Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 30 Sep 2020 13:03:31 -0700
From:   Nicolin Chen <nicoleotsuka@gmail.com>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     thierry.reding@gmail.com, joro@8bytes.org, krzk@kernel.org,
        vdumpa@nvidia.com, jonathanh@nvidia.com,
        linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/3] iommu/tegra-smmu: Add PCI support
Message-ID: <20200930200331.GB2110@Asurada-Nvidia>
References: <20200930084258.25493-1-nicoleotsuka@gmail.com>
 <20200930084258.25493-4-nicoleotsuka@gmail.com>
 <0a308ee8-abf7-97e4-9814-2156ee56fe8b@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <0a308ee8-abf7-97e4-9814-2156ee56fe8b@gmail.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
Precedence: bulk

On Wed, Sep 30, 2020 at 05:53:20PM +0300, Dmitry Osipenko wrote:
> ...
> > +#ifdef CONFIG_PCI
> > +	if (!iommu_present(&pci_bus_type)) {
> 
> 
> In the previous reply you said that you're borrowing this check from the
> arm-smmu driver, but arm-smmu also has a similar check for
> platform_bus_type, while Tegra SMMU driver doesn't have it. Hence I'm
> objecting the necessity of having this check.
> 
> Please give a rationale for having this check in the code. And please
> note that cargo cult isn't a rationale to me.

Okay, okay....I will remove it upon testing.