Re: [PATCH RFC 05/20] ctlv: Prepare message input handling

[Jason Gunthorpe]

> [ ... 38 lines skipped ... ]
> --- /dev/null
> +++ b/drivers/ctlv/Kconfig
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +menuconfig CTLV
> +	tristate "CTLV character device TLV UAPI"
> +	help
> +	  CTLV provides character device UAPIs described by a checked-in YAML
> +	  specification. It owns the character device lifetime, the strict TLV
> +	  message format, request validation, reply serialization, the large
> +	  payloads a request describes rather than carries, per-open event
> +	  queues and runtime schema introspection, so families only implement
> +	  semantics.
> +
> +	  If you don't know what to do here, say N.

This should probably just be a simple selectable config instead of a
full blown menuconfig. ie one with no description. Since this is
really just a tool for subsystems to use every subsystem that uses it
should just select it.

So:

config CTLV
   bool


> [ ... 159 lines skipped ... ]
> +static bool ctlv_message_nest_index_ok(const struct ctlv_cursor *nest)
> +{
> +	const struct ctlv_message_input_index *index = nest->msg->index;
> +	const struct ctlv_message_input_nest *indexed;
> +	const struct ctlv_message_input_scope *scope;
> +	const struct ctlv_attr *attr;
> +
> +	if (WARN_ON_ONCE(!nest->msg->request || !index ||
> +			 nest->index_nest_scope >= index->scopes_count))
> +		return false;
> +	scope = &index->scopes[nest->index_nest_scope];
> +	if (WARN_ON_ONCE(scope->nest >= index->nests_count))
> +		return false;
> +	indexed = &index->nests[scope->nest];
> +	attr = (const void *)((const u8 *)nest->msg->root + indexed->offset);
> +	if (WARN_ON_ONCE(attr != nest->attr))
> +		return false;
> +	return !WARN_ON_ONCE(scope->tree != nest->tree || scope->node != nest->node);

Maybe wrap these invariant assertions in a helper and we can compile
them out?

  #ifdef CONFIG_CTLV_DEBUG
  #define CTLV_ASSERT(xxx) WARN_ON_ONCE(xxx)
  #endif

It helps manage expectations around WARN_ON. I assume these have all
been checked to guarentee they cannot be triggered by users space?

-- 
Jason