On Fri, May 26, 2023 at 02:21:23PM +0800, Jiawen Wu wrote:
> On Friday, May 26, 2023 12:14 PM, Jakub Kicinski wrote:
> > On Wed, 24 May 2023 17:17:21 +0800 Jiawen Wu wrote:
> > > + ret = devm_mdiobus_register(&pdev->dev, mii_bus);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + mdiodev = mdio_device_create(mii_bus, 0);
> > > + if (IS_ERR(mdiodev))
> > > + return PTR_ERR(mdiodev);
> > > +
> > > + xpcs = xpcs_create(mdiodev, PHY_INTERFACE_MODE_10GBASER);
> > > + if (IS_ERR(xpcs)) {
> > > + mdio_device_free(mdiodev);
> > > + return PTR_ERR(xpcs);
> > > + }
> >
> > How does the mdiodev get destroyed in case of success?
> > Seems like either freeing it in case of xpcs error is unnecessary
> > or it needs to also be freed when xpcs is destroyed?
>
> When xpcs is destroyed, that means mdiodev is no longer needed.
> I think there is no need to free mdiodev in case of xpcs error,
> since devm_* function leads to free it.
If you are relying on the devm-ness of devm_mdiobus_register() then
it won't. Although mdiobus_unregister() walks bus->mdio_map[], I
think you are assuming that the mdio device you've created in
mdio_device_create() will be in that array. MDIO devices only get
added to that array when mdiobus_register_device() has been called,
which must only be called from mdio_device_register().
Please arrange to call mdio_device_free() prior to destroying the
XPCS in every case.
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