RE: [PATCH] usb: renesas_usbhs: Use struct assignment instead of memcpy()

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hi Greg,

> From: Greg KH, Sent: Tuesday, June 18, 2019 2:59 PM
> 
> 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"?

When I was developing the patch above [1], I had actually confused
about these arguments of memcpy...

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/drivers/usb/renesas_usbhs?h=usb-next&id=be21a02a5a5ec88b12ce535ead715d4bbb173a55

I think this is because object and pointer members are mixed in these structures.
So, as I mentioned on the following email [2], I should try to simplify the code
instead of this patch.

[2]
https://marc.info/?l=linux-usb&m=155748940717665&w=2

> So are you _sure_ you want this change?

I'm sorry, I would like to drop this patch.

Best regards,
Yoshihiro Shimoda

> thanks,
> 
> greg k-h