Revert "xen: add helpers to allocate unpopulated memory"

diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c b/drivers/gpu/drm/xen/xen_drm_front_gem.c
index 2f464ef2d53e..90945344daae 100644
--- a/drivers/gpu/drm/xen/xen_drm_front_gem.c
+++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c
@@ -18,7 +18,6 @@ 
 #include <drm/drm_probe_helper.h>
 
 #include <xen/balloon.h>
-#include <xen/xen.h>
 
 #include "xen_drm_front.h"
 #include "xen_drm_front_gem.h"
@@ -100,8 +99,8 @@  static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size)
 		 * allocate ballooned pages which will be used to map
 		 * grant references provided by the backend
 		 */
-		ret = xen_alloc_unpopulated_pages(xen_obj->num_pages,
-					          xen_obj->pages);
+		ret = alloc_xenballooned_pages(xen_obj->num_pages,
+					       xen_obj->pages);
 		if (ret < 0) {
 			DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n",
 				  xen_obj->num_pages, ret);
@@ -153,8 +152,8 @@  void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj)
 	} else {
 		if (xen_obj->pages) {
 			if (xen_obj->be_alloc) {
-				xen_free_unpopulated_pages(xen_obj->num_pages,
-							   xen_obj->pages);
+				free_xenballooned_pages(xen_obj->num_pages,
+							xen_obj->pages);
 				gem_free_pages_array(xen_obj);
 			} else {
 				drm_gem_put_pages(&xen_obj->base,
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 41645fe6ad48..ea6c1e7e3e42 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -325,14 +325,4 @@  config XEN_HAVE_VPMU
 config XEN_FRONT_PGDIR_SHBUF
 	tristate
 
-config XEN_UNPOPULATED_ALLOC
-	bool "Use unpopulated memory ranges for guest mappings"
-	depends on X86 && ZONE_DEVICE
-	default XEN_BACKEND || XEN_GNTDEV || XEN_DOM0
-	help
-	  Use unpopulated memory ranges in order to create mappings for guest
-	  memory regions, including grant maps and foreign pages. This avoids
-	  having to balloon out RAM regions in order to obtain physical memory
-	  space to create such mappings.
-
 endmenu
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index babdca808861..c25c9a699b48 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -41,4 +41,3 @@  xen-gntdev-$(CONFIG_XEN_GNTDEV_DMABUF)	+= gntdev-dmabuf.o
 xen-gntalloc-y				:= gntalloc.o
 xen-privcmd-y				:= privcmd.o privcmd-buf.o
 obj-$(CONFIG_XEN_FRONT_PGDIR_SHBUF)	+= xen-front-pgdir-shbuf.o
-obj-$(CONFIG_XEN_UNPOPULATED_ALLOC)	+= unpopulated-alloc.o
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index b57b2067ecbf..12d3a95bfdb4 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -653,7 +653,7 @@  void free_xenballooned_pages(int nr_pages, struct page **pages)
 }
 EXPORT_SYMBOL(free_xenballooned_pages);
 
-#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)
+#ifdef CONFIG_XEN_PV
 static void __init balloon_add_region(unsigned long start_pfn,
 				      unsigned long pages)
 {
@@ -707,7 +707,7 @@  static int __init balloon_init(void)
 	register_sysctl_table(xen_root);
 #endif
 
-#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)
+#ifdef CONFIG_XEN_PV
 	{
 		int i;
 
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 523dcdf39cc9..8d06bf1cc347 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -801,7 +801,7 @@  int gnttab_alloc_pages(int nr_pages, struct page **pages)
 {
 	int ret;
 
-	ret = xen_alloc_unpopulated_pages(nr_pages, pages);
+	ret = alloc_xenballooned_pages(nr_pages, pages);
 	if (ret < 0)
 		return ret;
 
@@ -836,7 +836,7 @@  EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
 void gnttab_free_pages(int nr_pages, struct page **pages)
 {
 	gnttab_pages_clear_private(nr_pages, pages);
-	xen_free_unpopulated_pages(nr_pages, pages);
+	free_xenballooned_pages(nr_pages, pages);
 }
 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index b0c73c58f987..63abe6c3642b 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -424,7 +424,7 @@  static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
 	if (pages == NULL)
 		return -ENOMEM;
 
