linux-kernel - Re: [patch 3/4] skd: use strncpy() as a cleanup

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Date:	Fri, 13 Sep 2013 14:03:23 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Dan Carpenter <dan.carpenter@...cle.com>
Cc:	Jens Axboe <axboe@...nel.dk>, Jeff Moyer <jmoyer@...hat.com>,
	Ramprasad Chinthekindi <rchinthekindi@...c-inc.com>,
	Akhil Bhansali <abhansali@...c-inc.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: Re: [patch 3/4] skd: use strncpy() as a cleanup

On Fri, Sep 13, 2013 at 10:05 AM, Dan Carpenter
<dan.carpenter@...cle.com> wrote:
> The code here is copying the version to inq.driver_version but we don't
> want it to be NUL terminated.  Instead we pad the rest of the array with
> spaces.  It's fewer lines to use strncpy() and maybe a little nicer.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
>
> diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
> index f892d95..20ad843 100644
> --- a/drivers/block/skd_main.c
> +++ b/drivers/block/skd_main.c
> @@ -2899,9 +2899,7 @@ static void skd_do_inq_page_da(struct skd_device *skdev,
>                                volatile struct fit_comp_error_info *skerr,
>                                uint8_t *cdb, uint8_t *buf)
>  {
> -       unsigned ver_byte;
>         unsigned max_bytes;
> -       char *ver = DRV_VER_COMPL;
>         struct driver_inquiry_data inq;
>         u16 val;
>
> @@ -2945,12 +2943,8 @@ static void skd_do_inq_page_da(struct skd_device *skdev,
>         /* Driver version, fixed lenth, padded with spaces on the right */
>         inq.driver_version_length = sizeof(inq.driver_version);
>         memset(&inq.driver_version, ' ', sizeof(inq.driver_version));
> -       for (ver_byte = 0; ver_byte < sizeof(inq.driver_version); ver_byte++) {
> -               if (ver[ver_byte] != 0)
> -                       inq.driver_version[ver_byte] = ver[ver_byte];
> -               else
> -                       break;
> -       }
> +       strncpy(inq.driver_version, DRV_VER_COMPL,
> +               min(sizeof(inq.driver_version), strlen(DRV_VER_COMPL)));

This does the exact same thing as memcpy(), right? So why not use that?
memcpy() has much simpler semantics than strncpy().

>         inq.page_length = cpu_to_be16((sizeof(inq) - 4));

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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