devlink: convert occ_get op to separate registration

This resolves race during initialization where the resources with
ops are registered before driver and the structures used by occ_get
op is initialized. So keep occ_get callbacks registered only when
all structs are initialized.

The example flows, as it is in mlxsw:
1) driver load/asic probe:
   mlxsw_core
      -> mlxsw_sp_resources_register
        -> mlxsw_sp_kvdl_resources_register
          -> devlink_resource_register IDX
   mlxsw_spectrum
      -> mlxsw_sp_kvdl_init
        -> mlxsw_sp_kvdl_parts_init
          -> mlxsw_sp_kvdl_part_init
            -> devlink_resource_size_get IDX (to get the current setup
                                              size from devlink)
        -> devlink_resource_occ_get_register IDX (register current
                                                  occupancy getter)
2) reload triggered by devlink command:
  -> mlxsw_devlink_core_bus_device_reload
    -> mlxsw_sp_fini
      -> mlxsw_sp_kvdl_fini
	-> devlink_resource_occ_get_unregister IDX
    (struct mlxsw_sp *mlxsw_sp is freed at this point, call to occ get
     which is using mlxsw_sp would cause use-after free)
    -> mlxsw_sp_init
      -> mlxsw_sp_kvdl_init
        -> mlxsw_sp_kvdl_parts_init
          -> mlxsw_sp_kvdl_part_init
            -> devlink_resource_size_get IDX (to get the current setup
                                              size from devlink)
        -> devlink_resource_occ_get_register IDX (register current
                                                  occupancy getter)

Fixes: d9f9b9a4d05f ("devlink: Add support for resource abstraction")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -3805,18 +3805,6 @@ static const struct mlxsw_config_profile mlxsw_sp_config_profile = {
 	},
 };
 
-static u64 mlxsw_sp_resource_kvd_linear_occ_get(struct devlink *devlink)
-{
-	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
-	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
-
-	return mlxsw_sp_kvdl_occ_get(mlxsw_sp);
-}
-
-static const struct devlink_resource_ops mlxsw_sp_resource_kvd_linear_ops = {
-	.occ_get = mlxsw_sp_resource_kvd_linear_occ_get,
-};
-
 static void
 mlxsw_sp_resource_size_params_prepare(struct mlxsw_core *mlxsw_core,
 				      struct devlink_resource_size_params *kvd_size_params,
@@ -3877,8 +3865,7 @@ static int mlxsw_sp_resources_register(struct mlxsw_core *mlxsw_core)
 	err = devlink_resource_register(devlink, MLXSW_SP_RESOURCE_NAME_KVD,
 					kvd_size, MLXSW_SP_RESOURCE_KVD,
 					DEVLINK_RESOURCE_ID_PARENT_TOP,
-					&kvd_size_params,
-					NULL);
+					&kvd_size_params);
 	if (err)
 		return err;
 
@@ -3887,8 +3874,7 @@ static int mlxsw_sp_resources_register(struct mlxsw_core *mlxsw_core)
 					linear_size,
 					MLXSW_SP_RESOURCE_KVD_LINEAR,
 					MLXSW_SP_RESOURCE_KVD,
-					&linear_size_params,
-					&mlxsw_sp_resource_kvd_linear_ops);
+					&linear_size_params);
 	if (err)
 		return err;
 
@@ -3905,8 +3891,7 @@ static int mlxsw_sp_resources_register(struct mlxsw_core *mlxsw_core)
 					double_size,
 					MLXSW_SP_RESOURCE_KVD_HASH_DOUBLE,
 					MLXSW_SP_RESOURCE_KVD,
-					&hash_double_size_params,
-					NULL);
+					&hash_double_size_params);
 	if (err)
 		return err;
 
@@ -3915,8 +3900,7 @@ static int mlxsw_sp_resources_register(struct mlxsw_core *mlxsw_core)
 					single_size,
 					MLXSW_SP_RESOURCE_KVD_HASH_SINGLE,
 					MLXSW_SP_RESOURCE_KVD,
-					&hash_single_size_params,
-					NULL);
+					&hash_single_size_params);
 	if (err)
 		return err;
 

