Re: [PATCH v3] usb: dwc3: gadget: Simplify TRB reclaim logic by removing redundant 'chain' argument

SCHNEIDER Johannes
2025-06-29T08:45:49Z

Hoi Greg,

> > Now that the TRB reclaim logic always inspects the TRB's CHN (Chain) bit
> > directly to determine whether a TRB is part of a chain, the explicit
> > 'chain' parameter passed into dwc3_gadget_ep_reclaim_completed_trb()
> > is no longer necessary.
> >
> > This cleanup simplifies the reclaim code by avoiding duplication of
> > chain state tracking, and makes the reclaim logic rely entirely on the
> > hardware descriptor flags — which are already present and accurate at
> > this stage.
> >
> > No functional changes intended.
> >
> > Signed-off-by: Johannes Schneider <johannes.schneider@leica-geosystems.com>
> > Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> > ---
> > v3: no changes, re-submission as single patch
> > v2: no changes to the patch, "faulty" re-submission
> > v1: initial submission as part of a series
> > Link:
> >
> > drivers/usb/dwc3/gadget.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 99fbd29d8f46..a4a2bf273f94 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -3497,7 +3497,7 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
> >
> > static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
> > struct dwc3_request *req, struct dwc3_trb *trb,
> > - const struct dwc3_event_depevt *event, int status, int chain)
> > + const struct dwc3_event_depevt *event, int status)
> > {
> > unsigned int count;
> >
> > @@ -3549,7 +3549,8 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
> > if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN)
> > return 1;
> >
> > - if (event->status & DEPEVT_STATUS_SHORT && !chain)
> > + if (event->status & DEPEVT_STATUS_SHORT &&
> > + !(trb->ctrl & DWC3_TRB_CTRL_CHN))
> > return 1;
> >
> > if ((trb->ctrl & DWC3_TRB_CTRL_ISP_IMI) &&
> > @@ -3576,8 +3577,7 @@ static int dwc3_gadget_ep_reclaim_trb_sg(struct dwc3_ep *dep,
> > trb = &dep->trb_pool[dep->trb_dequeue];
> >
> > ret = dwc3_gadget_ep_reclaim_completed_trb(dep, req,
> > - trb, event, status,
> > - !!(trb->ctrl & DWC3_TRB_CTRL_CHN));
> > + trb, event, status);
> > if (ret)
> > break;
> > }
> > --
> > 2.43.0
> >
>
> Applying just this patch I get:
>
> CC [M] drivers/usb/dwc3/gadget.o
> drivers/usb/dwc3/gadget.c: In function ‘dwc3_gadget_ep_reclaim_completed_trb’:
> drivers/usb/dwc3/gadget.c:3517:13: error: ‘chain’ undeclared (first use in this function)
> 3517 | if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO))
> | ^~~~~
> drivers/usb/dwc3/gadget.c:3517:13: note: each undeclared identifier is reported only once for each function it appears in
>
> So that's not going to work :(
>

Oh - sorry! i shouldn't have pulled the initial series apart :-(

I'll re-submit both patches together as v4 (this time both with cc-stable)
... without b4 to have a new mail tread

Thanks for the patience
Gruß
Johannes