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

[Anthony Krowiak]

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 <akrow...@linux.ibm.com>

Signed-off-by: Thorsten Blum <thorsten.b...@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;