Re: [PATCH 2/2] usb: composite: Fix bug: low byte of w_index is the usb interface number not the whole 2 bytes of w_index

[David Brownell]

On Wednesday 07 January 2009, Bryan Wu wrote:
> In some usb gadget driver, for example usb audio class device, the high
> byte of w_index is the entity id and low byte is the interface number.
> If we use the 2 bytes of w_index as the array number, we will get a
> wrong pointer or NULL pointer.
> 
> This patch fixes this issue.
> 
> Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx>

Acked-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>


> ---
>  drivers/usb/gadget/composite.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 363951e..5d11c29 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -683,6 +683,7 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
>  	struct usb_request		*req = cdev->req;
>  	int				value = -EOPNOTSUPP;
>  	u16				w_index = le16_to_cpu(ctrl->wIndex);
> +	u8				intf = w_index & 0xFF;
>  	u16				w_value = le16_to_cpu(ctrl->wValue);
>  	u16				w_length = le16_to_cpu(ctrl->wLength);
>  	struct usb_function		*f = NULL;
> @@ -769,7 +770,7 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
>  			goto unknown;
>  		if (!cdev->config || w_index >= MAX_CONFIG_INTERFACES)
>  			break;
> -		f = cdev->config->interface[w_index];
> +		f = cdev->config->interface[intf];
>  		if (!f)
>  			break;
>  		if (w_value && !f->set_alt)
> @@ -781,7 +782,7 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
>  			goto unknown;
>  		if (!cdev->config || w_index >= MAX_CONFIG_INTERFACES)
>  			break;
> -		f = cdev->config->interface[w_index];
> +		f = cdev->config->interface[intf];
>  		if (!f)
>  			break;
>  		/* lots of interfaces only need altsetting zero... */
> @@ -808,7 +809,7 @@ unknown:
>  		 */
>  		if ((ctrl->bRequestType & USB_RECIP_MASK)
>  				== USB_RECIP_INTERFACE) {
> -			f = cdev->config->interface[w_index];
> +			f = cdev->config->interface[intf];
>  			if (f && f->setup)
>  				value = f->setup(f, ctrl);
>  			else
> -- 
> 1.5.6
> 
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> 


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