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Thu, 27 May 2021 04:06:19 -0700 (PDT) Date: Thu, 27 May 2021 12:06:11 +0100 From: Lee Jones To: Mathias Nyman Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Mathias Nyman , linux-usb@vger.kernel.org Subject: Re: [PATCH 17/24] usb: host: xhci: Remove unused variable 'len' Message-ID: <20210527110611.GK543307@dell> References: <20210526130037.856068-1-lee.jones@linaro.org> <20210526130037.856068-18-lee.jones@linaro.org> <20210527081609.GF543307@dell> <5958f870-1834-3132-a729-2b26a84349ea@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5958f870-1834-3132-a729-2b26a84349ea@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, 27 May 2021, Mathias Nyman wrote: > On 27.5.2021 11.16, Lee Jones wrote: > > On Thu, 27 May 2021, Greg Kroah-Hartman wrote: > > > >> On Wed, May 26, 2021 at 02:00:30PM +0100, Lee Jones wrote: > >>> Fixes the following W=1 kernel build warning(s): > >>> > >>> drivers/usb/host/xhci.c: In function ‘xhci_unmap_temp_buf’: > >>> drivers/usb/host/xhci.c:1349:15: warning: variable ‘len’ set but not used [-Wunused-but-set-variable] > >>> > >>> Cc: Mathias Nyman > >>> Cc: Greg Kroah-Hartman > >>> Cc: linux-usb@vger.kernel.org > >>> Signed-off-by: Lee Jones > >>> --- > >>> drivers/usb/host/xhci.c | 9 ++++----- > >>> 1 file changed, 4 insertions(+), 5 deletions(-) > >>> > >>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > >>> index 27283654ca080..ac2a7d4288883 100644 > >>> --- a/drivers/usb/host/xhci.c > >>> +++ b/drivers/usb/host/xhci.c > >>> @@ -1346,7 +1346,6 @@ 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; > >>> > >>> @@ -1362,10 +1361,10 @@ 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, > >>> - urb->transfer_buffer, > >>> - buf_len, > >>> - 0); > >>> + sg_pcopy_from_buffer(urb->sg, urb->num_sgs, > >>> + urb->transfer_buffer, > >>> + buf_len, > >>> + 0); > >> > >> Sorry, but no, I keep rejecting this over and over, it needs to handle > >> the error handling properly and not paper over it like this :( > > > > Will fix. > > > >> All the bots keep tripping up on it, you are not alone. > > > > This is getting a lot of attention. Something like this should fix it: > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > index 27283654ca08..306ab81421fd 100644 > --- a/drivers/usb/host/xhci.c > +++ b/drivers/usb/host/xhci.c > @@ -1361,12 +1361,16 @@ static void xhci_unmap_temp_buf(struct usb_hcd *hcd, struct urb *urb) > urb->transfer_buffer_length, > dir); > > - if (usb_urb_dir_in(urb)) > + if (usb_urb_dir_in(urb)) { > len = sg_pcopy_from_buffer(urb->sg, urb->num_sgs, > urb->transfer_buffer, > buf_len, > 0); > - > + if (len != buf_len) { > + xhci_dbg(xhci, "Copy from tmp buf to urb sg list failed\n"); > + urb->actual_length = len; > + } > + } > urb->transfer_flags &= ~URB_DMA_MAP_SINGLE; > kfree(urb->transfer_buffer); > urb->transfer_buffer = NULL; > > urb->actual_length is now properly set. > The debug level message will help me find the cause if we ever need > to debug oddly behaving devices. > > Note this is a very rarly taken codepath for quirky xHC harware that > can't handle a specific sequence of buffer lengths queued. > > I can write a proper commit message and push this forward Okay by me. -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog