Re: [RFC] net: core: devlink: add port_params_ops for devlink port parameters altering

From: Vadym Kochan
Date: Fri Apr 09 2021 - 13:01:24 EST

Hi Sridhar,

On Fri, Apr 09, 2021 at 09:51:13AM -0700, Samudrala, Sridhar wrote:
> On 4/9/2021 9:22 AM, Oleksandr Mazur wrote:
> > I'd like to discuss a possibility of handling devlink port parameters
> > with devlink port pointer supplied.
> >
> > Current design makes it impossible to distinguish which port's parameter
> > should get altered (set) or retrieved (get) whenever there's a single
> > parameter registered within a few ports.
>
> I also noticed this issue recently when trying to add port parameters and
> I have a patch that handles this in a different way. The ops in devlink_param
> struct can be updated to include port_index as an argument
>

We were thinking on this direction but rather decided to have more strict
cb signature which reflects that we are working with devlink_port only.

> devlink: Fix devlink_param function pointers
>
> devlink_param function pointers are used to register device parameters
> as well as port parameters. So we need port_index also as an argument
> to enable port specific parameters.
>
> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@xxxxxxxxx>
>
> diff --git a/include/net/devlink.h b/include/net/devlink.h
> index 57251d12b0fc..bf55acdf98ae 100644
> --- a/include/net/devlink.h
> +++ b/include/net/devlink.h
> @@ -469,12 +469,12 @@ struct devlink_param {
> bool generic;
> enum devlink_param_type type;
> unsigned long supported_cmodes;
> - int (*get)(struct devlink *devlink, u32 id,
> - struct devlink_param_gset_ctx *ctx);
> - int (*set)(struct devlink *devlink, u32 id,
> - struct devlink_param_gset_ctx *ctx);
> - int (*validate)(struct devlink *devlink, u32 id,
> - union devlink_param_value val,
> + int (*get)(struct devlink *devlink, unsigned int port_index,
> + u32 id, struct devlink_param_gset_ctx *ctx);
> + int (*set)(struct devlink *devlink, unsigned int port_index,
> + u32 id, struct devlink_param_gset_ctx *ctx);
> + int (*validate)(struct devlink *devlink, unsigned int port_index,
> + u32 id, union devlink_param_value val,
> struct netlink_ext_ack *extack);
> };
>
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index 151f60af0c4a..65a819ead3d9 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -3826,21 +3826,23 @@ devlink_param_cmode_is_supported(const struct devlink_param *param,
> }
>
> static int devlink_param_get(struct devlink *devlink,
> + unsigned int port_index,
> const struct devlink_param *param,
> struct devlink_param_gset_ctx *ctx)
> {
> if (!param->get)
> return -EOPNOTSUPP;
> - return param->get(devlink, param->id, ctx);
> + return param->get(devlink, port_index, param->id, ctx);
> }
>
> static int devlink_param_set(struct devlink *devlink,
> + unsigned int port_index,
> const struct devlink_param *param,
> struct devlink_param_gset_ctx *ctx)
> {
> if (!param->set)
> return -EOPNOTSUPP;
> - return param->set(devlink, param->id, ctx);
> + return param->set(devlink, port_index, param->id, ctx);
> }
>
> static int
> @@ -3941,7 +3943,8 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
> if (!param_item->published)
> continue;
> ctx.cmode = i;
> - err = devlink_param_get(devlink, param, &ctx);
> + err = devlink_param_get(devlink, port_index, param,
> + &ctx);
> if (err)
> return err;
> param_value[i] = ctx.val;
> @@ -4216,7 +4219,8 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
> if (err)
> return err;
