Re: [PATCH net-next v2 7/7] net: dsa: mv88e6xxx: Add per port devlink regions

Vladimir Oltean
2020-09-26T23:52:53Z

On Sat, Sep 26, 2020 at 11:06:32PM +0200, Andrew Lunn wrote:
> Add a devlink region to return the per port registers.
>
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> ---
> drivers/net/dsa/mv88e6xxx/devlink.c | 109 +++++++++++++++++++++++++++-
> 1 file changed, 105 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/dsa/mv88e6xxx/devlink.c b/drivers/net/dsa/mv88e6xxx/devlink.c
> index 81e1560db206..ed74b075de84 100644
> --- a/drivers/net/dsa/mv88e6xxx/devlink.c
> +++ b/drivers/net/dsa/mv88e6xxx/devlink.c
> @@ -415,6 +415,36 @@ static int mv88e6xxx_region_atu_snapshot(struct devlink *dl,
> return err;
> }
>
> +static int mv88e6xxx_region_port_snapshot(struct devlink_port *devlink_port,
> + const struct devlink_port_region_ops *ops,
> + struct netlink_ext_ack *extack,
> + u8 **data)
> +{
> + struct dsa_switch *ds = dsa_devlink_port_to_ds(devlink_port);
> + int port = dsa_devlink_port_to_port(devlink_port);
> + struct mv88e6xxx_chip *chip = ds->priv;

> + u16 *registers;

I was meaning to ask this since the global regions patchset, but I
forgot.

Do we not expect to see, under the same circumstances, the same region
snapshot on a big endian and on a little endian system?

> + int i, err;
> +
> + registers = kmalloc_array(32, sizeof(u16), GFP_KERNEL);
> + if (!registers)
> + return -ENOMEM;
> +
> + mv88e6xxx_reg_lock(chip);
> + for (i = 0; i < 32; i++) {
> + err = mv88e6xxx_port_read(chip, port, i, &registers[i]);
> + if (err) {
> + kfree(registers);
> + goto out;
> + }
> + }
> + *data = (u8 *)registers;
> +out:
> + mv88e6xxx_reg_unlock(chip);
> +
> + return err;
> +}
> +
> static struct mv88e6xxx_region_priv mv88e6xxx_region_global1_priv = {
> .id = MV88E6XXX_REGION_GLOBAL1,
> };
> @@ -443,6 +473,12 @@ static struct devlink_region_ops mv88e6xxx_region_atu_ops = {
> .destructor = kfree,
> };
>
> +static const struct devlink_port_region_ops mv88e6xxx_region_port_ops = {
> + .name = "port",
> + .snapshot = mv88e6xxx_region_port_snapshot,
> + .destructor = kfree,
> +};
> +
> struct mv88e6xxx_region {
> struct devlink_region_ops *ops;
> u64 size;
> @@ -471,11 +507,59 @@ mv88e6xxx_teardown_devlink_regions_global(struct mv88e6xxx_chip *chip)
> dsa_devlink_region_destroy(chip->regions[i]);
> }
>
> -void mv88e6xxx_teardown_devlink_regions(struct dsa_switch *ds)
> +static void
> +mv88e6xxx_teardown_devlink_regions_port(struct mv88e6xxx_chip *chip,
> + int port)
> {
> - struct mv88e6xxx_chip *chip = ds->priv;
> + dsa_devlink_region_destroy(chip->ports[port].region);
> +}
>
> - mv88e6xxx_teardown_devlink_regions_global(chip);
> +static int mv88e6xxx_setup_devlink_regions_port(struct dsa_switch *ds,
> + struct mv88e6xxx_chip *chip,
> + int port)
> +{
> + struct devlink_region *region;
> +
> + region = dsa_devlink_port_region_create(ds,
> + port,
> + &mv88e6xxx_region_port_ops, 1,
> + 32 * sizeof(u16));
> + if (IS_ERR(region))
> + return PTR_ERR(region);
> +
> + chip->ports[port].region = region;
> +
> + return 0;
> +}
> +
> +static void
> +mv88e6xxx_teardown_devlink_regions_ports(struct mv88e6xxx_chip *chip)
> +{
> + int port;
> +
> + for (port = 0; port < mv88e6xxx_num_ports(chip); port++)
> + mv88e6xxx_teardown_devlink_regions_port(chip, port);
> +}
> +
> +static int mv88e6xxx_setup_devlink_regions_ports(struct dsa_switch *ds,
> + struct mv88e6xxx_chip *chip)
> +{
> + int port, port_err;
> + int err;
> +
> + for (port = 0; port < mv88e6xxx_num_ports(chip); port++) {
> + err = mv88e6xxx_setup_devlink_regions_port(ds, chip, port);
> + if (err)
> + goto out;
> + }
> +
> + return 0;
> +
> +out:
> + for (port_err = 0; port_err < port; port_err++)

"while (port-- >= 0)" should do the trick. Also, maybe it would be
overall more aesthetic if you wouldn't use the goto and have 2 exit
points in such a small function, but a simple break here. Like this:

int err;

for (port = 0; port < mv88e6xxx_num_ports(chip); port++) {
err = mv88e6xxx_setup_devlink_regions_port(ds, chip, port);
if (err) {
while (port-- >= 0)
mv88e6xxx_teardown_devlink_regions_port(chip,
port);
break;
}
}

return err;

> + mv88e6xxx_teardown_devlink_regions_port(chip, port_err);
> +
> + return err;
> }
>
> static int mv88e6xxx_setup_devlink_regions_global(struct dsa_switch *ds,
> @@ -511,8 +595,25 @@ static int mv88e6xxx_setup_devlink_regions_global(struct dsa_switch *ds,
> int mv88e6xxx_setup_devlink_regions(struct dsa_switch *ds)
> {
> struct mv88e6xxx_chip *chip = ds->priv;
> + int err;
> +
> + err = mv88e6xxx_setup_devlink_regions_global(ds, chip);
> + if (err)
> + return err;
> +
> + err = mv88e6xxx_setup_devlink_regions_ports(ds, chip);
> + if (err)
> + mv88e6xxx_teardown_devlink_regions_global(chip);
>
> - return mv88e6xxx_setup_devlink_regions_global(ds, chip);
> + return err;
> +}
> +
> +void mv88e6xxx_teardown_devlink_regions(struct dsa_switch *ds)
> +{
> + struct mv88e6xxx_chip *chip = ds->priv;
> +
> + mv88e6xxx_teardown_devlink_regions_ports(chip);
> + mv88e6xxx_teardown_devlink_regions_global(chip);
> }
>
> int mv88e6xxx_devlink_info_get(struct dsa_switch *ds,
> --
> 2.28.0
>