Re: [PATCH net-next v18 01/10] net: phy: phy_link_topology: Add a helper for opportunistic alloc
From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Date: 2026-09-28 09:36:53
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Le 27/09/2026 à 15:36, Maxime Chevallier a écrit :
The phy_link_topology structure stores information about the PHY-related components connected to a net_device. It is opportunistically allocated, when we add the first item to the topology, as this is not relevant for all kinds of net_devices. In preparation for the addition of phy_port tracking in the topology, let's make a dedicated helper for that allocation sequence. Reviewed-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Aleksei Sviridkin <redacted> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
quoted hunk ↗ jump to hunk
--- drivers/net/phy/phy_link_topology.c | 40 +++++++++++++++++++++++------ 1 file changed, 32 insertions(+), 8 deletions(-)diff --git a/drivers/net/phy/phy_link_topology.c b/drivers/net/phy/phy_link_topology.c index 4134de7ae313..0462283c8020 100644 --- a/drivers/net/phy/phy_link_topology.c +++ b/drivers/net/phy/phy_link_topology.c@@ -28,11 +28,39 @@ static int netdev_alloc_phy_link_topology(struct net_device *dev) return 0; } +static struct phy_link_topology *phy_link_topo_get_or_alloc(struct net_device *dev) +{ + int ret; + + if (dev->link_topo) + return dev->link_topo; + + /* The topology is allocated the first time we add an object to it. + * It is freed alongside the netdev. It can be called on multiple + * contexts: + * - It can be called from .probe() : No rtnl, no netdev_lock + * - .ndo_open() : rtnl and possibly netdev_lock + * - SFP state machine : rtnl held or not + * + * However, we can't really have races : + * - If we have a PHY, phy_link_topo_add_phy() will always run first + * and trigger the alloc. Only then the ports can be added through + * phylib or sfp. + * - If we don't, the SFP port for the cage is registered first, and + * only then other ports/PHYs can be registered. + */ + ret = netdev_alloc_phy_link_topology(dev); + if (ret) + return ERR_PTR(ret); + + return dev->link_topo; +} + int phy_link_topo_add_phy(struct net_device *dev, struct phy_device *phy, enum phy_upstream upt, void *upstream) { - struct phy_link_topology *topo = dev->link_topo; + struct phy_link_topology *topo; struct phy_device_node *pdn; int ret;@@ -45,13 +73,9 @@ int phy_link_topo_add_phy(struct net_device *dev, if (WARN_ON_ONCE(netdev_need_ops_lock(dev))) return -EOPNOTSUPP; - if (!topo) { - ret = netdev_alloc_phy_link_topology(dev); - if (ret) - return ret; - - topo = dev->link_topo; - } + topo = phy_link_topo_get_or_alloc(dev); + if (IS_ERR(topo)) + return PTR_ERR(topo); pdn = kzalloc_obj(*pdn); if (!pdn)