Subject: Re: [PATCH net-next 2/4] net: mvpp2: add mvpp2_phylink_to_port() helper

From: Sasha Levin <[email-masked]>
Date: Tue, 8 Dec 2020 08:35:32 -0500

On Tue, Dec 08, 2020 at 01:03:38PM +0100, Marcin Wojtas wrote:
>Hi Greg,
>
>Apologies for delayed response:.
>
>
>pon., 2 lis 2020 o 19:02 Greg Kroah-Hartman
><[email-masked]> napisał(a):
>>
>> On Mon, Nov 02, 2020 at 06:38:54PM +0100, Marcin Wojtas wrote:
>> > Hi Greg and Sasha,
>> >
>> > pt., 9 paź 2020 o 05:43 Marcin Wojtas <[email-masked]> napisał(a):
>> > >
>> > > Hi,
>> > >
>> > > sob., 20 cze 2020 o 11:21 Russell King <[email-masked]> napisał(a):
>> > > >
>> > > > Add a helper to convert the struct phylink_config pointer passed in
>> > > > from phylink to the drivers internal struct mvpp2_port.
>> > > >
>> > > > Signed-off-by: Russell King <[email-masked]>
>> > > > ---
>> > > >  .../net/ethernet/marvell/mvpp2/mvpp2_main.c   | 29 +++++++++----------
>> > > >  1 file changed, 14 insertions(+), 15 deletions(-)
>> > > >
>> > > > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
>> > > > index 7653277d03b7..313f5a60a605 100644
>> > > > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
>> > > > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
>> > > > @@ -4767,12 +4767,16 @@ static void mvpp2_port_copy_mac_addr(struct net_device *dev, struct mvpp2 *priv,
>> > > >         eth_hw_addr_random(dev);
>> > > >  }
>> > > >
>> > > > +static struct mvpp2_port *mvpp2_phylink_to_port(struct phylink_config *config)
>> > > > +{
>> > > > +       return container_of(config, struct mvpp2_port, phylink_config);
>> > > > +}
>> > > > +
>> > > >  static void mvpp2_phylink_validate(struct phylink_config *config,
>> > > >                                    unsigned long *supported,
>> > > >                                    struct phylink_link_state *state)
>> > > >  {
>> > > > -       struct mvpp2_port *port = container_of(config, struct mvpp2_port,
>> > > > -                                              phylink_config);
>> > > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
>> > > >         __ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
>> > > >
>> > > >         /* Invalid combinations */
>> > > > @@ -4913,8 +4917,7 @@ static void mvpp2_gmac_pcs_get_state(struct mvpp2_port *port,
>> > > >  static void mvpp2_phylink_mac_pcs_get_state(struct phylink_config *config,
>> > > >                                             struct phylink_link_state *state)
>> > > >  {
>> > > > -       struct mvpp2_port *port = container_of(config, struct mvpp2_port,
>> > > > -                                              phylink_config);
>> > > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
>> > > >
>> > > >         if (port->priv->hw_version == MVPP22 && port->gop_id == 0) {
>> > > >                 u32 mode = readl(port->base + MVPP22_XLG_CTRL3_REG);
>> > > > @@ -4931,8 +4934,7 @@ static void mvpp2_phylink_mac_pcs_get_state(struct phylink_config *config,
>> > > >
>> > > >  static void mvpp2_mac_an_restart(struct phylink_config *config)
>> > > >  {
>> > > > -       struct mvpp2_port *port = container_of(config, struct mvpp2_port,
>> > > > -                                              phylink_config);
>> > > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
>> > > >         u32 val = readl(port->base + MVPP2_GMAC_AUTONEG_CONFIG);
>> > > >
>> > > >         writel(val | MVPP2_GMAC_IN_BAND_RESTART_AN,
>> > > > @@ -5105,13 +5107,12 @@ static void mvpp2_gmac_config(struct mvpp2_port *port, unsigned int mode,
