Hi,

<...>

<...>

+struct file *memfd_mkinaccessible(struct file *memfd)
+{
+       struct inaccessible_data *data;
+       struct address_space *mapping;
+       struct inode *inode;
+       struct file *file;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return ERR_PTR(-ENOMEM);
+
+       data->memfd = memfd;
+       mutex_init(&data->lock);
+       INIT_LIST_HEAD(&data->notifiers);
+
+       inode = alloc_anon_inode(inaccessible_mnt->mnt_sb);
+       if (IS_ERR(inode)) {
+               kfree(data);
+               return ERR_CAST(inode);
+       }
+
+       inode->i_mode |= S_IFREG;
+       inode->i_op = &inaccessible_iops;
+       inode->i_mapping->private_data = data;
+
+       file = alloc_file_pseudo(inode, inaccessible_mnt,
+                                "[memfd:inaccessible]", O_RDWR,
+                                &inaccessible_fops);
+       if (IS_ERR(file)) {
+               iput(inode);
+               kfree(data);

I think this might be missing a return at this point.

+       }
+
+       file->f_flags |= O_LARGEFILE;
+
+       mapping = memfd->f_mapping;
+       mapping_set_unevictable(mapping);
+       mapping_set_gfp_mask(mapping,
+                            mapping_gfp_mask(mapping) & ~__GFP_MOVABLE);
+
+       return file;
+}

Thanks,
/fuad

+
+void inaccessible_register_notifier(struct file *file,
+                                   struct inaccessible_notifier *notifier)
+{
+       struct inaccessible_data *data = file->f_mapping->private_data;
+
+       mutex_lock(&data->lock);
+       list_add(&notifier->list, &data->notifiers);
+       mutex_unlock(&data->lock);
+}
+EXPORT_SYMBOL_GPL(inaccessible_register_notifier);
+
+void inaccessible_unregister_notifier(struct file *file,
+                                     struct inaccessible_notifier *notifier)
+{
+       struct inaccessible_data *data = file->f_mapping->private_data;
+
+       mutex_lock(&data->lock);
+       list_del(&notifier->list);
+       mutex_unlock(&data->lock);
+}
+EXPORT_SYMBOL_GPL(inaccessible_unregister_notifier);
+
+int inaccessible_get_pfn(struct file *file, pgoff_t offset, pfn_t *pfn,
+                        int *order)
+{
+       struct inaccessible_data *data = file->f_mapping->private_data;
+       struct file *memfd = data->memfd;
+       struct page *page;
+       int ret;
+
+       ret = shmem_getpage(file_inode(memfd), offset, &page, SGP_WRITE);
+       if (ret)
+               return ret;
+
+       *pfn = page_to_pfn_t(page);
+       *order = thp_order(compound_head(page));
+       SetPageUptodate(page);
+       unlock_page(page);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(inaccessible_get_pfn);
+
+void inaccessible_put_pfn(struct file *file, pfn_t pfn)
+{
+       struct page *page = pfn_t_to_page(pfn);
+
+       if (WARN_ON_ONCE(!page))
+               return;
+
+       put_page(page);
+}
+EXPORT_SYMBOL_GPL(inaccessible_put_pfn);
--
2.25.1