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

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.samudr...@intel.com>

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.ma...@plvision.eu>
---
  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;

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