> if (param->validate) {
> - err = param->validate(devlink, param->id, value, info->extack);
> + err = param->validate(devlink, port_index, param->id, value,
> + info->extack);
> if (err)
> return err;
> }
> @@ -4238,7 +4242,7 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
> return -EOPNOTSUPP;
> ctx.val = value;
> ctx.cmode = cmode;
> - err = devlink_param_set(devlink, param, &ctx);
> + err = devlink_param_set(devlink, port_index, param, &ctx);
> if (err)
> return err;
> }
>
> >
> > This patch aims to show how this can be changed:
> > - introduce structure port_params_ops that has callbacks for get/set/validate;
> > - if devlink has registered port_params_ops, then upon every devlink
> > port parameter get/set call invoke port parameters callback
> >
> > Signed-off-by: Oleksandr Mazur <oleksandr.mazur@xxxxxxxxxxx>
> > ---
> > drivers/net/netdevsim/dev.c | 46 +++++++++++++++++++++++++++++++
> > drivers/net/netdevsim/netdevsim.h | 1 +
> > include/net/devlink.h | 11 ++++++++
> > net/core/devlink.c | 16 ++++++++++-
> > 4 files changed, 73 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
> > index 6189a4c0d39e..4f9a3104ca46 100644
> > --- a/drivers/net/netdevsim/dev.c
> > +++ b/drivers/net/netdevsim/dev.c
> > @@ -39,6 +39,11 @@ static struct dentry *nsim_dev_ddir;
> > #define NSIM_DEV_DUMMY_REGION_SIZE (1024 * 32)
> > +static int nsim_dev_port_param_set(struct devlink_port *port, u32 id,
> > + struct devlink_param_gset_ctx *ctx);
> > +static int nsim_dev_port_param_get(struct devlink_port *port, u32 id,
> > + struct devlink_param_gset_ctx *ctx);
> > +
> > static int
> > nsim_dev_take_snapshot(struct devlink *devlink,
> > const struct devlink_region_ops *ops,
> > @@ -339,6 +344,7 @@ static int nsim_dev_resources_register(struct devlink *devlink)
> > enum nsim_devlink_param_id {
> > NSIM_DEVLINK_PARAM_ID_BASE = DEVLINK_PARAM_GENERIC_ID_MAX,
> > NSIM_DEVLINK_PARAM_ID_TEST1,
> > + NSIM_DEVLINK_PARAM_ID_TEST2,
> > };
> > static const struct devlink_param nsim_devlink_params[] = {
> > @@ -349,6 +355,10 @@ static const struct devlink_param nsim_devlink_params[] = {
> > "test1", DEVLINK_PARAM_TYPE_BOOL,
> > BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
> > NULL, NULL, NULL),
> > + DEVLINK_PARAM_DRIVER(NSIM_DEVLINK_PARAM_ID_TEST2,
> > + "test1", DEVLINK_PARAM_TYPE_U32,
> > + BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
> > + NULL, NULL, NULL),
> > };
> > static void nsim_devlink_set_params_init_values(struct nsim_dev *nsim_dev,
> > @@ -892,6 +902,11 @@ nsim_dev_devlink_trap_policer_counter_get(struct devlink *devlink,
> > return 0;
> > }
> > +static const struct devlink_port_param_ops nsim_dev_port_param_ops = {
> > + .get = nsim_dev_port_param_get,
> > + .set = nsim_dev_port_param_set,
> > +};
> > +
> > static const struct devlink_ops nsim_dev_devlink_ops = {
> > .supported_flash_update_params = DEVLINK_SUPPORT_FLASH_UPDATE_COMPONENT |
> > DEVLINK_SUPPORT_FLASH_UPDATE_OVERWRITE_MASK,
> > @@ -905,6 +920,7 @@ static const struct devlink_ops nsim_dev_devlink_ops = {
> > .trap_group_set = nsim_dev_devlink_trap_group_set,
> > .trap_policer_set = nsim_dev_devlink_trap_policer_set,
> > .trap_policer_counter_get = nsim_dev_devlink_trap_policer_counter_get,
> > + .port_param_ops = &nsim_dev_port_param_ops,
> > };
> > #define NSIM_DEV_MAX_MACS_DEFAULT 32
> > @@ -1239,6 +1255,36 @@ int nsim_dev_port_del(struct nsim_bus_dev *nsim_bus_dev,
> > return err;
> > }
> > +static int nsim_dev_port_param_get(struct devlink_port *port, u32 id,
