[PATCH] staging: greybus: add host device function pointer checks

[Bryan O'Donoghue]

On 20/12/16 20:49, Jason Hrycay wrote:
> Add sanity checks for cport_quiesce and cport_clear before invoking the
> callbacks as these function pointers are not required during the host
> device registration. This follows the logic implemented elsewhere for
> various other function pointers.
> 
> Signed-off-by: Jason Hrycay <jhrycay at gmail.com>
> ---
>  drivers/staging/greybus/connection.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/staging/greybus/connection.c b/drivers/staging/greybus/connection.c
> index 833f83b..aa040b1 100644
> --- a/drivers/staging/greybus/connection.c
> +++ b/drivers/staging/greybus/connection.c
> @@ -358,6 +358,9 @@ static int gb_connection_hd_cport_quiesce(struct gb_connection *connection)
>  	size_t peer_space;
>  	int ret;
>  
> +	if (!hd->driver->cport_quiesce)
> +		return 0;
> +
>  	peer_space = sizeof(struct gb_operation_msg_hdr) +
>  			sizeof(struct gb_cport_shutdown_request);
>  
> @@ -381,6 +384,9 @@ static int gb_connection_hd_cport_clear(struct gb_connection *connection)
>  	struct gb_host_device *hd = connection->hd;
>  	int ret;
>  
> +	if (!hd->driver->cport_clear)
> +		return 0;
> +
>  	ret = hd->driver->cport_clear(hd, connection->hd_cport_id);
>  	if (ret) {
>  		dev_err(&hd->dev, "%s: failed to clear host cport: %d\n",
> 

Looks obviously correct to me i.e. it's never a bad idea to sanity check
a function pointer before dereferencing it.

Reviewed-by: Bryan O'Donoghue <pure.logic at nexus-software.ie>