests show DEV
>+    # Query selftests supported on all devlink devices
>+    $ devlink dev selftests show
>+    # Executes selftests on the device
>+    $ devlink dev selftests run DEV test flash

"test_id" to be consistend with the attr name and outputs. Please see
below. Devlink cmdline would accept "test" as well, so you can still use
this.


>diff --git a/include/net/devlink.h b/include/net/devlink.h
>index 88c701b375a2..085d761f1cd3 100644
>--- a/include/net/devlink.h
>+++ b/include/net/devlink.h
>@@ -1509,6 +1509,26 @@ struct devlink_ops {
> 				    struct devlink_rate *parent,
> 				    void *priv_child, void *priv_parent,
> 				    struct netlink_ext_ack *extack);
>+	/**
>+	 * selftests_check() - queries if selftest is supported
>+	 * @devlink: Devlink instance

Why capital "D"?


>+	 * @test_id: test index
>+	 * @extack: extack for reporting error messages
>+	 *
>+	 * Return: true if test is supported by the driver
>+	 */
>+	bool (*selftest_check)(struct devlink *devlink, int test_id,

Why this is an "int". I would be surprised to see a negative value here.
Have this unsigned please.


>+			       struct netlink_ext_ack *extack);
>+	/**
>+	 * selftest_run() - Runs a selftest
>+	 * @devlink: Devlink instance
>+	 * @test_id: test index
>+	 * @extack: extack for reporting error messages
>+	 *
>+	 * Return: Result of the test
>+	 */
>+	u8 (*selftest_run)(struct devlink *devlink, int test_id,

There too.


>+			   struct netlink_ext_ack *extack);
> };
> 
> void *devlink_priv(struct devlink *devlink);
>diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
>index b3d40a5d72ff..469846f40e6d 100644
>--- a/include/uapi/linux/devlink.h
>+++ b/include/uapi/linux/devlink.h
>@@ -136,6 +136,9 @@ enum devlink_command {
> 	DEVLINK_CMD_LINECARD_NEW,
> 	DEVLINK_CMD_LINECARD_DEL,
> 
>+	DEVLINK_CMD_SELFTESTS_LIST,	/* can dump */

The rest of the commands are named "_GET". Please be consistent with
them.


>+	DEVLINK_CMD_SELFTESTS_RUN,
>+
> 	/* add new commands above here */
> 	__DEVLINK_CMD_MAX,
> 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
>@@ -276,6 +279,31 @@ enum {
> #define DEVLINK_SUPPORTED_FLASH_OVERWRITE_SECTIONS \
> 	(_BITUL(__DEVLINK_FLASH_OVERWRITE_MAX_BIT) - 1)
> 
>+/* Commonly used test cases */

What do you mean by "commonly". Are there some others that are not
"common"? I don't follow.


>+enum devlink_selftest_attr {
>+	DEVLINK_SELFTEST_ATTR_UNSPEC,
>+	DEVLINK_SELFTEST_ATTR_FLASH,		/* flag */
>+
>+	__DEVLINK_SELFTEST_ATTR_MAX,
>+	DEVLINK_SELFTEST_ATTR_MAX = __DEVLINK_SELFTEST_ATTR_MAX - 1
>+};

To be consistent with the attr that caries this:

enum devlink_attr_selftest_test_id {
	DEVLINK_ATTR_SELFTEST_TEST_ID_UNSPEC,
	DEVLINK_ATTR_SELFTEST_TEST_ID_FLASH,		/* flag */

	__DEVLINK_ATTR_SELFTEST_TEST_ID_MAX,
	DEVLINK_ATTR_SELFTEST_TEST_ID_MAX = __DEVLINK_ATTR_SELFTEST_TEST_ID_MAX - 1

>+
>+enum devlink_selftest_result {
>+	DEVLINK_SELFTEST_SKIP,
>+	DEVLINK_SELFTEST_PASS,
>+	DEVLINK_SELFTEST_FAIL

It is common to have the enum name be root of names of the values.
Also, be consistent with the attr this value is carried over:

enum devlink_selftest_test_status {
	DEVLINK_SELFTEST_TEST_STATUS_SKIP,
	DEVLINK_SELFTEST_TEST_STATUS_PASS,
	DEVLINK_SELFTEST_TEST_STATUS_FAIL

That way, it is obvious to which enum the value belongs.


