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

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Date:   Sun, 29 Mar 2020 19:43:52 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Nathan Chancellor <natechancellor@...il.com>
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


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?

-- 
balbi

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