Hi Inaky,

> +
> +/*
> + * Destroy/release the contents of a 'struct tx_queue_entry'
> + *
> + * This releases resources allocated *inside* @entry and @entry
> + * itself.
> + */
> +static void tx_queue_entry_destroy_free(gpointer _entry, gpointer unused)

Can't this be simply tx_queue_entry_free?  And feel free to take struct
tx_queue_entry * here.  Casting the destructor in g_foo_foreach is
acceptable.

> +{
> +	struct tx_queue_entry *entry = _entry;
> +
> +	if (entry->destroy)
> +		entry->destroy(entry->data);

An empty line after if/while/for blocks please.  I will update the
coding-style document with this rule shortly.

> +	g_free(entry->pdus);
> +	g_free(entry);
> +}
> +

Regards,
-Denis