[Cc +Leon] On Wed, 25 Mar 2026 19:37:47 -0700 Rosen Penev <[email protected]> wrote:
> 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. I don't understand this statement, nr_ranges was previously set after the allocation of phys_vec. The only reordering was relative to setting vdev, but that appears arbitrary. In fact, we don't need to explicitly set the __counted_by variable at all, kzalloc_flex() handles that. So if anything, it's now redundant. Leon, any other comments? This should have a v2 removing the redundancy and fixing the commit log. NB. This will be a bit messy to merge since kref and completion exist in linux-next via drm, but maybe Linus will consolidate the hole in the structure when he resolves it. Thanks, Alex > > Signed-off-by: Rosen Penev <[email protected]> > --- > 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:
