[net-next,3/4] devlink: expose peer SF devlink instance

Commit Message

Jiri Pirko Aug. 15, 2023, 2:51 p.m. UTC

From: Jiri Pirko <[e-mail]>

Introduce a new helper devl_port_fn_devlink_set() to be used by driver
assigning a devlink instance to the peer devlink port function.

Expose this to user over new netlink attribute nested under port
function nest to expose devlink handle related to the port function.

This is particularly helpful for user to understand the relationship
between devlink instances created for SFs and the port functions
they belong to.

Note that caller of devlink_port_notify() needs to hold devlink
instance lock, put the assertion to devl_port_fn_devlink_set() to make
this requirement explicit. Also note the limitations that only allow to
make this assignment for registered objects.

Signed-off-by: Jiri Pirko <[e-mail]>
---
 include/net/devlink.h        |  4 ++++
 include/uapi/linux/devlink.h |  1 +
 net/devlink/leftover.c       | 45 +++++++++++++++++++++++++++++++++---
 3 files changed, 47 insertions(+), 3 deletions(-)

Patch

diff --git a/include/net/devlink.h b/include/net/devlink.h
index f7fec0791acc..49662d44471c 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -150,6 +150,8 @@  struct devlink_port {
 
 	struct devlink_rate *devlink_rate;
 	struct devlink_linecard *linecard;
+
+	struct devlink *fn_devlink; /* Peer function devlink instance */
 };
 
 struct devlink_port_new_attrs {
@@ -1667,6 +1669,8 @@  void devlink_port_attrs_pci_vf_set(struct devlink_port *devlink_port, u32 contro
 void devlink_port_attrs_pci_sf_set(struct devlink_port *devlink_port,
 				   u32 controller, u16 pf, u32 sf,
 				   bool external);
+void devl_port_fn_devlink_set(struct devlink_port *devlink_port,
+			      struct devlink *fn_devlink);
 struct devlink_rate *
 devl_rate_node_create(struct devlink *devlink, void *priv, char *node_name,
 		      struct devlink_rate *parent);
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 3782d4219ac9..dd96086860ca 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -676,6 +676,7 @@  enum devlink_port_function_attr {
 	DEVLINK_PORT_FN_ATTR_STATE,	/* u8 */
 	DEVLINK_PORT_FN_ATTR_OPSTATE,	/* u8 */
 	DEVLINK_PORT_FN_ATTR_CAPS,	/* bitfield32 */
+	DEVLINK_PORT_FN_ATTR_DEVLINK,	/* nested */
 
 	__DEVLINK_PORT_FUNCTION_ATTR_MAX,
 	DEVLINK_PORT_FUNCTION_ATTR_MAX = __DEVLINK_PORT_FUNCTION_ATTR_MAX - 1
diff --git a/net/devlink/leftover.c b/net/devlink/leftover.c
index 3883a90d32bb..89172c5e3eaa 100644
--- a/net/devlink/leftover.c
+++ b/net/devlink/leftover.c
@@ -591,11 +591,12 @@  devlink_region_snapshot_get_by_id(struct devlink_region *region, u32 id)
 	return NULL;
 }
 
-static int devlink_nl_put_nested_handle(struct sk_buff *msg, struct devlink *devlink)
+static int devlink_nl_put_nested_handle(struct sk_buff *msg, struct devlink *devlink,
+					int attrtype)
 {
 	struct nlattr *nested_attr;
 
-	nested_attr = nla_nest_start(msg, DEVLINK_ATTR_NESTED_DEVLINK);
+	nested_attr = nla_nest_start(msg, attrtype);
 	if (!nested_attr)
 		return -EMSGSIZE;
 	if (devlink_nl_put_handle(msg, devlink))
@@ -884,6 +885,15 @@  devlink_nl_port_function_attrs_put(struct sk_buff *msg, struct devlink_port *por
 	if (err)
 		goto out;
 	err = devlink_port_fn_state_fill(port, msg, extack, &msg_updated);
+	if (err)
+		goto out;
+	if (port->fn_devlink) {
+		err = devlink_nl_put_nested_handle(msg, port->fn_devlink,
+						   DEVLINK_PORT_FN_ATTR_DEVLINK);
+		if (!err)
+			msg_updated = true;
+	}
+
 out:
 	if (err || !msg_updated)
 		nla_nest_cancel(msg, function_attr);
@@ -1785,7 +1795,8 @@  static int devlink_nl_linecard_fill(struct sk_buff *msg,
 	}
 
 	if (linecard->nested_devlink &&
-	    devlink_nl_put_nested_handle(msg, linecard->nested_devlink))
+	    devlink_nl_put_nested_handle(msg, linecard->nested_devlink,
+					 DEVLINK_ATTR_NESTED_DEVLINK))
 		goto nla_put_failure;
 
 	genlmsg_end(msg, hdr);
@@ -7133,6 +7144,34 @@  void devlink_port_attrs_pci_sf_set(struct devlink_port *devlink_port, u32 contro
 }
 EXPORT_SYMBOL_GPL(devlink_port_attrs_pci_sf_set);
 
+/**
+ * devl_port_fn_devlink_set - Attach/detach peer devlink
+ *			      instance to port function.
+ * @devlink_port: devlink port
+ * @fn_devlink: devlink instance to attach or NULL to detach
+ */
+void devl_port_fn_devlink_set(struct devlink_port *devlink_port,
+			      struct devlink *fn_devlink)
+{
+	lockdep_assert_held(&devlink_port->devlink->lock);
+	ASSERT_DEVLINK_PORT_REGISTERED(devlink_port);
+
+	if (fn_devlink)
+		ASSERT_DEVLINK_REGISTERED(fn_devlink);
+	else if (WARN_ON(!devlink_port->fn_devlink))
+		return;
+	else
+		ASSERT_DEVLINK_REGISTERED(devlink_port->fn_devlink);
+
+	if (WARN_ON(devlink_port->attrs.flavour != DEVLINK_PORT_FLAVOUR_PCI_SF ||
+		    devlink_port->attrs.pci_sf.external))
+		return;
+
+	devlink_port->fn_devlink = fn_devlink;
+	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
+}
+EXPORT_SYMBOL_GPL(devl_port_fn_devlink_set);
+
 /**
  * devl_rate_node_create - create devlink rate node
  * @devlink: devlink instance