Re: [PATCH v1 4/5] IB/uverbs: ex_query_device: no need to clear the whole structure

[Haggai Eran <haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

On 29/01/2015 20:00, Yann Droneaud wrote:
> As only the requested fields are set and copied to userspace,
> there's no need to clear the content of the response structure
> beforehand.

Care must be taken to zero out all the data that is copied to userspace,
but I agree it can be done only to the parts that are unsupported as
this patch does.

Reviewed-by: Haggai Eran <haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

> Link: http://mid.gmane.org/cover.1422553023.git.ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org
> Cc: Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Cc: Shachar Raindel <raindel-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Cc: Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Cc: Haggai Eran <haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/infiniband/core/uverbs_cmd.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
> index 81d8b5aa2eb6..9520880a163f 100644
> --- a/drivers/infiniband/core/uverbs_cmd.c
> +++ b/drivers/infiniband/core/uverbs_cmd.c
> @@ -3328,9 +3328,9 @@ int ib_uverbs_ex_query_device(struct ib_uverbs_file *file,
>  	if (err)
>  		return err;
>  
> -	memset(&resp, 0, sizeof(resp));
>  	copy_query_dev_fields(file, &resp.base, &attr);
>  	resp.comp_mask = 0;
> +	resp.reserved = 0;
>  
>  	if (ucore->outlen < resp_len + sizeof(resp.odp_caps))
>  		goto end;
> @@ -3343,6 +3343,9 @@ int ib_uverbs_ex_query_device(struct ib_uverbs_file *file,
>  		attr.odp_caps.per_transport_caps.uc_odp_caps;
>  	resp.odp_caps.per_transport_caps.ud_odp_caps =
>  		attr.odp_caps.per_transport_caps.ud_odp_caps;
> +	resp.odp_caps.reserved = 0;
> +#else
> +	memset(&resp.odp_caps, 0, sizeof(resp.odp_caps));
>  #endif
>  	resp.comp_mask |= IB_USER_VERBS_EX_QUERY_DEVICE_ODP;
>  	resp_len += sizeof(resp.odp_caps);
>