On 5/22/2019 6:20 PM, Ioana Ciornei wrote:
> This adds a new entry point to PHYLINK that does not require a
> net_device structure.
>
> The main intended use are DSA ports that do not have net devices
> registered for them (mainly because doing so would be redundant - see
> Documentation/networking/dsa/dsa.rst for details). So far DSA has been
> using PHYLIB fixed PHYs for these ports, driven manually with genphy
> instead of starting a full PHY state machine, but this does not scale
> well when there are actual PHYs that need a driver on those ports, or
> when a fixed-link is requested in DT that has a speed unsupported by the
> fixed PHY C22 emulation (such as SGMII-2500).
>
> The proposed solution comes in the form of a notifier chain owned by the
> PHYLINK instance, and the passing of phylink_notifier_info structures
> back to the driver through a blocking notifier call.
>
> The event API exposed by the new notifier mechanism is a 1:1 mapping to
> the existing PHYLINK mac_ops, plus the PHYLINK fixed-link callback.
>
> Both the standard phylink_create() function, as well as its raw variant,
> call the same underlying function which initializes either the netdev
> field or the notifier block of the PHYLINK instance.
>
> All PHYLINK driver callbacks have been extended to call the notifier
> chain in case the instance is a raw one.
>
> Signed-off-by: Ioana Ciornei <ioana.cior...@nxp.com>
> Signed-off-by: Vladimir Oltean <olte...@gmail.com>
> ---
[snip]
> + struct phylink_notifier_info info = {
> + .link_an_mode = pl->link_an_mode,
> + /* Discard const pointer */
> + .state = (struct phylink_link_state *)state,
> + };
> +
> netdev_dbg(pl->netdev,
> "%s: mode=%s/%s/%s/%s adv=%*pb pause=%02x link=%u an=%u\n",
> __func__, phylink_an_mode_str(pl->link_an_mode),
> @@ -299,7 +317,12 @@ static void phylink_mac_config(struct phylink *pl,
> __ETHTOOL_LINK_MODE_MASK_NBITS, state->advertising,
> state->pause, state->link, state->an_enabled);
Don't you need to guard that netdev_dbg() with an if (pl->ops) to avoid
de-referencing a NULL net_device?
Another possibility could be to change the signature of the
phylink_mac_ops to take an opaque pointer and in the case where we
called phylink_create() and passed down a net_device pointer, we somehow
remember that for doing any operation that requires a net_device
(printing, setting carrier). We lose strict typing in doing that, but
we'd have fewer places to patch for a blocking notifier call.
--
Florian
