memremap: remove the data field in struct dev_pagemap

struct dev_pagemap is always embedded into a containing structure, so
there is no need to an additional private data field.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Tested-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

drivers/nvdimm/pmem.c

@@ -334,7 +334,7 @@ static void pmem_release_disk(void *__pmem)
 	put_disk(pmem->disk);
 }
 
-static void pmem_pagemap_page_free(struct page *page, void *data)
+static void pmem_pagemap_page_free(struct page *page)
 {
 	wake_up_var(&page->_refcount);
 }

include/linux/memremap.h

@@ -69,7 +69,7 @@ struct dev_pagemap_ops {
 	 * reach 0 refcount unless there is a refcount bug. This allows the
 	 * device driver to implement its own memory management.)
 	 */
-	void (*page_free)(struct page *page, void *data);
+	void (*page_free)(struct page *page);
 
 	/*
 	 * Transition the refcount in struct dev_pagemap to the dead state.
@@ -104,7 +104,6 @@ struct dev_pagemap {
 	struct resource res;
 	struct percpu_ref *ref;
 	struct device *dev;
-	void *data;
 	enum memory_type type;
 	u64 pci_p2pdma_bus_offset;
 	const struct dev_pagemap_ops *ops;

kernel/memremap.c

@@ -376,7 +376,7 @@ void __put_devmap_managed_page(struct page *page)
 
 		mem_cgroup_uncharge(page);
 
-		page->pgmap->ops->page_free(page, page->pgmap->data);
+		page->pgmap->ops->page_free(page);
 	} else if (!count)
 		__put_page(page);
 }

mm/hmm.c

@@ -1368,15 +1368,17 @@ static void hmm_devmem_ref_kill(struct dev_pagemap *pgmap)
 
 static vm_fault_t hmm_devmem_migrate_to_ram(struct vm_fault *vmf)
 {
-	struct hmm_devmem *devmem = vmf->page->pgmap->data;
+	struct hmm_devmem *devmem =
+		container_of(vmf->page->pgmap, struct hmm_devmem, pagemap);
 
 	return devmem->ops->fault(devmem, vmf->vma, vmf->address, vmf->page,
 			vmf->flags, vmf->pmd);
 }
 
-static void hmm_devmem_free(struct page *page, void *data)
+static void hmm_devmem_free(struct page *page)
 {
-	struct hmm_devmem *devmem = data;
+	struct hmm_devmem *devmem =
+		container_of(page->pgmap, struct hmm_devmem, pagemap);
 
 	devmem->ops->free(devmem, page);
 }
@@ -1442,7 +1444,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 	devmem->pagemap.ops = &hmm_pagemap_ops;
 	devmem->pagemap.altmap_valid = false;
 	devmem->pagemap.ref = &devmem->ref;
-	devmem->pagemap.data = devmem;
 
 	result = devm_memremap_pages(devmem->device, &devmem->pagemap);
 	if (IS_ERR(result))