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>

1 files changed, 39 insertions, 28 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
index 8796db44dcc3..fe4327f547d2 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
+++ b/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);
 }