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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cda1fbcd23sm701747085a.1.2026.03.13.11.46.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Mar 2026 11:46:24 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1w17Wh-00000007M3T-2Qkk; Fri, 13 Mar 2026 15:46:23 -0300 Date: Fri, 13 Mar 2026 15:46:23 -0300 From: Jason Gunthorpe To: Jonathan Cameron Cc: "Aneesh Kumar K.V (Arm)" , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Kevin Tian , Joerg Roedel , Will Deacon , Bjorn Helgaas , Dan Williams , Alexey Kardashevskiy , Samuel Ortiz , Xu Yilun , Suzuki K Poulose , Steven Price Subject: Re: [PATCH v2 3/3] iommufd/vdevice: add TSM guest request ioctl Message-ID: <20260313184623.GN1704121@ziepe.ca> References: <20260309111704.2330479-1-aneesh.kumar@kernel.org> <20260309111704.2330479-4-aneesh.kumar@kernel.org> <20260311214343.00004641@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260311214343.00004641@huawei.com> On Wed, Mar 11, 2026 at 09:43:43PM +0000, Jonathan Cameron wrote: > > + vdev = container_of(iommufd_get_object(ucmd->ictx, cmd->vdevice_id, > > + IOMMUFD_OBJ_VDEVICE), > > As in previous, can the object be PTR_ERR()? Maybe not, but I'd > be surprised if the static analysis tools are convinced. > This might work for now if obj is first element but that's not > elegant or matainable. The compiler enforces first element: #define __iommufd_object_alloc(ictx, ptr, type, obj) \ container_of(_iommufd_object_alloc( \ ictx, \ sizeof(*(ptr)) + BUILD_BUG_ON_ZERO( \ offsetof(typeof(*(ptr)), \ obj) != 0), \ type), \ typeof(*(ptr)), obj) I have a lovely little series https://github.com/jgunthorpe/linux/commits/container_of/ For this that I keep meaning to send but then never do Jason