Re: [Xen-devel] [PATCH] xen-blkfront: prefer xenbus_scanf() over xenbus_gather()

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

On Thu, Jul 07, 2016 at 02:05:46AM -0600, Jan Beulich wrote:
> ... for single items being collected: It is more typesafe (as the
> compiler can check format string and to-be-written-to variable match)
> and requires one less parameter to be passed.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

> ---
>  drivers/block/xen-blkfront.c |   43 
> +++++++++++++++++++------------------------
>  1 file changed, 19 insertions(+), 24 deletions(-)
> 
> --- 4.7-rc6-prefer-xenbus_scanf.orig/drivers/block/xen-blkfront.c
> +++ 4.7-rc6-prefer-xenbus_scanf/drivers/block/xen-blkfront.c
> @@ -2208,10 +2208,9 @@ static void blkfront_setup_discard(struc
>               info->discard_granularity = discard_granularity;
>               info->discard_alignment = discard_alignment;
>       }
> -     err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
> -                 "discard-secure", "%d", &discard_secure,
> -                 NULL);
> -     if (!err)
> +     err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> +                        "discard-secure", "%u", &discard_secure);
> +     if (err > 0)

I would prefer an explicit err == 1 check (here and elsewhere), but I'm not 
going to block this patch because of that.

Roger.

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