Re: [PATCH] usb: xhci: call dma_unmap_single in error paths

[Sascha Hauer <sha@pengutronix.de>]

On Tue, Jan 09, 2024 at 01:02:01PM +0100, Ahmad Fatoum wrote:
> xHCI ring handling maps buffers prior to DMA and unmaps them on success,
> but leaves them mapped in the error case. This leads to buffers being
> remapped again triggering a CONFIG_DMA_API_DEBUG warning along with
> a stack trace:
> 
>   WARNING: dwc3 2f00000.usb@2f00000.of: from-device mapping 0xbdfa0000+0x800: duplicate mapping
> 
> Fix this by unmapping the code in the error case too. This is ok to do,
> because in the first instace, DMA hasn't been enabled yet and in the
> others abort_td() called beforehand terminates it.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/usb/host/xhci-ring.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 995772f92722..547047305dd0 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -639,8 +639,10 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
>  	 */
>  	ret = prepare_ring(ctrl, ring,
>  			   le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		dma_unmap_single(ctrl->host.hw_dev, map, length, direction);
>  		return ret;
> +	}
>  
>  	/*
>  	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
> @@ -725,6 +727,7 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
>  		abort_td(udev, ep_index);
>  		udev->status = USB_ST_NAK_REC;  /* closest thing to a timeout */
>  		udev->act_len = 0;
> +		dma_unmap_single(ctrl->host.hw_dev, map, length, direction);
>  		return -ETIMEDOUT;
>  	}
>  	field = le32_to_cpu(event->trans_event.flags);
> @@ -967,5 +970,6 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
>  	abort_td(udev, ep_index);
>  	udev->status = USB_ST_NAK_REC;
>  	udev->act_len = 0;
> +	dma_unmap_single(ctrl->host.hw_dev, map, length, direction);
>  	return -ETIMEDOUT;
>  }
> -- 
> 2.39.2
> 
> 
> 

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