Re: [PATCH net-next v2 3/7] net: dsa: Register devlink ports before calling DSA driver setup()

Vladimir Oltean
2020-09-26T23:41:56Z

On Sat, Sep 26, 2020 at 11:06:28PM +0200, Andrew Lunn wrote:
> DSA drivers want to create regions on devlink ports as well as the
> devlink device instance, in order to export registers and other tables
> per port. To keep all this code together in the drivers, have the
> devlink ports registered early, so the setup() method can setup both
> device and port devlink regions.
>
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> ---
> include/net/dsa.h | 1 +
> net/dsa/dsa2.c | 133 ++++++++++++++++++++++++++++------------------
> 2 files changed, 83 insertions(+), 51 deletions(-)
>
> diff --git a/include/net/dsa.h b/include/net/dsa.h
> index d16057c5987a..9aa44dc8ecdb 100644
> --- a/include/net/dsa.h
> +++ b/include/net/dsa.h
> @@ -208,6 +208,7 @@ struct dsa_port {
> u8 stp_state;
> struct net_device *bridge_dev;
> struct devlink_port devlink_port;
> + bool devlink_port_setup;
> struct phylink *pl;
> struct phylink_config pl_config;
>
> diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
> index 2c149fb36928..90cc70bd7c22 100644
> --- a/net/dsa/dsa2.c
> +++ b/net/dsa/dsa2.c
> @@ -251,47 +251,19 @@ static void dsa_tree_teardown_default_cpu(struct dsa_switch_tree *dst)
>
> static int dsa_port_setup(struct dsa_port *dp)
> {
> - struct dsa_switch *ds = dp->ds;
> - struct dsa_switch_tree *dst = ds->dst;
> - const unsigned char *id = (const unsigned char *)&dst->index;
> - const unsigned char len = sizeof(dst->index);
> struct devlink_port *dlp = &dp->devlink_port;
> bool dsa_port_link_registered = false;
> - bool devlink_port_registered = false;
> - struct devlink_port_attrs attrs = {};
> - struct devlink *dl = ds->devlink;
> bool dsa_port_enabled = false;
> int err = 0;
>
> - attrs.phys.port_number = dp->index;
> - memcpy(attrs.switch_id.id, id, len);
> - attrs.switch_id.id_len = len;
> -
> if (dp->setup)
> return 0;
>
> switch (dp->type) {
> case DSA_PORT_TYPE_UNUSED:
> - memset(dlp, 0, sizeof(*dlp));
> - attrs.flavour = DEVLINK_PORT_FLAVOUR_UNUSED;
> - devlink_port_attrs_set(dlp, &attrs);
> - err = devlink_port_register(dl, dlp, dp->index);
> - if (err)
> - break;
> -
> - devlink_port_registered = true;
> -
> dsa_port_disable(dp);
> break;
> case DSA_PORT_TYPE_CPU:
> - memset(dlp, 0, sizeof(*dlp));
> - attrs.flavour = DEVLINK_PORT_FLAVOUR_CPU;
> - devlink_port_attrs_set(dlp, &attrs);
> - err = devlink_port_register(dl, dlp, dp->index);
> - if (err)
> - break;
> - devlink_port_registered = true;
> -
> err = dsa_port_link_register_of(dp);
> if (err)
> break;
> @@ -304,14 +276,6 @@ static int dsa_port_setup(struct dsa_port *dp)
>
> break;
> case DSA_PORT_TYPE_DSA:
> - memset(dlp, 0, sizeof(*dlp));
> - attrs.flavour = DEVLINK_PORT_FLAVOUR_DSA;
> - devlink_port_attrs_set(dlp, &attrs);
> - err = devlink_port_register(dl, dlp, dp->index);
> - if (err)
> - break;
> - devlink_port_registered = true;
> -
> err = dsa_port_link_register_of(dp);
> if (err)
> break;
> @@ -324,14 +288,6 @@ static int dsa_port_setup(struct dsa_port *dp)
>
> break;
> case DSA_PORT_TYPE_USER:
> - memset(dlp, 0, sizeof(*dlp));
> - attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
> - devlink_port_attrs_set(dlp, &attrs);
> - err = devlink_port_register(dl, dlp, dp->index);
> - if (err)
> - break;
> - devlink_port_registered = true;
> -
> dp->mac = of_get_mac_address(dp->dn);
> err = dsa_slave_create(dp);
> if (err)
> @@ -345,8 +301,6 @@ static int dsa_port_setup(struct dsa_port *dp)
> dsa_port_disable(dp);
> if (err && dsa_port_link_registered)
> dsa_port_link_unregister_of(dp);
> - if (err && devlink_port_registered)
> - devlink_port_unregister(dlp);
> if (err)
> return err;
>
> @@ -355,30 +309,77 @@ static int dsa_port_setup(struct dsa_port *dp)
> return 0;
> }
>
> -static void dsa_port_teardown(struct dsa_port *dp)
> +static int dsa_port_devlink_setup(struct dsa_port *dp)
> {
> struct devlink_port *dlp = &dp->devlink_port;
> + struct dsa_switch_tree *dst = dp->ds->dst;
> + struct devlink_port_attrs attrs = {};
> + struct devlink *dl = dp->ds->devlink;
> + const unsigned char *id;
> + unsigned char len;
> + int err;
> +
> + id = (const unsigned char *)&dst->index;
> + len = sizeof(dst->index);
> +
> + attrs.phys.port_number = dp->index;
> + memcpy(attrs.switch_id.id, id, len);
> + attrs.switch_id.id_len = len;
> +
> + if (dp->setup)
> + return 0;
>

I wonder what this is protecting against? I ran on a multi-switch tree
without these 2 lines and I didn't get anything like multiple
registration or things like that. What is the call path that would call
dsa_port_devlink_setup twice?

