Re: [Qemu-devel] [PATCH 04/42] tpm: lookup tpm backend class in tpm_driver_find_by_type()

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 10/09/2017 06:55 PM, Marc-André Lureau wrote:
> One step towards removing TPMDriverOps and driver registration.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>


> ---
>   tpm.c | 29 +++++++++++++++++++++--------
>   1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/tpm.c b/tpm.c
> index bc7d7470a8..04de8da5fd 100644
> --- a/tpm.c
> +++ b/tpm.c
> @@ -47,6 +47,24 @@ void tpm_register_driver(const TPMDriverOps *tdo)
>       be_drivers[tdo->type] = tdo;
>   }
>
> +static const TPMDriverOps *
> +tpm_driver_find_by_type(enum TpmType type)
> +{
> +    ObjectClass *oc;
> +    TPMBackendClass *bc;
> +    char *typename = g_strdup_printf("tpm-%s", TpmType_str(type));
> +
> +    oc = object_class_by_name(typename);
> +    g_free(typename);
> +
> +    if (!object_class_dynamic_cast(oc, TYPE_TPM_BACKEND)) {
> +        return NULL;
> +    }
> +
> +    bc = TPM_BACKEND_CLASS(oc);
> +    return bc->ops;
> +}
> +
>   /*
>    * Walk the list of available TPM backend drivers and display them on the
>    * screen.
> @@ -58,11 +76,11 @@ static void tpm_display_backend_drivers(void)
>       fprintf(stderr, "Supported TPM types (choose only one):\n");
>
>       for (i = 0; i < TPM_TYPE__MAX; i++) {
> -        if (be_drivers[i] == NULL) {
> +        const TPMDriverOps *ops = tpm_driver_find_by_type(i);
> +        if (!ops) {
>               continue;
>           }
> -        fprintf(stderr, "%12s   %s\n",
> -                TpmType_str(i), be_drivers[i]->desc);
> +        fprintf(stderr, "%12s   %s\n", TpmType_str(i), ops->desc);
>       }
>       fprintf(stderr, "\n");
>   }
> @@ -196,11 +214,6 @@ int tpm_config_parse(QemuOptsList *opts_list, const char *optarg)
>
>   #endif /* CONFIG_TPM */
>
> -static const TPMDriverOps *tpm_driver_find_by_type(enum TpmType type)
> -{
> -    return be_drivers[type];
> -}
> -
>   /*
>    * Walk the list of active TPM backends and collect information about them
>    * following the schema description in qapi-schema.json.