Re: [PATCH net-next v21 01/13] virtio_pci: Remove supported_cap size build assert

"Michael S. Tsirkin" <[email protected]> Mon, 3 Aug 2026 11:59:12 -0400
Newsgroups dev.linux.lists.virtualization,org.kernel.vger.netdev
Message-ID <[email protected]>
patch is ok. commit log isnt:


supported_cap is not a thing.

better subj:

 remove supported_caps cache and build assert


On Mon, Aug 03, 2026 at 05:07:09PM +0300, Shahar Shitrit wrote:
> From: Daniel Jurgens <[email protected]>
> 
> The cap ID list can be more than 64 bits.

what does "can be" mean? I think what u mean
following patches make ....

> Remove the build assert.


> Also
> remove caching of the supported caps, it wasn't used.

it's not "also". in fact we remove supported_caps and then
the rest of the code handles data->supported_caps of any
size, transparently.


> Signed-off-by: Daniel Jurgens <[email protected]>
> Reviewed-by: Parav Pandit <[email protected]>
> Reviewed-by: Xuan Zhuo <[email protected]>
> Signed-off-by: Shahar Shitrit <[email protected]>
> ---
>  drivers/virtio/virtio_pci_common.h |  1 -
>  drivers/virtio/virtio_pci_modern.c | 10 +++-------
>  2 files changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
> index 8cd01de27baf..fc26e035e7a6 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -48,7 +48,6 @@ struct virtio_pci_admin_vq {
>  	/* Protects virtqueue access. */
>  	spinlock_t lock;
>  	u64 supported_cmds;
> -	u64 supported_caps;
>  	u8 max_dev_parts_objects;
>  	struct ida dev_parts_ida;
>  	/* Name of the admin queue: avq.$vq_index. */
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 6d8ae2a6a8ca..ef4a64eb9982 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -304,10 +304,10 @@ virtio_pci_admin_cmd_dev_parts_objects_enable(struct virtio_device *virtio_dev)
>  
>  static void virtio_pci_admin_cmd_cap_init(struct virtio_device *virtio_dev)
>  {
> -	struct virtio_pci_device *vp_dev = to_vp_device(virtio_dev);
>  	struct virtio_admin_cmd_query_cap_id_result *data;
>  	struct virtio_admin_cmd cmd = {};
>  	struct scatterlist result_sg;
> +	u64 caps;
>  	int ret;
>  
>  	data = kzalloc_obj(*data);
> @@ -323,12 +323,8 @@ static void virtio_pci_admin_cmd_cap_init(struct virtio_device *virtio_dev)
>  	if (ret)
>  		goto end;
>  
> -	/* Max number of caps fits into a single u64 */
> -	BUILD_BUG_ON(sizeof(data->supported_caps) > sizeof(u64));
> -
> -	vp_dev->admin_vq.supported_caps = le64_to_cpu(data->supported_caps[0]);
> -
> -	if (!(vp_dev->admin_vq.supported_caps & (1 << VIRTIO_DEV_PARTS_CAP)))
> +	caps = le64_to_cpu(data->supported_caps[0]);
> +	if (!(caps & BIT_ULL(VIRTIO_DEV_PARTS_CAP)))
>  		goto end;
>  
>  	virtio_pci_admin_cmd_dev_parts_objects_enable(virtio_dev);
> -- 
> 2.49.0