Re: [RFC/PATCH v3 1/4] usb: Add usb_endpoint_descriptor to be partof the struct usb_ep

From: Alan Stern
Date: Mon Nov 01 2010 - 15:53:07 EST


On Mon, 1 Nov 2010, Tatyana Brokhman wrote:

> Change usb_ep_enable() prototype to use endpoint descriptor from usb_ep.
> This optimization spares the FDs from saving the endpoint chosen
> descriptor. This optimization is not full though. To fully exploit this
> change one needs to update all the UDCs as well since in the current
> implementation each of them saves the endpoint descriptor in it's
> internal (and extended) endpoint structure.
>
> Signed-off-by: Tatyana Brokhman <tlinder@xxxxxxxxxxxxxx>


> diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
> index a857b7a..edd8727 100644
> --- a/drivers/usb/gadget/file_storage.c
> +++ b/drivers/usb/gadget/file_storage.c
> @@ -2745,7 +2745,8 @@ static int enable_endpoint(struct fsg_dev *fsg, struct usb_ep *ep,
> int rc;
>
> ep->driver_data = fsg;
> - rc = usb_ep_enable(ep, d);
> + ep->desc = (struct usb_endpoint_descriptor *)d;
> + rc = usb_ep_enable(ep);
> if (rc)
> ERROR(fsg, "can't enable %s, result %d\n", ep->name, rc);
> return rc;

Instead of casting the variable, you should remove the "const"
qualifiers here and in the callers. After all, if usb_ep_enable is
going to change the descriptor then we shouldn't call it "const".

Alternatively, if usb_ep_enable _isn't_ going to change the descriptor
then perhaps the new pointer added to usb_ep should be declared
"const".

Alan Stern

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