>> > > >  static void mvpp2_mac_config(struct phylink_config *config, unsigned int mode,
>> > > >                              const struct phylink_link_state *state)
>> > > >  {
>> > > > -       struct net_device *dev = to_net_dev(config->dev);
>> > > > -       struct mvpp2_port *port = netdev_priv(dev);
>> > > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
>> > > >         bool change_interface = port->phy_interface != state->interface;
>> > > >
>> > > >         /* Check for invalid configuration */
>> > > >         if (mvpp2_is_xlg(state->interface) && port->gop_id != 0) {
>> > > > -               netdev_err(dev, "Invalid mode on %s\n", dev->name);
>> > > > +               netdev_err(port->dev, "Invalid mode on %s\n", port->dev->name);
>> > > >                 return;
>> > > >         }
>> > > >
>> > > > @@ -5151,8 +5152,7 @@ static void mvpp2_mac_link_up(struct phylink_config *config,
>> > > >                               int speed, int duplex,
>> > > >                               bool tx_pause, bool rx_pause)
>> > > >  {
>> > > > -       struct net_device *dev = to_net_dev(config->dev);
>> > > > -       struct mvpp2_port *port = netdev_priv(dev);
>> > > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
>> > > >         u32 val;
>> > > >
>> > > >         if (mvpp2_is_xlg(interface)) {
>> > > > @@ -5199,14 +5199,13 @@ static void mvpp2_mac_link_up(struct phylink_config *config,
>> > > >
>> > > >         mvpp2_egress_enable(port);
>> > > >         mvpp2_ingress_enable(port);
>> > > > -       netif_tx_wake_all_queues(dev);
>> > > > +       netif_tx_wake_all_queues(port->dev);
>> > > >  }
>> > > >
>> > > >  static void mvpp2_mac_link_down(struct phylink_config *config,
>> > > >                                 unsigned int mode, phy_interface_t interface)
>> > > >  {
>> > > > -       struct net_device *dev = to_net_dev(config->dev);
>> > > > -       struct mvpp2_port *port = netdev_priv(dev);
>> > > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
>> > > >         u32 val;
>> > > >
>> > > >         if (!phylink_autoneg_inband(mode)) {
>> > > > @@ -5223,7 +5222,7 @@ static void mvpp2_mac_link_down(struct phylink_config *config,
>> > > >                 }
>> > > >         }
>> > > >
>> > > > -       netif_tx_stop_all_queues(dev);
>> > > > +       netif_tx_stop_all_queues(port->dev);
>> > > >         mvpp2_egress_disable(port);
>> > > >         mvpp2_ingress_disable(port);
>> > > >
>> > > > --
>> > > > 2.20.1
>> > > >
>> > >
>> > > This patch fixes a regression that was introduced in v5.3:
>> > > Commit 44cc27e43fa3 ("net: phylink: Add struct phylink_config to PHYLINK API")
>> > >
>> > > Above results in a NULL pointer dereference when booting the
>> > > Armada7k8k/CN913x with ACPI between 5.3 and 5.8, which will be
>> > > problematic especially for the distros using LTSv5.4 and above (the
>> > > issue was reported on Fedora 32).
>> > >
>> > > Please help with backporting to the stable v5.3+ branches (it applies
>> > > smoothly on v5.4/v5.6/v5.8).
>> > >
>> >
>> > Any chances to backport this patch to relevant v5.3+ stable branches?
>>
>> What patch?  What git commit id needs to be backported?
>>
>
>The actual patch is:
>Commit 6c2b49eb9671  ("net: mvpp2: add mvpp2_phylink_to_port() helper").
>
>URL for reference:
>https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/ethernet/marvell/mvpp2?h=v5.10-rc7&id=6c2b49eb96716e91f202756bfbd3f5fea3b2b172
>
>Do you think it would be possible to get it merged to v5.3+ stable branches?

Could you explain how that patch fixes anything? It reads like a
cleanup.

-- 
Thanks,
Sasha