>+};
>+
>+enum devlink_selftest_result_attr {
>+	DEVLINK_SELFTEST_ATTR_RESULT_UNSPEC,
>+	DEVLINK_SELFTEST_ATTR_RESULT,		/* nested */
>+	DEVLINK_SELFTEST_ATTR_TEST_ID,		/* u32, devlink_selftest_attr */

add "enum" ?

>+	DEVLINK_SELFTEST_ATTR_TEST_STATUS,	/* u8, devlink_selftest_result */

add "enum" ?

The same note as above:
enum devlink_attr_selftest_result {
	DEVLINK_ATTR_SELFTEST_RESULT_UNSPEC,
	DEVLINK_ATTR_SELFTEST_RESULT,		  /* nested */
	DEVLINK_ATTR_SELFTEST_RESULT_TEST_ID,	  /* u32, enum devlink_selftest_attr */
	DEVLINK_ATTR_SELFTEST_RESULT_TEST_STATUS, /* u8, devlink_selftest_result */


>+
>+	__DEVLINK_SELFTEST_ATTR_RES_MAX,
>+	DEVLINK_SELFTEST_ATTR_RES_MAX = __DEVLINK_SELFTEST_ATTR_RES_MAX - 1
>+};
>+
> /**
>  * enum devlink_trap_action - Packet trap action.
>  * @DEVLINK_TRAP_ACTION_DROP: Packet is dropped by the device and a copy is not
>@@ -576,6 +604,7 @@ enum devlink_attr {
> 	DEVLINK_ATTR_LINECARD_TYPE,		/* string */
> 	DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES,	/* nested */
> 
>+	DEVLINK_ATTR_SELFTESTS_INFO,		/* nested */
> 	/* add new attributes above here, update the policy in devlink.c */
> 
> 	__DEVLINK_ATTR_MAX,
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index a9776ea923ae..ef9439f2502f 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -198,6 +198,10 @@ static const struct nla_policy devlink_function_nl_policy[DEVLINK_PORT_FUNCTION_
> 				 DEVLINK_PORT_FN_STATE_ACTIVE),
> };
> 
>+static const struct nla_policy devlink_selftest_nl_policy[DEVLINK_SELFTEST_ATTR_MAX + 1] = {
>+	[DEVLINK_SELFTEST_ATTR_FLASH] = { .type = NLA_FLAG },
>+};
>+
> static DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
> #define DEVLINK_REGISTERED XA_MARK_1
> 
>@@ -4791,6 +4795,215 @@ static int devlink_nl_cmd_flash_update(struct sk_buff *skb,
> 	return ret;
> }
> 
>+static int
>+devlink_nl_selftests_fill(struct sk_buff *msg, struct devlink *devlink,
>+			  u32 portid, u32 seq, int flags,
>+			  struct netlink_ext_ack *extack)
>+{
>+	struct nlattr *selftests_list;
>+	void *hdr;
>+	int err;
>+	int i;
>+
>+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags,
>+			  DEVLINK_CMD_SELFTESTS_LIST);
>+	if (!hdr)
>+		return -EMSGSIZE;
>+
>+	err = -EMSGSIZE;
>+	if (devlink_nl_put_handle(msg, devlink))
>+		goto err_cancel_msg;
>+
>+	selftests_list = nla_nest_start(msg, DEVLINK_ATTR_SELFTESTS_INFO);
>+	if (!selftests_list)
>+		goto err_cancel_msg;
>+
>+	for (i = 1; i < DEVLINK_SELFTEST_ATTR_MAX + 1; i++) {

**)
It is a bit odd to see "1" here. Maybe "DEVLINK_SELFTEST_ATTR_UNSPEC + 1"
would be more obvious for the reader.

also:
i < DEVLINK_SELFTEST_ATTR_MAX + 1
would be rather nicer to be:
i <= DEVLINK_SELFTEST_ATTR_MAX


>+		if (devlink->ops->selftest_check(devlink, i, extack)) {
>+			err = nla_put_flag(msg, i);
>+			if (err)
>+				goto err_cancel_msg;
>+		}
>+	}
>+
>+	nla_nest_end(msg, selftests_list);
>+

No need for this empty line.


