[PATCH 10/10] staging: unisys: visorbus: Clarify reason for device pointer checks

[Greg KH]

On Wed, Feb 01, 2017 at 05:39:02PM -0500, David Kershner wrote:
> From: David Binder <david.binder at unisys.com>
> 
> Clarifies why the pointers returned from visorbus_get_device_by_id() in
> visorbus are validated. The check is performed in order to be extra
> careful, for the sake of added security, that the s-Par backend is
> providing us with a valid device.
> 
> Signed-off-by: David Binder <david.binder at unisys.com>
> Signed-off-by: David Kershner <david.kershner at unisys.com>
> ---
>  drivers/staging/unisys/visorbus/visorchipset.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/staging/unisys/visorbus/visorchipset.c b/drivers/staging/unisys/visorbus/visorchipset.c
> index 188e224..07f8d05 100644
> --- a/drivers/staging/unisys/visorbus/visorchipset.c
> +++ b/drivers/staging/unisys/visorbus/visorchipset.c
> @@ -897,6 +897,7 @@ my_device_changestate(struct controlvm_message *inmsg)
>  	int err;
>  
>  	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
> +	/* Validate that s-Par backend gave a good device */

Same comment here as the previous review, this comment really isn't
needed, right?

>  	if (!dev_info) {
>  		POSTCODE_LINUX(DEVICE_CHANGESTATE_FAILURE_PC, dev_no, bus_no,
>  			       DIAG_SEVERITY_ERR);
> @@ -957,6 +958,7 @@ my_device_destroy(struct controlvm_message *inmsg)
>  	int err;
>  
>  	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
> +	/* Validate that s-Par backend gave a good device */

Or here.

thanks,

greg k-h