Re: [PATCH] s390/vfio-ap: Replace one-element array with flexible array member

[Anthony Krowiak <akrowiak@linux.ibm.com>]

On 1/16/25 8:18 AM, Thorsten Blum wrote:
> Replace the deprecated one-element array with a modern flexible array
> member in the struct ap_matrix_dev.
>
> Use struct_size() to calculate the number of bytes to allocate for
> matrix_dev with a single mdev_type.
>
> Link: https://github.com/KSPP/linux/issues/79

LGTM:
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>

> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
>   drivers/s390/crypto/vfio_ap_drv.c     | 2 +-
>   drivers/s390/crypto/vfio_ap_private.h | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 67a807e2e75b..ea9ffa37f263 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -96,7 +96,7 @@ static int vfio_ap_matrix_dev_create(void)
>   	if (ret)
>   		goto bus_register_err;
>   
> -	matrix_dev = kzalloc(sizeof(*matrix_dev), GFP_KERNEL);
> +	matrix_dev = kzalloc(struct_size(matrix_dev, mdev_types, 1), GFP_KERNEL);
>   	if (!matrix_dev) {
>   		ret = -ENOMEM;
>   		goto matrix_alloc_err;
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index 437a161c8659..9aed8994f567 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -53,7 +53,7 @@ struct ap_matrix_dev {
>   	struct mutex guests_lock; /* serializes access to each KVM guest */
>   	struct mdev_parent parent;
>   	struct mdev_type mdev_type;
> -	struct mdev_type *mdev_types[1];
> +	struct mdev_type *mdev_types[];
>   };
>   
>   extern struct ap_matrix_dev *matrix_dev;