From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH 1/1] iommu: to avoid an unnecessary assignment Date: Fri, 3 Feb 2017 11:34:38 +0000 Message-ID: <12dad1b8-1a5b-889b-c272-dbf8eda3b00a@arm.com> References: <1486114502-10984-1-git-send-email-thunder.leizhen@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1486114502-10984-1-git-send-email-thunder.leizhen-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Zhen Lei , Joerg Roedel , iommu , linux-kernel Cc: Xinwei Hu , Zefan Li , Tianhong Ding , Hanjun Guo List-Id: iommu@lists.linux-foundation.org On 03/02/17 09:35, Zhen Lei wrote: > Move the assignment statement into if branch above, where it only > needs to be. > > Signed-off-by: Zhen Lei > --- > drivers/iommu/iommu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index dbe7f65..b231400 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1714,13 +1714,14 @@ int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids) > fwspec = krealloc(dev->iommu_fwspec, size, GFP_KERNEL); > if (!fwspec) > return -ENOMEM; > + > + dev->iommu_fwspec = fwspec; > } > > for (i = 0; i < num_ids; i++) > fwspec->ids[fwspec->num_ids + i] = ids[i]; > > fwspec->num_ids += num_ids; > - dev->iommu_fwspec = fwspec; Strictly, it was done here because I like following transactional idioms, i.e. at any point dev->fwspec is either the old one or the fully-initialised new one. However, since the state of the new one immediately after realloc isn't uninitialised, but still directly equivalent to the old one, I don't see an issue with moving the assignemnt there, plus it does avoid a redundant reassignment the first time through. Reviewed-by: Robin Murphy > return 0; > } > EXPORT_SYMBOL_GPL(iommu_fwspec_add_ids); > -- > 2.5.0 > > > _______________________________________________ > iommu mailing list > iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu >