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Thu, 08 Jan 2026 06:11:54 -0800 (PST) Received: from sgarzare-redhat ([193.207.223.215]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6507bf65ca0sm7641163a12.24.2026.01.08.06.11.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jan 2026 06:11:53 -0800 (PST) Date: Thu, 8 Jan 2026 15:11:36 +0100 From: Stefano Garzarella To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Cong Wang , Jonathan Corbet , Olivia Mackall , Herbert Xu , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Eugenio =?utf-8?B?UMOpcmV6?= , "James E.J. Bottomley" , "Martin K. Petersen" , Gerd Hoffmann , Xuan Zhuo , Marek Szyprowski , Robin Murphy , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Petr Tesarik , Leon Romanovsky , Jason Gunthorpe , Bartosz Golaszewski , linux-doc@vger.kernel.org, linux-crypto@vger.kernel.org, virtualization@lists.linux.dev, linux-scsi@vger.kernel.org, iommu@lists.linux.dev, kvm@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v2 13/15] vsock/virtio: reorder fields to reduce padding Message-ID: References: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Mon, Jan 05, 2026 at 03:23:41AM -0500, Michael S. Tsirkin wrote: >Reorder struct virtio_vsock fields to place the DMA buffer (event_list) >last. This eliminates the padding from aligning the struct size on >ARCH_DMA_MINALIGN. > >Signed-off-by: Michael S. Tsirkin >--- > net/vmw_vsock/virtio_transport.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > >diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >index ef983c36cb66..964d25e11858 100644 >--- a/net/vmw_vsock/virtio_transport.c >+++ b/net/vmw_vsock/virtio_transport.c >@@ -60,9 +60,7 @@ struct virtio_vsock { > */ > struct mutex event_lock; > bool event_run; >- __dma_from_device_group_begin(); >- struct virtio_vsock_event event_list[8]; >- __dma_from_device_group_end(); >+ > u32 guest_cid; > bool seqpacket_allow; > >@@ -76,6 +74,10 @@ struct virtio_vsock { > */ > struct scatterlist *out_sgs[MAX_SKB_FRAGS + 1]; > struct scatterlist out_bufs[MAX_SKB_FRAGS + 1]; >+ IIUC we would like to have these fields always on the bottom of this struct, so would be better to add a comment here to make sure we will not add other fields in the future after this? Maybe we should also add a comment about the `event_lock` requirement we have in the section above. Thanks, Stefano >+ __dma_from_device_group_begin(); >+ struct virtio_vsock_event event_list[8]; >+ __dma_from_device_group_end(); > }; > > static u32 virtio_transport_get_local_cid(void) >-- >MST >