Re: [PATCH] ipheth: fix EOVERFLOW in ipheth_rcvbulk_callback

[Jan Kiszka]

On 01.02.22 06:14, Jakub Kicinski wrote:
> On Mon, 31 Jan 2022 19:58:14 +0100 Jan Kiszka wrote:
> > From: Georgi Valkov <gvalkov@xxxxxx>
> >
> > When rx_buf is allocated we need to account for IPHETH_IP_ALIGN,
> > which reduces the usable size by 2 bytes. Otherwise we have 1512
> > bytes usable instead of 1514, and if we receive more than 1512
> > bytes, ipheth_rcvbulk_callback is called with status -EOVERFLOW,
> > after which the driver malfunctiones and all communication stops.
> >
> > Resolves ipheth 2-1:4.2: ipheth_rcvbulk_callback: urb status: -75
> >
> > Fixes: f33d9e2b48a3 ("usbnet: ipheth: fix connectivity with iOS 14")
> > Signed-off-by: Georgi Valkov <gvalkov@xxxxxx>
> > Tested-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
>
> Hm, I'm starting to suspect this patch is cursed..
>
> > diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
> > index cd33955df0b6..6a769df0b421 100644
> > --- a/drivers/net/usb/ipheth.c
> > +++ b/drivers/net/usb/ipheth.c
> > @@ -121,7 +121,7 @@ static int ipheth_alloc_urbs(struct ipheth_device *iphone)
> >    	if (tx_buf == NULL)
>
> There is an extra space character at the start of each line of context.
>
> >    		goto free_rx_urb;
> >    
> > -	rx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE,
>
> But not on the changed lines.
>
> > +	rx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
> >    				    GFP_KERNEL, &rx_urb->transfer_dma);
> >    	if (rx_buf == NULL)
> >    		goto free_tx_buf;
> > @@ -146,7 +146,7 @@ static int ipheth_alloc_urbs(struct ipheth_device *iphone)
> >    
> >    static void ipheth_free_urbs(struct ipheth_device *iphone)
> >    {
> > -	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, iphone->rx_buf,
>
> Pretty clear here in how the opening bracket does not align after the -.
>
> > +	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN, iphone->rx_buf,
> >    			  iphone->rx_urb->transfer_dma);
> >    	usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, iphone->tx_buf,
> >    			  iphone->tx_urb->transfer_dma);
> > @@ -317,7 +317,7 @@ static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags)
> >    
> >    	usb_fill_bulk_urb(dev->rx_urb, udev,
> >    			  usb_rcvbulkpipe(udev, dev->bulk_in),
> > -			  dev->rx_buf, IPHETH_BUF_SIZE,
> > +			  dev->rx_buf, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
> >    			  ipheth_rcvbulk_callback,
> >    			  dev);
> >    	dev->rx_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

Sorry, a submission tool regressed here unnoticed (grrrr!). Will resend.

Jan

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