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -442,7 +442,6 @@ void mlxsw_sp_kvdl_free(struct mlxsw_sp *mlxsw_sp, int entry_index);
 int mlxsw_sp_kvdl_alloc_size_query(struct mlxsw_sp *mlxsw_sp,
 				   unsigned int entry_count,
 				   unsigned int *p_alloc_size);
-u64 mlxsw_sp_kvdl_occ_get(const struct mlxsw_sp *mlxsw_sp);
 int mlxsw_sp_kvdl_resources_register(struct mlxsw_core *mlxsw_core);
 
 struct mlxsw_sp_acl_rule_info {

drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c

@@ -315,8 +315,9 @@ static u64 mlxsw_sp_kvdl_part_occ(struct mlxsw_sp_kvdl_part *part)
 	return occ;
 }
 
-u64 mlxsw_sp_kvdl_occ_get(const struct mlxsw_sp *mlxsw_sp)
+static u64 mlxsw_sp_kvdl_occ_get(void *priv)
 {
+	const struct mlxsw_sp *mlxsw_sp = priv;
 	u64 occ = 0;
 	int i;
 
@@ -326,48 +327,33 @@ u64 mlxsw_sp_kvdl_occ_get(const struct mlxsw_sp *mlxsw_sp)
 	return occ;
 }
 
-static u64 mlxsw_sp_kvdl_single_occ_get(struct devlink *devlink)
+static u64 mlxsw_sp_kvdl_single_occ_get(void *priv)
 {
-	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
-	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	const struct mlxsw_sp *mlxsw_sp = priv;
 	struct mlxsw_sp_kvdl_part *part;
 
 	part = mlxsw_sp->kvdl->parts[MLXSW_SP_KVDL_PART_ID_SINGLE];
 	return mlxsw_sp_kvdl_part_occ(part);
 }
 
-static u64 mlxsw_sp_kvdl_chunks_occ_get(struct devlink *devlink)
+static u64 mlxsw_sp_kvdl_chunks_occ_get(void *priv)
 {
-	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
-	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	const struct mlxsw_sp *mlxsw_sp = priv;
 	struct mlxsw_sp_kvdl_part *part;
 
 	part = mlxsw_sp->kvdl->parts[MLXSW_SP_KVDL_PART_ID_CHUNKS];
 	return mlxsw_sp_kvdl_part_occ(part);
 }
 
-static u64 mlxsw_sp_kvdl_large_chunks_occ_get(struct devlink *devlink)
+static u64 mlxsw_sp_kvdl_large_chunks_occ_get(void *priv)
 {
-	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
-	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	const struct mlxsw_sp *mlxsw_sp = priv;
 	struct mlxsw_sp_kvdl_part *part;
 
 	part = mlxsw_sp->kvdl->parts[MLXSW_SP_KVDL_PART_ID_LARGE_CHUNKS];
 	return mlxsw_sp_kvdl_part_occ(part);
 }
 
-static const struct devlink_resource_ops mlxsw_sp_kvdl_single_ops = {
-	.occ_get = mlxsw_sp_kvdl_single_occ_get,
-};
-
-static const struct devlink_resource_ops mlxsw_sp_kvdl_chunks_ops = {
-	.occ_get = mlxsw_sp_kvdl_chunks_occ_get,
-};
-
-static const struct devlink_resource_ops mlxsw_sp_kvdl_chunks_large_ops = {
-	.occ_get = mlxsw_sp_kvdl_large_chunks_occ_get,
-};
-
 int mlxsw_sp_kvdl_resources_register(struct mlxsw_core *mlxsw_core)
 {
 	struct devlink *devlink = priv_to_devlink(mlxsw_core);
@@ -386,8 +372,7 @@ int mlxsw_sp_kvdl_resources_register(struct mlxsw_core *mlxsw_core)
 					MLXSW_SP_KVDL_SINGLE_SIZE,
 					MLXSW_SP_RESOURCE_KVD_LINEAR_SINGLE,
 					MLXSW_SP_RESOURCE_KVD_LINEAR,
-					&size_params,
-					&mlxsw_sp_kvdl_single_ops);
+					&size_params);
 	if (err)
 		return err;
 
