From: Greg KH <gregkh@linuxfoundation.org>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: linux-usb@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH] usb: renesas_usbhs: Use struct assignment instead of memcpy()
Date: Tue, 18 Jun 2019 07:59:15 +0200 [thread overview]
Message-ID: <20190618055915.GA5904@kroah.com> (raw)
In-Reply-To: <1560424728-13929-1-git-send-email-yoshihiro.shimoda.uh@renesas.com>
On Thu, Jun 13, 2019 at 08:18:48PM +0900, Yoshihiro Shimoda wrote:
> To avoid the error-proneness of calls to sizeof() in the memcpy,
> this patch uses struct assignment instead of memcpy.
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
> This patch is based on Greg's linux-usb.git / usb-next branch.
> Note that mod_host.c also has memcpy but we cannot use struct assignment
> for it because the type of urb->setup_patcket is just "unsigned char *".
>
> drivers/usb/renesas_usbhs/common.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
> index a501ea6..ebbe322 100644
> --- a/drivers/usb/renesas_usbhs/common.c
> +++ b/drivers/usb/renesas_usbhs/common.c
> @@ -651,9 +651,8 @@ static struct renesas_usbhs_platform_info *usbhs_parse_dt(struct device *dev)
> return NULL;
>
> dparam = &info->driver_param;
> - memcpy(dparam, &data->param, sizeof(data->param));
> - memcpy(&info->platform_callback, data->platform_callback,
> - sizeof(*data->platform_callback));
> + *dparam = data->param;
> + info->platform_callback = *data->platform_callback;
How are the original calls here "error-prone"? Yes, the compiler will
end up calling memcpy somehow with this change, but it feels "wrong" to
hide a memory copy like this.
So are you _sure_ you want this change?
thanks,
greg k-h
next prev parent reply other threads:[~2019-06-18 7:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 11:18 [PATCH] usb: renesas_usbhs: Use struct assignment instead of memcpy() Yoshihiro Shimoda
2019-06-17 8:40 ` Simon Horman
2019-06-18 5:59 ` Greg KH [this message]
2019-06-18 7:26 ` Geert Uytterhoeven
2019-06-18 8:42 ` Yoshihiro Shimoda
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