[patch net-next 01/11] devlink: introduce nested devlink entity for line card

[Jiri Pirko <jiri@resnulli.us>]

From: Jiri Pirko <jiri@nvidia.com>

For the purpose of exposing device info and allow flash updated which is
going to be implemented in follow-up patches, introduce a possibility
for a line card to expose relation to nested devlink entity. The nested
devlink entity represents the line card.

Example:

$ devlink lc show pci/0000:01:00.0 lc 1
pci/0000:01:00.0:
  lc 1 state active type 16x100G nested_devlink auxiliary/mlxsw_core.lc.0
    supported_types:
       16x100G
$ devlink dev show auxiliary/mlxsw_core.lc.0
auxiliary/mlxsw_core.lc.0

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 include/net/devlink.h        |  2 ++
 include/uapi/linux/devlink.h |  2 ++
 net/core/devlink.c           | 42 ++++++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 2a2a2a0c93f7..83e62943e1d4 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1584,6 +1584,8 @@ void devlink_linecard_provision_clear(struct devlink_linecard *linecard);
 void devlink_linecard_provision_fail(struct devlink_linecard *linecard);
 void devlink_linecard_activate(struct devlink_linecard *linecard);
 void devlink_linecard_deactivate(struct devlink_linecard *linecard);
+void devlink_linecard_nested_dl_set(struct devlink_linecard *linecard,
+				    struct devlink *nested_devlink);
 int devlink_sb_register(struct devlink *devlink, unsigned int sb_index,
 			u32 size, u16 ingress_pools_count,
 			u16 egress_pools_count, u16 ingress_tc_count,
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index b3d40a5d72ff..541321695f52 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -576,6 +576,8 @@ enum devlink_attr {
 	DEVLINK_ATTR_LINECARD_TYPE,		/* string */
 	DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES,	/* nested */
 
+	DEVLINK_ATTR_NESTED_DEVLINK,		/* 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 db61f3a341cb..a5953cfe1baa 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -87,6 +87,7 @@ struct devlink_linecard {
 	const char *type;
 	struct devlink_linecard_type *types;
 	unsigned int types_count;
+	struct devlink *nested_devlink;
 };
 
 /**
@@ -796,6 +797,24 @@ static int devlink_nl_put_handle(struct sk_buff *msg, struct devlink *devlink)
 	return 0;
 }
 
+static int devlink_nl_put_nested_handle(struct sk_buff *msg, struct devlink *devlink)
+{
+	struct nlattr *nested_attr;
+
+	nested_attr = nla_nest_start(msg, DEVLINK_ATTR_NESTED_DEVLINK);
+	if (!nested_attr)
+		return -EMSGSIZE;
+	if (devlink_nl_put_handle(msg, devlink))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, nested_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, nested_attr);
+	return -EMSGSIZE;
+}
+
 struct devlink_reload_combination {
 	enum devlink_reload_action action;
 	enum devlink_reload_limit limit;
@@ -2100,6 +2119,10 @@ static int devlink_nl_linecard_fill(struct sk_buff *msg,
 		nla_nest_end(msg, attr);
 	}
 
+	if (linecard->nested_devlink &&
+	    devlink_nl_put_nested_handle(msg, linecard->nested_devlink))
+		goto nla_put_failure;
+
 	genlmsg_end(msg, hdr);
 	return 0;
 
@@ -10335,6 +10358,7 @@ EXPORT_SYMBOL_GPL(devlink_linecard_provision_set);
 void devlink_linecard_provision_clear(struct devlink_linecard *linecard)
 {
 	mutex_lock(&linecard->state_lock);
+	WARN_ON(linecard->nested_devlink);
 	linecard->state = DEVLINK_LINECARD_STATE_UNPROVISIONED;
 	linecard->type = NULL;
 	devlink_linecard_notify(linecard, DEVLINK_CMD_LINECARD_NEW);
@@ -10353,6 +10377,7 @@ EXPORT_SYMBOL_GPL(devlink_linecard_provision_clear);
 void devlink_linecard_provision_fail(struct devlink_linecard *linecard)
 {
 	mutex_lock(&linecard->state_lock);
+	WARN_ON(linecard->nested_devlink);
 	linecard->state = DEVLINK_LINECARD_STATE_PROVISIONING_FAILED;
 	devlink_linecard_notify(linecard, DEVLINK_CMD_LINECARD_NEW);
 	mutex_unlock(&linecard->state_lock);
@@ -10400,6 +10425,23 @@ void devlink_linecard_deactivate(struct devlink_linecard *linecard)
 }
 EXPORT_SYMBOL_GPL(devlink_linecard_deactivate);
 
+/**
+ *	devlink_linecard_nested_dl_set - Attach/detach nested delink
+ *					 instance to linecard.
+ *
+ *	@linecard: devlink linecard
+ *      @nested_devlink: devlink instance to attach or NULL to detach
+ */
+void devlink_linecard_nested_dl_set(struct devlink_linecard *linecard,
+				    struct devlink *nested_devlink)
+{
+	mutex_lock(&linecard->state_lock);
+	linecard->nested_devlink = nested_devlink;
+	devlink_linecard_notify(linecard, DEVLINK_CMD_LINECARD_NEW);
+	mutex_unlock(&linecard->state_lock);
+}
+EXPORT_SYMBOL_GPL(devlink_linecard_nested_dl_set);
+
 int devlink_sb_register(struct devlink *devlink, unsigned int sb_index,
 			u32 size, u16 ingress_pools_count,
 			u16 egress_pools_count, u16 ingress_tc_count,
-- 
2.35.3