Re: [PATCH] usb: dwc3: gadget: Fix request complete check

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sat, Dec 14, 2019 at 03:01:40AM +0000, Thinh Nguyen wrote:
> Hi Greg and Felipe,
> 
> Thinh Nguyen wrote:
> > We can only check for IN direction if the request had completed. For OUT
> > direction, it's perfectly fine that the host can send less than the
> > setup length. Let's return true fall all cases of OUT direction.
> >
> > Fixes: e0c42ce590fe ("usb: dwc3: gadget: simplify IOC handling")
> >
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
> > ---
> >   drivers/usb/dwc3/gadget.c | 7 +++++++
> >   1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index b3f8514d1f27..edc478c20846 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -2470,6 +2470,13 @@ static int dwc3_gadget_ep_reclaim_trb_linear(struct dwc3_ep *dep,
> >   
> >   static bool dwc3_gadget_ep_request_completed(struct dwc3_request *req)
> >   {
> > +	/*
> > +	 * For OUT direction, host may send less than the setup
> > +	 * length. Return true for all OUT requests.
> > +	 */
> > +	if (!req->direction)
> > +		return true;
> > +
> >   	return req->request.actual == req->request.length;
> >   }
> >   
> 
> Not sure if it's too late, but after Tejas's patch* that fixes the SG 
> check in dwc3, it exposes another issue. Without this patch, quite a few 
> function drivers will not work with dwc3.
> 
> If we can pick it up before the next merge, it'd be great.

What exactly breaks without this patch?  And how was the original patch
ever tested?

thanks,

greg k-h