Re: [PATCH v2 net] net: phy: clear phydev->devlink when the link is deleted

[Russell King (Oracle)]

On Wed, Jun 04, 2025 at 06:00:54AM +0000, Wei Fang wrote:
> I think this issue is also introduced by the commit bc66fa87d4fd
> ("net: phy: Add link between phy dev and mac dev"). I suggested
> to change the DL_FLAG_STATELESS flag to
> DL_FLAG_AUTOREMOVE_SUPPLIER to solve this issue, so that
> the consumer (MAC controller) driver will be automatically removed
> when the link is removed. The changes are as follows.

I suspect this still has problems. This is fine if the PHY device is
going away and as you say device_del() is called.

However, you need to consider the case where a MAC driver attaches the
PHY during .ndo_open and releases it during .ndo_release. These will
happen multiple times.

Each time the MAC driver attaches to the PHY via .ndo_open, we will
call device_link_add(), but the device link will not be removed when
.ndo_release is called.

Either device_link_add() will fail, or we will eat memory each time
the device is closed and re-opened.

If that is correct, then we're trading one problem for another.

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