Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Xiaomeng Tong <xiam0nd.tong@gmail.com>
To:     laurent.pinchart@ideasonboard.com
Cc:     linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        mchehab@kernel.org, ribalda@chromium.org, xiam0nd.tong@gmail.com
Subject: Re: [PATCH] uvc: fix missing check to determine if element is found in list
Date:   Tue, 29 Mar 2022 13:09:25 +0800
Message-Id: <20220329050925.15300-1-xiam0nd.tong@gmail.com>
In-Reply-To: <YjnKvQZot2wnljmW@pendragon.ideasonboard.com>
References: <YjnKvQZot2wnljmW@pendragon.ideasonboard.com>
Precedence: bulk

On Tue, 22 Mar 2022 15:10:21 +0200, Laurent Pinchart wrote:

> > > Fixes: d5e90b7a6cd1c ("[media] uvcvideo: Move to video_ioctl2")
> > > Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
> > > ---
> > >  drivers/media/usb/uvc/uvc_v4l2.c | 20 +++++++++++++-------
> > >  1 file changed, 13 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> > > index 711556d13d03..e7cdc01ad277 100644
> > > --- a/drivers/media/usb/uvc/uvc_v4l2.c
> > > +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> > > @@ -871,6 +871,7 @@ static int uvc_ioctl_enum_input(struct file *file, void *fh,
> > >         struct uvc_video_chain *chain = handle->chain;
> > >         const struct uvc_entity *selector = chain->selector;
> > >         struct uvc_entity *iterm = NULL;
> > > +       struct uvc_entity *it;
> > >         u32 index = input->index;
> > >         int pin = 0;
> > >
> > > @@ -878,22 +879,27 @@ static int uvc_ioctl_enum_input(struct file *file, void *fh,
> > >             (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) {
> > >                 if (index != 0)
> > >                         return -EINVAL;
> > > -               list_for_each_entry(iterm, &chain->entities, chain) {
> > > -                       if (UVC_ENTITY_IS_ITERM(iterm))
> > > +               list_for_each_entry(it, &chain->entities, chain) {
> > > +                       if (UVC_ENTITY_IS_ITERM(it)) {
> > > +                               iterm = it;
> > >                                 break;
> > > +                       }
> > >                 }
> > > -               pin = iterm->id;
> > > +               if (iterm)
> > > +                       pin = iterm->id;
> 
> You can drop this, pin is not used anymore in the rest of the function.
> 
> > >         } else if (index < selector->bNrInPins) {
> > >                 pin = selector->baSourceID[index];
> > > -               list_for_each_entry(iterm, &chain->entities, chain) {
> > > -                       if (!UVC_ENTITY_IS_ITERM(iterm))
> > > +               list_for_each_entry(it, &chain->entities, chain) {
> > > +                       if (!UVC_ENTITY_IS_ITERM(it))
> > >                                 continue;
> > > -                       if (iterm->id == pin)
> > > +                       if (it->id == pin) {
> 
> And here you could use
> 			if (it->id == selector->baSourceID[index]) {
> 
> and drop the local pin variable.
> 
> If you're fine with those small changes I can handle them when applying
> the patch to my tree.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Thank you, i have resend a Patch v2 with changes as you suggested, please check it.

--
Xiaomeng Tong