> + switch (dp->type) {
> + case DSA_PORT_TYPE_UNUSED:
> + memset(dlp, 0, sizeof(*dlp));
> + attrs.flavour = DEVLINK_PORT_FLAVOUR_UNUSED;

> + devlink_port_attrs_set(dlp, &attrs);
> + err = devlink_port_register(dl, dlp, dp->index);

These 2 lines are common everywhere. Could you move them out of the
switch-case statement?

> + break;
> + case DSA_PORT_TYPE_CPU:
> + memset(dlp, 0, sizeof(*dlp));
> + attrs.flavour = DEVLINK_PORT_FLAVOUR_CPU;
> + devlink_port_attrs_set(dlp, &attrs);
> + err = devlink_port_register(dl, dlp, dp->index);
> + break;
> + case DSA_PORT_TYPE_DSA:
> + memset(dlp, 0, sizeof(*dlp));
> + attrs.flavour = DEVLINK_PORT_FLAVOUR_DSA;
> + devlink_port_attrs_set(dlp, &attrs);
> + err = devlink_port_register(dl, dlp, dp->index);
> + break;
> + case DSA_PORT_TYPE_USER:
> + memset(dlp, 0, sizeof(*dlp));
> + attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
> + devlink_port_attrs_set(dlp, &attrs);
> + err = devlink_port_register(dl, dlp, dp->index);
> + break;
> + }
> +
> + if (!err)
> + dp->devlink_port_setup = true;
> +
> + return err;
> +}
> +
> +static void dsa_port_teardown(struct dsa_port *dp)
> +{
> if (!dp->setup)
> return;
>
> switch (dp->type) {
> case DSA_PORT_TYPE_UNUSED:
> - devlink_port_unregister(dlp);
> break;
> case DSA_PORT_TYPE_CPU:
> dsa_port_disable(dp);
> dsa_tag_driver_put(dp->tag_ops);
> - devlink_port_unregister(dlp);
> dsa_port_link_unregister_of(dp);
> break;
> case DSA_PORT_TYPE_DSA:
> dsa_port_disable(dp);
> - devlink_port_unregister(dlp);
> dsa_port_link_unregister_of(dp);
> break;
> case DSA_PORT_TYPE_USER:
> - devlink_port_unregister(dlp);
> if (dp->slave) {
> dsa_slave_destroy(dp->slave);
> dp->slave = NULL;
> @@ -389,6 +390,15 @@ static void dsa_port_teardown(struct dsa_port *dp)
> dp->setup = false;
> }
>
> +static void dsa_port_devlink_teardown(struct dsa_port *dp)
> +{
> + struct devlink_port *dlp = &dp->devlink_port;
> +
> + if (dp->devlink_port_setup)
> + devlink_port_unregister(dlp);
> + dp->devlink_port_setup = false;
> +}
> +
> static int dsa_devlink_info_get(struct devlink *dl,
> struct devlink_info_req *req,
> struct netlink_ext_ack *extack)
> @@ -408,6 +418,7 @@ static const struct devlink_ops dsa_devlink_ops = {
> static int dsa_switch_setup(struct dsa_switch *ds)
> {
> struct dsa_devlink_priv *dl_priv;
> + struct dsa_port *dp;
> int err;
>
> if (ds->setup)
> @@ -433,6 +444,17 @@ static int dsa_switch_setup(struct dsa_switch *ds)
> if (err)
> goto free_devlink;
>
> + /* Setup devlink port instances now, so that the switch
> + * setup() can register regions etc, against the ports
> + */
> + list_for_each_entry(dp, &ds->dst->ports, list) {
> + if (dp->ds == ds) {
> + err = dsa_port_devlink_setup(dp);
> + if (err)
> + goto unregister_devlink_ports;
> + }
> + }
> +
> err = dsa_switch_register_notifier(ds);
> if (err)
> goto unregister_devlink;

Need to use goto unregister_devlink_ports here.

> @@ -463,6 +485,10 @@ static int dsa_switch_setup(struct dsa_switch *ds)
>
> unregister_notifier:
> dsa_switch_unregister_notifier(ds);
> +unregister_devlink_ports:
> + list_for_each_entry(dp, &ds->dst->ports, list)
> + if (dp->ds == ds)
> + dsa_port_devlink_teardown(dp);
> unregister_devlink:
> devlink_unregister(ds->devlink);
> free_devlink:
> @@ -474,6 +500,8 @@ static int dsa_switch_setup(struct dsa_switch *ds)
>
> static void dsa_switch_teardown(struct dsa_switch *ds)
> {
> + struct dsa_port *dp;
> +
> if (!ds->setup)
> return;
>
> @@ -486,6 +514,9 @@ static void dsa_switch_teardown(struct dsa_switch *ds)
> ds->ops->teardown(ds);
>
> if (ds->devlink) {
> + list_for_each_entry(dp, &ds->dst->ports, list)
> + if (dp->ds == ds)
> + dsa_port_devlink_teardown(dp);
> devlink_unregister(ds->devlink);
> devlink_free(ds->devlink);
> ds->devlink = NULL;
> --
> 2.28.0
>