From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3r3HTc2bX8zDq9s for ; Mon, 9 May 2016 19:41:56 +1000 (AEST) Message-ID: <1462786915.5531.3.camel@ellerman.id.au> Subject: Re: [PATCH 2/2] powerpc: Update of_remove_property() call sites to remove null checking From: Michael Ellerman To: Suraj Jitindar Singh , Tyrel Datwyler , devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: grant.likely@linaro.org, frowand.list@gmail.com, robh+dt@kernel.org, paulus@samba.org Date: Mon, 09 May 2016 19:41:55 +1000 In-Reply-To: <572C08DB.9000109@gmail.com> References: <1461821695-19204-1-git-send-email-sjitindarsingh@gmail.com> <1461821695-19204-2-git-send-email-sjitindarsingh@gmail.com> <57292702.5070507@linux.vnet.ibm.com> <1462431031.12473.3.camel@ellerman.id.au> <572C08DB.9000109@gmail.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2016-05-06 at 13:00 +1000, Suraj Jitindar Singh wrote: > On 05/05/16 16:50, Michael Ellerman wrote: > > On Tue, 2016-05-03 at 15:32 -0700, Tyrel Datwyler wrote: > > > On 04/27/2016 10:34 PM, Suraj Jitindar Singh wrote: > > > > diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c > > > > index ceb18d3..a560a98 100644 > > > > --- a/arch/powerpc/platforms/pseries/mobility.c > > > > +++ b/arch/powerpc/platforms/pseries/mobility.c > > > > @@ -191,8 +191,8 @@ static int update_dt_node(__be32 phandle, s32 scope) > > > > break; > > > > > > > > case 0x80000000: > > > > - prop = of_find_property(dn, prop_name, NULL); > > > > - of_remove_property(dn, prop); > > > > + of_remove_property(dn, of_find_property(dn, > > > > + prop_name, NULL)); > > > > prop = NULL; > > > > break; > > > > > > > You haven't removed a NULL check here, as suggested by the changelog, > > > but instead made a cosmetic change to the code that still leaves behind > > > a now unnecessary "prop = NULL;" to bit rot. > > Yeah I think you're right. Though it's not very clear how prop is used in that > > function. > > I didn't delete the prop = NULL; initially as I didn't fully understand > how it was used in the rest of the function and the effect of deleting > it. Yeah, it's pretty convoluted. I don't think you can actually prove it's safe to remove the prop = NULL for arbitrary inputs. cheers