@@ -398,8 +383,7 @@ int mlxsw_sp_kvdl_resources_register(struct mlxsw_core *mlxsw_core)
 					MLXSW_SP_KVDL_CHUNKS_SIZE,
 					MLXSW_SP_RESOURCE_KVD_LINEAR_CHUNKS,
 					MLXSW_SP_RESOURCE_KVD_LINEAR,
-					&size_params,
-					&mlxsw_sp_kvdl_chunks_ops);
+					&size_params);
 	if (err)
 		return err;
 
@@ -410,13 +394,13 @@ int mlxsw_sp_kvdl_resources_register(struct mlxsw_core *mlxsw_core)
 					MLXSW_SP_KVDL_LARGE_CHUNKS_SIZE,
 					MLXSW_SP_RESOURCE_KVD_LINEAR_LARGE_CHUNKS,
 					MLXSW_SP_RESOURCE_KVD_LINEAR,
-					&size_params,
-					&mlxsw_sp_kvdl_chunks_large_ops);
+					&size_params);
 	return err;
 }
 
 int mlxsw_sp_kvdl_init(struct mlxsw_sp *mlxsw_sp)
 {
+	struct devlink *devlink = priv_to_devlink(mlxsw_sp->core);
 	struct mlxsw_sp_kvdl *kvdl;
 	int err;
 
@@ -429,6 +413,23 @@ int mlxsw_sp_kvdl_init(struct mlxsw_sp *mlxsw_sp)
 	if (err)
 		goto err_kvdl_parts_init;
 
+	devlink_resource_occ_get_register(devlink,
+					  MLXSW_SP_RESOURCE_KVD_LINEAR,
+					  mlxsw_sp_kvdl_occ_get,
+					  mlxsw_sp);
+	devlink_resource_occ_get_register(devlink,
+					  MLXSW_SP_RESOURCE_KVD_LINEAR_SINGLE,
+					  mlxsw_sp_kvdl_single_occ_get,
+					  mlxsw_sp);
+	devlink_resource_occ_get_register(devlink,
+					  MLXSW_SP_RESOURCE_KVD_LINEAR_CHUNKS,
+					  mlxsw_sp_kvdl_chunks_occ_get,
+					  mlxsw_sp);
+	devlink_resource_occ_get_register(devlink,
+					  MLXSW_SP_RESOURCE_KVD_LINEAR_LARGE_CHUNKS,
+					  mlxsw_sp_kvdl_large_chunks_occ_get,
+					  mlxsw_sp);
+
 	return 0;
 
 err_kvdl_parts_init:
@@ -438,6 +439,16 @@ err_kvdl_parts_init:
 
 void mlxsw_sp_kvdl_fini(struct mlxsw_sp *mlxsw_sp)
 {
+	struct devlink *devlink = priv_to_devlink(mlxsw_sp->core);
+
+	devlink_resource_occ_get_unregister(devlink,
+					    MLXSW_SP_RESOURCE_KVD_LINEAR_LARGE_CHUNKS);
+	devlink_resource_occ_get_unregister(devlink,
+					    MLXSW_SP_RESOURCE_KVD_LINEAR_CHUNKS);
+	devlink_resource_occ_get_unregister(devlink,
+					    MLXSW_SP_RESOURCE_KVD_LINEAR_SINGLE);
+	devlink_resource_occ_get_unregister(devlink,
+					    MLXSW_SP_RESOURCE_KVD_LINEAR);
 	mlxsw_sp_kvdl_parts_fini(mlxsw_sp);
 	kfree(mlxsw_sp->kvdl);
 }

drivers/net/netdevsim/devlink.c

@@ -30,52 +30,36 @@ static struct net *nsim_devlink_net(struct devlink *devlink)
 
 /* IPv4
  */
-static u64 nsim_ipv4_fib_resource_occ_get(struct devlink *devlink)
+static u64 nsim_ipv4_fib_resource_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB, false);
 }
 
-static struct devlink_resource_ops nsim_ipv4_fib_res_ops = {
-	.occ_get = nsim_ipv4_fib_resource_occ_get,
-};
-
-static u64 nsim_ipv4_fib_rules_res_occ_get(struct devlink *devlink)
+static u64 nsim_ipv4_fib_rules_res_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB_RULES, false);
 }
 
-static struct devlink_resource_ops nsim_ipv4_fib_rules_res_ops = {
-	.occ_get = nsim_ipv4_fib_rules_res_occ_get,
-};
-
 /* IPv6
  */
-static u64 nsim_ipv6_fib_resource_occ_get(struct devlink *devlink)
+static u64 nsim_ipv6_fib_resource_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB, false);
 }
 
-static struct devlink_resource_ops nsim_ipv6_fib_res_ops = {
-	.occ_get = nsim_ipv6_fib_resource_occ_get,
-};
-
-static u64 nsim_ipv6_fib_rules_res_occ_get(struct devlink *devlink)
+static u64 nsim_ipv6_fib_rules_res_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB_RULES, false);
 }
 
-static struct devlink_resource_ops nsim_ipv6_fib_rules_res_ops = {
-	.occ_get = nsim_ipv6_fib_rules_res_occ_get,
-};
-
 static int devlink_resources_register(struct devlink *devlink)
 {
 	struct devlink_resource_size_params params = {
@@ -91,7 +75,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	err = devlink_resource_register(devlink, "IPv4", (u64)-1,
 					NSIM_RESOURCE_IPV4,
 					DEVLINK_RESOURCE_ID_PARENT_TOP,
-					&params, NULL);
+					&params);
 	if (err) {
 		pr_err("Failed to register IPv4 top resource\n");
 		goto out;
@@ -100,8 +84,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB, true);
 	err = devlink_resource_register(devlink, "fib", n,
 					NSIM_RESOURCE_IPV4_FIB,
-					NSIM_RESOURCE_IPV4,
-					&params, &nsim_ipv4_fib_res_ops);
+					NSIM_RESOURCE_IPV4, &params);
 	if (err) {
 		pr_err("Failed to register IPv4 FIB resource\n");
 		return err;
@@ -110,8 +93,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB_RULES, true);
 	err = devlink_resource_register(devlink, "fib-rules", n,
 					NSIM_RESOURCE_IPV4_FIB_RULES,
-					NSIM_RESOURCE_IPV4,
-					&params, &nsim_ipv4_fib_rules_res_ops);
+					NSIM_RESOURCE_IPV4, &params);
 	if (err) {
 		pr_err("Failed to register IPv4 FIB rules resource\n");
 		return err;
@@ -121,7 +103,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	err = devlink_resource_register(devlink, "IPv6", (u64)-1,
 					NSIM_RESOURCE_IPV6,
 					DEVLINK_RESOURCE_ID_PARENT_TOP,
-					&params, NULL);
+					&params);
 	if (err) {
 		pr_err("Failed to register IPv6 top resource\n");
 		goto out;
@@ -130,8 +112,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB, true);
 	err = devlink_resource_register(devlink, "fib", n,
 					NSIM_RESOURCE_IPV6_FIB,
-					NSIM_RESOURCE_IPV6,
-					&params, &nsim_ipv6_fib_res_ops);
+					NSIM_RESOURCE_IPV6, &params);
 	if (err) {
 		pr_err("Failed to register IPv6 FIB resource\n");
 		return err;
@@ -140,12 +121,28 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB_RULES, true);
 	err = devlink_resource_register(devlink, "fib-rules", n,
 					NSIM_RESOURCE_IPV6_FIB_RULES,
-					NSIM_RESOURCE_IPV6,
-					&params, &nsim_ipv6_fib_rules_res_ops);
+					NSIM_RESOURCE_IPV6, &params);
 	if (err) {
 		pr_err("Failed to register IPv6 FIB rules resource\n");
 		return err;
 	}
+
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV4_FIB,
+					  nsim_ipv4_fib_resource_occ_get,
+					  net);
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV4_FIB_RULES,
+					  nsim_ipv4_fib_rules_res_occ_get,
+					  net);
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV6_FIB,
+					  nsim_ipv6_fib_resource_occ_get,
+					  net);
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV6_FIB_RULES,
+					  nsim_ipv6_fib_rules_res_occ_get,
+					  net);
 out:
 	return err;
 }

include/net/devlink.h

@@ -231,14 +231,6 @@ struct devlink_dpipe_headers {
 	unsigned int headers_count;
 };
 
