On Sun, Mar 07, 2021 at 09:14:26AM +0800, Zhangkun wrote:
> On 3/7/21 12:25 AM, Greg Kroah-Hartman wrote:
> > On Sat, Mar 06, 2021 at 08:06:44PM +0800, zhangkun4jr@xxxxxxx wrote:
> >> From: Zhang Kun <zhangkun@xxxxxxxxxx>
> >>
> >> The value assigned to len by sg_pcopy_from_buffer() never used for
> >> anything, so remove it.
> >>
> >> Signed-off-by: Zhang Kun <zhangkun@xxxxxxxxxx>
> >> ---
> >> drivers/usb/host/xhci.c | 3 +--
> >> 1 file changed, 1 insertion(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> >> index bd27bd670104..6ebda89d476c 100644
> >> --- a/drivers/usb/host/xhci.c
> >> +++ b/drivers/usb/host/xhci.c
> >> @@ -1335,7 +1335,6 @@ static bool xhci_urb_temp_buffer_required(struct usb_hcd *hcd,
> >>
> >> static void xhci_unmap_temp_buf(struct usb_hcd *hcd, struct urb *urb)
> >> {
> >> - unsigned int len;
> >> unsigned int buf_len;
> >> enum dma_data_direction dir;
> >>
> >> @@ -1351,7 +1350,7 @@ static void xhci_unmap_temp_buf(struct usb_hcd *hcd, struct urb *urb)
> >> dir);
> >>
> >> if (usb_urb_dir_in(urb))
> >> - len = sg_pcopy_from_buffer(urb->sg, urb->num_sgs,
> >> + sg_pcopy_from_buffer(urb->sg, urb->num_sgs,
> >> urb->transfer_buffer,
> >> buf_len,
> >> 0);
> >
> > SHouldn't this be checked instead of ignored?
> >
>
> Hi, Greg.
> Considering your tips I checked sg_pcopy_from_buffer(). it copys data
> from urb->transfer_buffer to urb->sg, and only returns 0 or the
> 'number of copied bytes', and seems to has no other exception branchs
> that need to be checked. So I think it should be ingnored.
Why should you not check that the number of bytes was copied properly?
thanks,
greg k-h
