On Thu, Sep 16, 2021 at 05:40:59PM -0600, Logan Gunthorpe wrote:
> +static void pci_p2pdma_unmap_mappings(void *data)
> +{
> + struct pci_dev *pdev = data;
> + struct pci_p2pdma *p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
> +
> + p2pdma->active = false;
> + synchronize_rcu();
> + unmap_mapping_range(p2pdma->inode->i_mapping, 0, 0, 1);
> + pci_p2pdma_free_mappings(p2pdma->inode->i_mapping);
> +}
If this is going to rely on unmap_mapping_range then GUP should also
reject this memory for FOLL_LONGTERM..
What along this control flow:
> + error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_unmap_mappings,
> + pdev);
Waits for all the page refcounts to go to zero?
Jason
