linux-kernel - Re: [PATCH RESEND] usb: gadget: udc: bdc: Remove unnecessary NULL checks in bdc_req

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Message-ID: <20200329144703.GA9720@ubuntu-m2-xlarge-x86>
Date:   Sun, 29 Mar 2020 07:47:03 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Felipe Balbi <balbi@...nel.org>
Cc:     Ashwini Pahuja <ashwini.linux@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH RESEND] usb: gadget: udc: bdc: Remove unnecessary NULL
 checks in bdc_req_complete

On Sun, Mar 29, 2020 at 10:43:54AM +0300, Felipe Balbi wrote:
> 
> Hi Nathan,
> 
> Nathan Chancellor <natechancellor@...il.com> writes:
> 
> > When building with Clang + -Wtautological-pointer-compare:
> >
> > drivers/usb/gadget/udc/bdc/bdc_ep.c:543:28: warning: comparison of
> > address of 'req->queue' equal to a null pointer is always false
> > [-Wtautological-pointer-compare]
> >         if (req == NULL  || &req->queue == NULL || &req->usb_req == NULL)
> >                              ~~~~~^~~~~    ~~~~
> > drivers/usb/gadget/udc/bdc/bdc_ep.c:543:51: warning: comparison of
> > address of 'req->usb_req' equal to a null pointer is always false
> > [-Wtautological-pointer-compare]
> >         if (req == NULL  || &req->queue == NULL || &req->usb_req == NULL)
> >                                                     ~~~~~^~~~~~~    ~~~~
> > 2 warnings generated.
> >
> > As it notes, these statements will always evaluate to false so remove
> > them.
> >
> > Fixes: efed421a94e6 ("usb: gadget: Add UDC driver for Broadcom USB3.0 device controller IP BDC")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/749
> > Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> 
> It's now in my queue for v5.8. It doesn't really look like a bug fix, so
> it's not going in during v5.7-rc
> 
> -- 
> balbi

Thank you for picking it up. It would be nice to see it in 5.7 since
we're enabling this warning and this is one of two outstanding
instances in -next and the other one's patch has been picked up plus the
patch itself is rather benign. Not to mention that I did send this patch
back in October. However, when it is merged into Linus' tree is
ultimately your call so I won't argue as long as it gets there
eventually.

Cheers,
Nathan