[PATCH] vfio: pci: use kzalloc_flex

Rosen Penev
2026-03-26T02:38:05Z

Simplify allocation by using a flexible array member and kzalloc_flex.
Less memory management needed.

Use __counted_by for extra runtime analysis. Move assignment to after
allocation as required by __counted_by.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
drivers/vfio/pci/vfio_pci_dmabuf.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 3a803923141b..40e7e035a720 100644
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -14,12 +14,12 @@ struct vfio_pci_dma_buf {
struct vfio_pci_core_device *vdev;
struct list_head dmabufs_elm;
size_t size;
- struct phys_vec *phys_vec;
struct p2pdma_provider *provider;
u32 nr_ranges;
struct kref kref;
struct completion comp;
u8 revoked : 1;
+ struct phys_vec phys_vec[] __counted_by(nr_ranges);
};

static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf,
@@ -95,7 +95,6 @@ static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf)
up_write(&priv->vdev->memory_lock);
vfio_device_put_registration(&priv->vdev->vdev);
}
- kfree(priv->phys_vec);
kfree(priv);
}

@@ -258,33 +257,28 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
if (ret)
goto err_free_ranges;

- priv = kzalloc_obj(*priv);
+ priv = kzalloc_flex(*priv, phys_vec, get_dma_buf.nr_ranges);
if (!priv) {
ret = -ENOMEM;
goto err_free_ranges;
}
- priv->phys_vec = kzalloc_objs(*priv->phys_vec, get_dma_buf.nr_ranges);
- if (!priv->phys_vec) {
- ret = -ENOMEM;
- goto err_free_priv;
- }

- priv->vdev = vdev;
priv->nr_ranges = get_dma_buf.nr_ranges;
+ priv->vdev = vdev;
priv->size = length;
ret = vdev->pci_ops->get_dmabuf_phys(vdev, &priv->provider,
get_dma_buf.region_index,
priv->phys_vec, dma_ranges,
priv->nr_ranges);
if (ret)
- goto err_free_phys;
+ goto err_free_priv;

kfree(dma_ranges);
dma_ranges = NULL;

if (!vfio_device_try_get_registration(&vdev->vdev)) {
ret = -ENODEV;
- goto err_free_phys;
+ goto err_free_priv;
}

exp_info.ops = &vfio_pci_dmabuf_ops;
@@ -323,8 +317,6 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
dma_buf_put(priv->dmabuf);
err_dev_put:
vfio_device_put_registration(&vdev->vdev);
-err_free_phys:
- kfree(priv->phys_vec);
err_free_priv:
kfree(priv);
err_free_ranges:
--
2.53.0