>+	genlmsg_end(msg, hdr);
>+

No need for this empty line.


>+	return 0;
>+
>+err_cancel_msg:
>+	genlmsg_cancel(msg, hdr);
>+	return err;
>+}
>+
>+static int devlink_nl_cmd_selftests_list_doit(struct sk_buff *skb,
>+					      struct genl_info *info)
>+{
>+	struct devlink *devlink = info->user_ptr[0];
>+	struct sk_buff *msg;
>+	int err;
>+
>+	if (!devlink->ops->selftest_check)
>+		return -EOPNOTSUPP;
>+
>+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+	if (!msg)
>+		return -ENOMEM;
>+
>+	err = devlink_nl_selftests_fill(msg, devlink, info->snd_portid,
>+					info->snd_seq, 0, info->extack);
>+	if (err) {
>+		nlmsg_free(msg);
>+		return err;
>+	}
>+
>+	return genlmsg_reply(msg, info);
>+}
>+
>+static int devlink_nl_cmd_selftests_list_dumpit(struct sk_buff *msg,
>+						struct netlink_callback *cb)
>+{
>+	struct devlink *devlink;
>+	int start = cb->args[0];
>+	unsigned long index;
>+	int idx = 0;
>+	int err = 0;
>+
>+	mutex_lock(&devlink_mutex);
>+	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
>+		if (!devlink_try_get(devlink))
>+			continue;
>+
>+		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
>+			goto retry;
>+
>+		if (idx < start || !devlink->ops->selftest_check)
>+			goto inc;
>+
>+		mutex_lock(&devlink->lock);
>+		err = devlink_nl_selftests_fill(msg, devlink,
>+						NETLINK_CB(cb->skb).portid,
>+						cb->nlh->nlmsg_seq, NLM_F_MULTI,
>+						cb->extack);
>+		mutex_unlock(&devlink->lock);
>+		if (err) {
>+			devlink_put(devlink);
>+			break;
>+		}
>+inc:
>+		idx++;
>+retry:
>+		devlink_put(devlink);
>+	}
>+	mutex_unlock(&devlink_mutex);
>+
>+	if (err != -EMSGSIZE)
>+		return err;
>+
>+	cb->args[0] = idx;
>+	return msg->len;
>+}
>+
>+static int devlink_selftest_result_put(struct sk_buff *skb, int test_id,

unsigned.

>+				       u8 result)

Please be consistend and call this "test_status"


>+{
>+	struct nlattr *result_attr;
>+
>+	result_attr = nla_nest_start(skb, DEVLINK_SELFTEST_ATTR_RESULT);
>+	if (!result_attr)
>+		return -EMSGSIZE;
>+
>+	if (nla_put_u32(skb, DEVLINK_SELFTEST_ATTR_TEST_ID, test_id) ||
>+	    nla_put_u8(skb, DEVLINK_SELFTEST_ATTR_TEST_STATUS, result))
>+		goto nla_put_failure;
>+
>+	nla_nest_end(skb, result_attr);
>+

No need for this empty line.


>+	return 0;
>+
>+nla_put_failure:
>+	nla_nest_cancel(skb, result_attr);
>+	return -EMSGSIZE;
>+}
>+
>+static int devlink_nl_cmd_selftests_run(struct sk_buff *skb,
>+					struct genl_info *info)
>+{
>+	struct nlattr *tb[DEVLINK_SELFTEST_ATTR_MAX + 1];
>+	struct devlink *devlink = info->user_ptr[0];
>+	struct nlattr *attrs, *tests_info;
>+	struct sk_buff *msg;
>+	void *hdr;
>+	int err;
>+	int i;
>+
>+	if (!devlink->ops->selftest_run)
>+		return -EOPNOTSUPP;
>+
>+	if (!info->attrs[DEVLINK_ATTR_SELFTESTS_INFO])

Fill extack message here please.


