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

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Date:   Mon, 30 Mar 2020 08:08:05 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Felipe Balbi <balbi@...nel.org>
Cc:     Nathan Chancellor <natechancellor@...il.com>,
        Ashwini Pahuja <ashwini.linux@...il.com>,
        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 07:43:52PM +0300, Felipe Balbi wrote:
> 
> Hi,
> 
> 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.
> 
> If Greg's okay with this patch going in during v5.7-rc, I can send it as
> a fix, no worries. Greg?

Yes, clang build warnings fixes are valid fixes for the -rc period, and
I take them into stable where needed as well.

thanks,

greg k-h