[PATCH v3 15/15] vsock/virtio: reorder fields to reduce padding

Michael S. Tsirkin
2026-01-28T20:31:28Z

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.

Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

changes from v2:
move event_lock and event_run too, to keep
event things logically together, as suggested by
Stefano Garzarella.

Note: this is the only change in v3 and it's cosmetic, so I am
not reposting the whole patchset.

net/vmw_vsock/virtio_transport.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 999a0839726a..b333a7591b26 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -55,15 +55,6 @@ struct virtio_vsock {
int rx_buf_nr;
int rx_buf_max_nr;

- /* The following fields are protected by event_lock.
- * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
- */
- 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;

@@ -77,6 +68,15 @@ struct virtio_vsock {
*/
struct scatterlist *out_sgs[MAX_SKB_FRAGS + 1];
struct scatterlist out_bufs[MAX_SKB_FRAGS + 1];
+
+ /* The following fields are protected by event_lock.
+ * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
+ */
+ struct mutex event_lock;
+ bool event_run;
+ __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