>+		return -EINVAL;
>+
>+	attrs = info->attrs[DEVLINK_ATTR_SELFTESTS_INFO];
>+
>+	err = nla_parse_nested(tb, DEVLINK_SELFTEST_ATTR_MAX, attrs,
>+			       devlink_selftest_nl_policy, info->extack);
>+	if (err < 0)
>+		return err;
>+
>+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+	if (!msg)
>+		return -ENOMEM;
>+
>+	err = -EMSGSIZE;
>+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
>+			  &devlink_nl_family, 0, DEVLINK_CMD_SELFTESTS_RUN);
>+	if (!hdr)
>+		goto free_msg;
>+
>+	if (devlink_nl_put_handle(msg, devlink))
>+		goto genlmsg_cancel;
>+
>+	tests_info = nla_nest_start(msg, DEVLINK_ATTR_SELFTESTS_INFO);
>+	if (!tests_info)
>+		goto genlmsg_cancel;
>+
>+	for (i = 1; i < DEVLINK_SELFTEST_ATTR_MAX + 1; i++) {

Same notes to the iteration as above. **


>+		u8 res = DEVLINK_SELFTEST_SKIP;

u8 test_status;


>+
>+		if (nla_get_flag(tb[i])) {
>+			if (devlink->ops->selftest_check &&

No need to test in every iteration. I think it is safe to assume
that driver that does not fill selftest_check() does not support
selftests at all, so please move to the beginning of this function
alongside selftest_run() check:

	if (!devlink->ops->selftest_run || !devlink->ops->selftest_check)
		return -EOPNOTSUPP;

>+			    !devlink->ops->selftest_check(devlink, i,
>+							  info->extack)) {
>+				err = devlink_selftest_result_put(msg, i, res);

Just do devlink_selftest_result_put(msg, i, .._SKIP); here and avoid
initializing "res" at the beginning.


>+				if (err)
>+					goto selftests_list_nest_cancel;
>+				continue;
>+			}
>+
>+			res = devlink->ops->selftest_run(devlink, i,
>+							 info->extack);
>+			err = devlink_selftest_result_put(msg, i, res);
>+			if (err)
>+				goto selftests_list_nest_cancel;
>+		}
>+	}
>+
>+	nla_nest_end(msg, tests_info);
>+

No need for this empty line.


>+	genlmsg_end(msg, hdr);
>+

No need for this empty line.


>+	return genlmsg_reply(msg, info);
>+
>+selftests_list_nest_cancel:
>+	nla_nest_cancel(msg, tests_info);
>+genlmsg_cancel:
>+	genlmsg_cancel(msg, hdr);
>+free_msg:
>+	nlmsg_free(msg);
>+	return err;
>+}
>+
> static const struct devlink_param devlink_param_generic[] = {
> 	{
> 		.id = DEVLINK_PARAM_GENERIC_ID_INT_ERR_RESET,
>@@ -8997,6 +9210,7 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
> 	[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING },
> 	[DEVLINK_ATTR_LINECARD_INDEX] = { .type = NLA_U32 },
> 	[DEVLINK_ATTR_LINECARD_TYPE] = { .type = NLA_NUL_STRING },
>+	[DEVLINK_ATTR_SELFTESTS_INFO] = { .type = NLA_NESTED },
> };
> 
> static const struct genl_small_ops devlink_nl_ops[] = {
>@@ -9356,6 +9570,17 @@ static const struct genl_small_ops devlink_nl_ops[] = {
> 		.doit = devlink_nl_cmd_trap_policer_set_doit,
> 		.flags = GENL_ADMIN_PERM,
> 	},
>+	{
>+		.cmd = DEVLINK_CMD_SELFTESTS_LIST,
>+		.doit = devlink_nl_cmd_selftests_list_doit,
>+		.dumpit = devlink_nl_cmd_selftests_list_dumpit
>+		/* can be retrieved by unprivileged users */
>+	},
>+	{
>+		.cmd = DEVLINK_CMD_SELFTESTS_RUN,
>+		.doit = devlink_nl_cmd_selftests_run,
>+		.flags = GENL_ADMIN_PERM,
>+	},
> };
> 
> static struct genl_family devlink_nl_family __ro_after_init = {
>-- 
>2.31.1
>