> > + struct devlink_param_gset_ctx *ctx)
> > +{
> > + struct nsim_dev *nsim_dev = devlink_priv(port->devlink);
> > + struct nsim_dev_port *nsim_port =
> > + __nsim_dev_port_lookup(nsim_dev, port->index);
> > +
> > + if (id == NSIM_DEVLINK_PARAM_ID_TEST2) {
> > + ctx->val.vu32 = nsim_port->test_parameter_value;
> > + return 0;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int nsim_dev_port_param_set(struct devlink_port *port, u32 id,
> > + struct devlink_param_gset_ctx *ctx)
> > +{
> > + struct nsim_dev *nsim_dev = devlink_priv(port->devlink);
> > + struct nsim_dev_port *nsim_port =
> > + __nsim_dev_port_lookup(nsim_dev, port->index);
> > +
> > + if (id == NSIM_DEVLINK_PARAM_ID_TEST2) {
> > + nsim_port->test_parameter_value = ctx->val.vu32;
> > + return 0;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > int nsim_dev_init(void)
> > {
> > nsim_dev_ddir = debugfs_create_dir(DRV_NAME, NULL);
> > diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
> > index 7ff24e03577b..4f5fc491c8d6 100644
> > --- a/drivers/net/netdevsim/netdevsim.h
> > +++ b/drivers/net/netdevsim/netdevsim.h
> > @@ -203,6 +203,7 @@ struct nsim_dev_port {
> > unsigned int port_index;
> > struct dentry *ddir;
> > struct netdevsim *ns;
> > + u32 test_parameter_value;
> > };
> > struct nsim_dev {
> > diff --git a/include/net/devlink.h b/include/net/devlink.h
> > index 853420db5d32..85a7b9970496 100644
> > --- a/include/net/devlink.h
> > +++ b/include/net/devlink.h
> > @@ -1189,6 +1189,16 @@ enum devlink_trap_group_generic_id {
> > .min_burst = _min_burst, \
> > }
> > +struct devlink_port_param_ops {
> > + int (*get)(struct devlink_port *port, u32 id,
> > + struct devlink_param_gset_ctx *ctx);
> > + int (*set)(struct devlink_port *port, u32 id,
> > + struct devlink_param_gset_ctx *ctx);
> > + int (*validate)(struct devlink_port *port, u32 id,
> > + union devlink_param_value val,
> > + struct netlink_ext_ack *extack);
> > +};
> > +
> > struct devlink_ops {
> > /**
> > * @supported_flash_update_params:
> > @@ -1451,6 +1461,7 @@ struct devlink_ops {
> > struct devlink_port *port,
> > enum devlink_port_fn_state state,
> > struct netlink_ext_ack *extack);
> > + struct devlink_port_param_ops *port_param_ops;
> > };
> > static inline void *devlink_priv(struct devlink *devlink)
> > diff --git a/net/core/devlink.c b/net/core/devlink.c
> > index 737b61c2976e..20f3545f4e7b 100644
> > --- a/net/core/devlink.c
> > +++ b/net/core/devlink.c
> > @@ -3918,6 +3918,7 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
> > enum devlink_command cmd,
> > u32 portid, u32 seq, int flags)
> > {
> > + struct devlink_port *dl_port;
> > union devlink_param_value param_value[DEVLINK_PARAM_CMODE_MAX + 1];
> > bool param_value_set[DEVLINK_PARAM_CMODE_MAX + 1] = {};
> > const struct devlink_param *param = param_item->param;
> > @@ -3941,7 +3942,20 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
> > if (!param_item->published)
> > continue;
> > ctx.cmode = i;
> > - err = devlink_param_get(devlink, param, &ctx);
> > + if ((cmd == DEVLINK_CMD_PORT_PARAM_GET ||
> > + cmd == DEVLINK_CMD_PORT_PARAM_NEW ||
> > + cmd == DEVLINK_CMD_PORT_PARAM_DEL) &&
> > + devlink->ops->port_param_ops) {
> > +
> > + dl_port = devlink_port_get_by_index(devlink,
> > + port_index);
> > + err = devlink->ops->port_param_ops->get(dl_port,
> > + param->id,
> > + &ctx);
> > + } else {
> > + err = devlink_param_get(devlink, param, &ctx);
> > + }
> > +
> > if (err)
> > return err;
> > param_value[i] = ctx.val;
>