Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 28 Feb 2022 15:06:21 -0700
From:   Alex Williamson <alex.williamson@redhat.com>
To:     Lu Baolu <baolu.lu@linux.intel.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joerg Roedel <joro@8bytes.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Christoph Hellwig <hch@infradead.org>,
        Kevin Tian <kevin.tian@intel.com>,
        Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Dan Williams <dan.j.williams@intel.com>, rafael@kernel.org,
        Diana Craciun <diana.craciun@oss.nxp.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Eric Auger <eric.auger@redhat.com>,
        Liu Yi L <yi.l.liu@intel.com>,
        Jacob jun Pan <jacob.jun.pan@intel.com>,
        Chaitanya Kulkarni <kch@nvidia.com>,
        Stuart Yoder <stuyoder@gmail.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Li Yang <leoyang.li@nxp.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 08/11] vfio: Remove use of vfio_group_viable()
Message-ID: <20220228150621.5984595b.alex.williamson@redhat.com>
In-Reply-To: <20220228005056.599595-9-baolu.lu@linux.intel.com>
References: <20220228005056.599595-1-baolu.lu@linux.intel.com>
        <20220228005056.599595-9-baolu.lu@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Mon, 28 Feb 2022 08:50:53 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> As DMA ownership is claimed for the iommu group when a VFIO group is
> added to a VFIO container, the VFIO group viability is guaranteed as long
> as group->container_users > 0. Remove those unnecessary group viability
> checks which are only hit when group->container_users is not zero.
> 
> The only remaining reference is in GROUP_GET_STATUS, which could be called
> at any time when group fd is valid. Here we just replace the
> vfio_group_viable() by directly calling IOMMU core to get viability status.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/vfio/vfio.c | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)

Acked-by: Alex Williamson <alex.williamson@redhat.com>