-/**
- * struct devlink_resource_ops - resource ops
- * @occ_get: get the occupied size
- */
-struct devlink_resource_ops {
-	u64 (*occ_get)(struct devlink *devlink);
-};
-
 /**
  * struct devlink_resource_size_params - resource's size parameters
  * @size_min: minimum size which can be set
@@ -265,6 +257,8 @@ devlink_resource_size_params_init(struct devlink_resource_size_params *size_para
 	size_params->unit = unit;
 }
 
+typedef u64 devlink_resource_occ_get_t(void *priv);
+
 /**
  * struct devlink_resource - devlink resource
  * @name: name of the resource
@@ -277,7 +271,6 @@ devlink_resource_size_params_init(struct devlink_resource_size_params *size_para
  * @size_params: size parameters
  * @list: parent list
  * @resource_list: list of child resources
- * @resource_ops: resource ops
  */
 struct devlink_resource {
 	const char *name;
@@ -289,7 +282,8 @@ struct devlink_resource {
 	struct devlink_resource_size_params size_params;
 	struct list_head list;
 	struct list_head resource_list;
-	const struct devlink_resource_ops *resource_ops;
+	devlink_resource_occ_get_t *occ_get;
+	void *occ_get_priv;
 };
 
 #define DEVLINK_RESOURCE_ID_PARENT_TOP 0
@@ -409,8 +403,7 @@ int devlink_resource_register(struct devlink *devlink,
 			      u64 resource_size,
 			      u64 resource_id,
 			      u64 parent_resource_id,
-			      const struct devlink_resource_size_params *size_params,
-			      const struct devlink_resource_ops *resource_ops);
+			      const struct devlink_resource_size_params *size_params);
 void devlink_resources_unregister(struct devlink *devlink,
 				  struct devlink_resource *resource);
 int devlink_resource_size_get(struct devlink *devlink,
@@ -419,6 +412,12 @@ int devlink_resource_size_get(struct devlink *devlink,
 int devlink_dpipe_table_resource_set(struct devlink *devlink,
 				     const char *table_name, u64 resource_id,
 				     u64 resource_units);
+void devlink_resource_occ_get_register(struct devlink *devlink,
+				       u64 resource_id,
+				       devlink_resource_occ_get_t *occ_get,
+				       void *occ_get_priv);
+void devlink_resource_occ_get_unregister(struct devlink *devlink,
+					 u64 resource_id);
 
 #else
 
@@ -562,8 +561,7 @@ devlink_resource_register(struct devlink *devlink,
 			  u64 resource_size,
 			  u64 resource_id,
 			  u64 parent_resource_id,
-			  const struct devlink_resource_size_params *size_params,
-			  const struct devlink_resource_ops *resource_ops)
+			  const struct devlink_resource_size_params *size_params)
 {
 	return 0;
 }
@@ -589,6 +587,20 @@ devlink_dpipe_table_resource_set(struct devlink *devlink,
 	return -EOPNOTSUPP;
 }
 
+static inline void
+devlink_resource_occ_get_register(struct devlink *devlink,
+				  u64 resource_id,
+				  devlink_resource_occ_get_t *occ_get,
+				  void *occ_get_priv)
+{
+}
+
+static inline void
+devlink_resource_occ_get_unregister(struct devlink *devlink,
+				    u64 resource_id)
+{
+}
+
 #endif
 
 #endif /* _NET_DEVLINK_H_ */

net/core/devlink.c

@@ -2405,6 +2405,16 @@ devlink_resource_size_params_put(struct devlink_resource *resource,
 	return 0;
 }
 