-	rc = xen_alloc_unpopulated_pages(numpgs, pages);
+	rc = alloc_xenballooned_pages(numpgs, pages);
 	if (rc != 0) {
 		pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
 			numpgs, rc);
@@ -895,7 +895,7 @@  static void privcmd_close(struct vm_area_struct *vma)
 
 	rc = xen_unmap_domain_gfn_range(vma, numgfns, pages);
 	if (rc == 0)
-		xen_free_unpopulated_pages(numpgs, pages);
+		free_xenballooned_pages(numpgs, pages);
 	else
 		pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n",
 			numpgs, rc);
diff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c
deleted file mode 100644
index 8c512ea550bb..000000000000
--- a/drivers/xen/unpopulated-alloc.c
+++ /dev/null
@@ -1,200 +0,0 @@ 
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/errno.h>
-#include <linux/gfp.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/memremap.h>
-#include <linux/slab.h>
-
-#include <asm/page.h>
-
-#include <xen/page.h>
-#include <xen/xen.h>
-
-static DEFINE_MUTEX(list_lock);
-static LIST_HEAD(page_list);
-static unsigned int list_count;
-
-static int fill_list(unsigned int nr_pages)
-{
-	struct dev_pagemap *pgmap;
-	struct resource *res;
-	void *vaddr;
-	unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION);
-	int ret = -ENOMEM;
-
-	res = kzalloc(sizeof(*res), GFP_KERNEL);
-	if (!res)
-		return -ENOMEM;
-
-	pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL);
-	if (!pgmap)
-		goto err_pgmap;
-
-	pgmap->type = MEMORY_DEVICE_GENERIC;
-	res->name = "Xen scratch";
-	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
-
-	ret = allocate_resource(&iomem_resource, res,
-				alloc_pages * PAGE_SIZE, 0, -1,
-				PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
-	if (ret < 0) {
-		pr_err("Cannot allocate new IOMEM resource\n");
-		goto err_resource;
-	}
-
-	pgmap->range = (struct range) {
-		.start = res->start,
-		.end = res->end,
-	};
-	pgmap->nr_range = 1;
-	pgmap->owner = res;
-
-#ifdef CONFIG_XEN_HAVE_PVMMU
-        /*
-         * memremap will build page tables for the new memory so
-         * the p2m must contain invalid entries so the correct
-         * non-present PTEs will be written.
-         *
-         * If a failure occurs, the original (identity) p2m entries
-         * are not restored since this region is now known not to
-         * conflict with any devices.
-         */
-	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-		xen_pfn_t pfn = PFN_DOWN(res->start);
-
-		for (i = 0; i < alloc_pages; i++) {
-			if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
-				pr_warn("set_phys_to_machine() failed, no memory added\n");
-				ret = -ENOMEM;
-				goto err_memremap;
-			}
-                }
-	}
-#endif
-
-	vaddr = memremap_pages(pgmap, NUMA_NO_NODE);
-	if (IS_ERR(vaddr)) {
-		pr_err("Cannot remap memory range\n");
-		ret = PTR_ERR(vaddr);
-		goto err_memremap;
-	}
-
-	for (i = 0; i < alloc_pages; i++) {
-		struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);
-
-		BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i));
-		list_add(&pg->lru, &page_list);
-		list_count++;
-	}
-
-	return 0;
-
-err_memremap:
-	release_resource(res);
-err_resource:
-	kfree(pgmap);
-err_pgmap:
-	kfree(res);
-	return ret;
-}
-
-/**
- * xen_alloc_unpopulated_pages - alloc unpopulated pages
- * @nr_pages: Number of pages
- * @pages: pages returned
- * @return 0 on success, error otherwise
- */
-int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
-{
-	unsigned int i;
-	int ret = 0;
-
-	mutex_lock(&list_lock);
-	if (list_count < nr_pages) {
-		ret = fill_list(nr_pages - list_count);
-		if (ret)
-			goto out;
-	}
-
-	for (i = 0; i < nr_pages; i++) {
-		struct page *pg = list_first_entry_or_null(&page_list,
-							   struct page,
-							   lru);
-
-		BUG_ON(!pg);
-		list_del(&pg->lru);
-		list_count--;
-		pages[i] = pg;
-
-#ifdef CONFIG_XEN_HAVE_PVMMU
-		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-			ret = xen_alloc_p2m_entry(page_to_pfn(pg));
-			if (ret < 0) {
-				unsigned int j;
-
-				for (j = 0; j <= i; j++) {
-					list_add(&pages[j]->lru, &page_list);
-					list_count++;
-				}
-				goto out;
-			}
-		}
-#endif
-	}
-
-out:
-	mutex_unlock(&list_lock);
-	return ret;
-}
-EXPORT_SYMBOL(xen_alloc_unpopulated_pages);
-
-/**
- * xen_free_unpopulated_pages - return unpopulated pages
- * @nr_pages: Number of pages
- * @pages: pages to return
- */
-void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
-{
-	unsigned int i;
-
-	mutex_lock(&list_lock);
-	for (i = 0; i < nr_pages; i++) {
-		list_add(&pages[i]->lru, &page_list);
-		list_count++;
-	}
-	mutex_unlock(&list_lock);
-}
-EXPORT_SYMBOL(xen_free_unpopulated_pages);
-
-#ifdef CONFIG_XEN_PV
-static int __init init(void)
-{
-	unsigned int i;
-
-	if (!xen_domain())
-		return -ENODEV;
-
-	if (!xen_pv_domain())
-		return 0;
-
-	/*
-	 * Initialize with pages from the extra memory regions (see
-	 * arch/x86/xen/setup.c).
-	 */
-	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
-		unsigned int j;
-
-		for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {
-			struct page *pg =
-				pfn_to_page(xen_extra_mem[i].start_pfn + j);
-
-			list_add(&pg->lru, &page_list);
-			list_count++;
-		}
-	}
-
-	return 0;
-}
-subsys_initcall(init);
-#endif
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index fd80e318b99c..ef8b6ea8ecca 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -618,7 +618,7 @@  static int xenbus_map_ring_hvm(struct xenbus_device *dev,
 	bool leaked = false;
 	unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
 
