Re: [PATCH v3 3/3] usb: core: hcd: use map_urb_for_dma for single step set feature urb

[Alan Stern <stern@rowland.harvard.edu>]

On Fri, May 07, 2021 at 02:58:02PM +0800, Li Jun wrote:
> Use map_urb_for_dma() to improve the dma map code for single step
> set feature request urb in test mode.
> 
> Signed-off-by: Li Jun <jun.li@nxp.com>
> ---
> Change for v3:
> - Correct the error handling if map_urb_for_dma() fails.
> 
> change for v2:
> - Add this new patch to use map_urb_for_dma API to
>   replace both of dma_map_single() calls, suggested by
>   Jack Pham.
> 
>  drivers/usb/core/hcd.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index d7eb9f179ca6..fa72697f4829 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2159,16 +2159,11 @@ static struct urb *request_single_step_set_feature_urb(
>  	usb_get_urb(urb);
>  	atomic_inc(&urb->use_count);
>  	atomic_inc(&urb->dev->urbnum);
> -	urb->setup_dma = dma_map_single(
> -			hcd->self.sysdev,
> -			urb->setup_packet,
> -			sizeof(struct usb_ctrlrequest),
> -			DMA_TO_DEVICE);
> -	urb->transfer_dma = dma_map_single(
> -			hcd->self.sysdev,
> -			urb->transfer_buffer,
> -			urb->transfer_buffer_length,
> -			DMA_FROM_DEVICE);
> +	if (map_urb_for_dma(hcd, urb, GFP_KERNEL)) {
> +		usb_put_urb(urb);

You need to call usb_free_urb() here.

Alan Stern

> +		return NULL;
> +	}
> +
>  	urb->context = done;
>  	return urb;
>  }
> -- 
> 2.25.1
>