+static int devlink_resource_occ_put(struct devlink_resource *resource,
+				    struct sk_buff *skb)
+{
+	if (!resource->occ_get)
+		return 0;
+	return nla_put_u64_64bit(skb, DEVLINK_ATTR_RESOURCE_OCC,
+				 resource->occ_get(resource->occ_get_priv),
+				 DEVLINK_ATTR_PAD);
+}
+
 static int devlink_resource_put(struct devlink *devlink, struct sk_buff *skb,
 				struct devlink_resource *resource)
 {
@@ -2425,11 +2435,8 @@ static int devlink_resource_put(struct devlink *devlink, struct sk_buff *skb,
 	if (resource->size != resource->size_new)
 		nla_put_u64_64bit(skb, DEVLINK_ATTR_RESOURCE_SIZE_NEW,
 				  resource->size_new, DEVLINK_ATTR_PAD);
-	if (resource->resource_ops && resource->resource_ops->occ_get)
-		if (nla_put_u64_64bit(skb, DEVLINK_ATTR_RESOURCE_OCC,
-				      resource->resource_ops->occ_get(devlink),
-				      DEVLINK_ATTR_PAD))
-			goto nla_put_failure;
+	if (devlink_resource_occ_put(resource, skb))
+		goto nla_put_failure;
 	if (devlink_resource_size_params_put(resource, skb))
 		goto nla_put_failure;
 	if (list_empty(&resource->resource_list))
@@ -3162,15 +3169,13 @@ EXPORT_SYMBOL_GPL(devlink_dpipe_table_unregister);
  *	@resource_id: resource's id
  *	@parent_reosurce_id: resource's parent id
  *	@size params: size parameters
- *	@resource_ops: resource ops
  */
 int devlink_resource_register(struct devlink *devlink,
 			      const char *resource_name,
 			      u64 resource_size,
 			      u64 resource_id,
 			      u64 parent_resource_id,
-			      const struct devlink_resource_size_params *size_params,
-			      const struct devlink_resource_ops *resource_ops)
+			      const struct devlink_resource_size_params *size_params)
 {
 	struct devlink_resource *resource;
 	struct list_head *resource_list;
@@ -3213,7 +3218,6 @@ int devlink_resource_register(struct devlink *devlink,
 	resource->size = resource_size;
 	resource->size_new = resource_size;
 	resource->id = resource_id;
-	resource->resource_ops = resource_ops;
 	resource->size_valid = true;
 	memcpy(&resource->size_params, size_params,
 	       sizeof(resource->size_params));
@@ -3315,6 +3319,58 @@ out:
 }
 EXPORT_SYMBOL_GPL(devlink_dpipe_table_resource_set);
 
+/**
+ *	devlink_resource_occ_get_register - register occupancy getter
+ *
+ *	@devlink: devlink
+ *	@resource_id: resource id
+ *	@occ_get: occupancy getter callback
+ *	@occ_get_priv: occupancy getter callback priv
+ */
+void devlink_resource_occ_get_register(struct devlink *devlink,
+				       u64 resource_id,
+				       devlink_resource_occ_get_t *occ_get,
+				       void *occ_get_priv)
+{
+	struct devlink_resource *resource;
+
+	mutex_lock(&devlink->lock);
+	resource = devlink_resource_find(devlink, NULL, resource_id);
+	if (WARN_ON(!resource))
+		goto out;
+	WARN_ON(resource->occ_get);
+
+	resource->occ_get = occ_get;
+	resource->occ_get_priv = occ_get_priv;
+out:
+	mutex_unlock(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devlink_resource_occ_get_register);
+
+/**
+ *	devlink_resource_occ_get_unregister - unregister occupancy getter
+ *
+ *	@devlink: devlink
+ *	@resource_id: resource id
+ */
+void devlink_resource_occ_get_unregister(struct devlink *devlink,
+					 u64 resource_id)
+{
+	struct devlink_resource *resource;
+
+	mutex_lock(&devlink->lock);
+	resource = devlink_resource_find(devlink, NULL, resource_id);
+	if (WARN_ON(!resource))
+		goto out;
+	WARN_ON(!resource->occ_get);
+
+	resource->occ_get = NULL;
+	resource->occ_get_priv = NULL;
+out:
+	mutex_unlock(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devlink_resource_occ_get_unregister);
+
 static int __init devlink_module_init(void)
 {
 	return genl_register_family(&devlink_nl_family);