-	err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages);
+	err = alloc_xenballooned_pages(nr_pages, node->hvm.pages);
 	if (err)
 		goto out_err;
 
@@ -659,7 +659,7 @@  static int xenbus_map_ring_hvm(struct xenbus_device *dev,
 			 addr, nr_pages);
  out_free_ballooned_pages:
 	if (!leaked)
-		xen_free_unpopulated_pages(nr_pages, node->hvm.pages);
+		free_xenballooned_pages(nr_pages, node->hvm.pages);
  out_err:
 	return err;
 }
@@ -860,7 +860,7 @@  static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr)
 			       info.addrs);
 	if (!rv) {
 		vunmap(vaddr);
-		xen_free_unpopulated_pages(nr_pages, node->hvm.pages);
+		free_xenballooned_pages(nr_pages, node->hvm.pages);
 	}
 	else
 		WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages);
diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 34742c6e189e..7b1077f0abcb 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -232,7 +232,7 @@  int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
 		kfree(pages);
 		return -ENOMEM;
 	}
-	rc = xen_alloc_unpopulated_pages(nr_pages, pages);
+	rc = alloc_xenballooned_pages(nr_pages, pages);
 	if (rc) {
 		pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", __func__,
 			nr_pages, rc);
@@ -249,7 +249,7 @@  int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
 	if (!vaddr) {
 		pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__,
 			nr_pages, rc);
-		xen_free_unpopulated_pages(nr_pages, pages);
+		free_xenballooned_pages(nr_pages, pages);
 		kfree(pages);
 		kfree(pfns);
 		return -ENOMEM;
diff --git a/include/xen/xen.h b/include/xen/xen.h
index 43efba045acc..19a72f591e2b 100644
--- a/include/xen/xen.h
+++ b/include/xen/xen.h
@@ -52,13 +52,4 @@  bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
 extern u64 xen_saved_max_mem_size;
 #endif
 
-#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
-int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages);
-void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages);
-#else
-#define xen_alloc_unpopulated_pages alloc_xenballooned_pages
-#define xen_free_unpopulated_pages free_xenballooned_pages
-#include <xen/balloon.h>
-#endif
-
 #endif	/* _XEN_XEN_H */