memremap: move from kernel/ to mm/

memremap.c implements MM functionality for ZONE_DEVICE, so it really
should be in the mm/ directory, not the kernel/ one.

Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 0 insertions, 406 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index a8d923b5481b..ef0d95a190b4 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -111,7 +111,6 @@ obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
 obj-$(CONFIG_TORTURE_TEST) += torture.o
 
 obj-$(CONFIG_HAS_IOMEM) += iomem.o
-obj-$(CONFIG_ZONE_DEVICE) += memremap.o
 obj-$(CONFIG_RSEQ) += rseq.o
 
 obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o
diff --git a/kernel/memremap.c b/kernel/memremap.c
deleted file mode 100644
index 6ee03a816d67..000000000000
--- a/kernel/memremap.c
+++ /dev/null
@@ -1,405 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
-#include <linux/device.h>
-#include <linux/io.h>
-#include <linux/kasan.h>
-#include <linux/memory_hotplug.h>
-#include <linux/mm.h>
-#include <linux/pfn_t.h>
-#include <linux/swap.h>
-#include <linux/swapops.h>
-#include <linux/types.h>
-#include <linux/wait_bit.h>
-#include <linux/xarray.h>
-
-static DEFINE_XARRAY(pgmap_array);
-#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
-#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
-
-#ifdef CONFIG_DEV_PAGEMAP_OPS
-DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
-EXPORT_SYMBOL(devmap_managed_key);
-static atomic_t devmap_managed_enable;
-
-static void devmap_managed_enable_put(void *data)
-{
-	if (atomic_dec_and_test(&devmap_managed_enable))
-		static_branch_disable(&devmap_managed_key);
-}
-
-static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
-{
-	if (!pgmap->ops || !pgmap->ops->page_free) {
-		WARN(1, "Missing page_free method\n");
-		return -EINVAL;
-	}
-
-	if (atomic_inc_return(&devmap_managed_enable) == 1)
-		static_branch_enable(&devmap_managed_key);
-	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
-}
-#else
-static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
-{
-	return -EINVAL;
-}
-#endif /* CONFIG_DEV_PAGEMAP_OPS */
-
-static void pgmap_array_delete(struct resource *res)
-{
-	xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
-			NULL, GFP_KERNEL);
-	synchronize_rcu();
-}
-
-static unsigned long pfn_first(struct dev_pagemap *pgmap)
-{
-	return PHYS_PFN(pgmap->res.start) +
-		vmem_altmap_offset(pgmap_altmap(pgmap));
-}
-
-static unsigned long pfn_end(struct dev_pagemap *pgmap)
-{
-	const struct resource *res = &pgmap->res;
-
-	return (res->start + resource_size(res)) >> PAGE_SHIFT;
-}
-
-static unsigned long pfn_next(unsigned long pfn)
-{
-	if (pfn % 1024 == 0)
-		cond_resched();
-	return pfn + 1;
-}
-
-#define for_each_device_pfn(pfn, map) \
-	for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
-
-static void dev_pagemap_kill(struct dev_pagemap *pgmap)
-{
-	if (pgmap->ops && pgmap->ops->kill)
-		pgmap->ops->kill(pgmap);
-	else
-		percpu_ref_kill(pgmap->ref);
-}
-
-static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)
-{
-	if (pgmap->ops && pgmap->ops->cleanup) {
-		pgmap->ops->cleanup(pgmap);
-	} else {
-		wait_for_completion(&pgmap->done);
-		percpu_ref_exit(pgmap->ref);
-	}
-}
-
-static void devm_memremap_pages_release(void *data)
-{
-	struct dev_pagemap *pgmap = data;
-	struct device *dev = pgmap->dev;
-	struct resource *res = &pgmap->res;
-	unsigned long pfn;
-	int nid;
-
-	dev_pagemap_kill(pgmap);
-	for_each_device_pfn(pfn, pgmap)
-		put_page(pfn_to_page(pfn));
-	dev_pagemap_cleanup(pgmap);
-
-	/* pages are dead and unused, undo the arch mapping */
-	nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start)));
-
-	mem_hotplug_begin();
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
-		pfn = PHYS_PFN(res->start);
-		__remove_pages(page_zone(pfn_to_page(pfn)), pfn,
-				 PHYS_PFN(resource_size(res)), NULL);
-	} else {
-		arch_remove_memory(nid, res->start, resource_size(res),
-				pgmap_altmap(pgmap));
-		kasan_remove_zero_shadow(__va(res->start), resource_size(res));
-	}
-	mem_hotplug_done();
-
-	untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
-	pgmap_array_delete(res);
-	dev_WARN_ONCE(dev, pgmap->altmap.alloc,
-		      "%s: failed to free all reserved pages\n", __func__);
-}
-
-static void dev_pagemap_percpu_release(struct percpu_ref *ref)
-{
-	struct dev_pagemap *pgmap =
-		container_of(ref, struct dev_pagemap, internal_ref);
-
-	complete(&pgmap->done);
-}
-
-/**
- * devm_memremap_pages - remap and provide memmap backing for the given resource
- * @dev: hosting device for @res
- * @pgmap: pointer to a struct dev_pagemap
- *
- * Notes:
- * 1/ At a minimum the res and type members of @pgmap must be initialized
- *    by the caller before passing it to this function
- *
- * 2/ The altmap field may optionally be initialized, in which case
- *    PGMAP_ALTMAP_VALID must be set in pgmap->flags.
- *
- * 3/ The ref field may optionally be provided, in which pgmap->ref must be
- *    'live' on entry and will be killed and reaped at
- *    devm_memremap_pages_release() time, or if this routine fails.
- *
- * 4/ res is expected to be a host memory range that could feasibly be
- *    treated as a "System RAM" range, i.e. not a device mmio range, but
- *    this is not enforced.
- */
-void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
-{
-	struct resource *res = &pgmap->res;
-	struct dev_pagemap *conflict_pgmap;
-	struct mhp_restrictions restrictions = {
-		/*
-		 * We do not want any optional features only our own memmap
-		 */
-		.altmap = pgmap_altmap(pgmap),
-	};
-	pgprot_t pgprot = PAGE_KERNEL;
-	int error, nid, is_ram;
-	bool need_devmap_managed = true;
-
-	switch (pgmap->type) {
-	case MEMORY_DEVICE_PRIVATE:
-		if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
-			WARN(1, "Device private memory not supported\n");
-			return ERR_PTR(-EINVAL);
-		}
-		if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
-			WARN(1, "Missing migrate_to_ram method\n");
-			return ERR_PTR(-EINVAL);
-		}
-		break;
-	case MEMORY_DEVICE_FS_DAX:
-		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
-		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
-			WARN(1, "File system DAX not supported\n");
-			return ERR_PTR(-EINVAL);
-		}
-		break;
-	case MEMORY_DEVICE_DEVDAX:
-	case MEMORY_DEVICE_PCI_P2PDMA:
-		need_devmap_managed = false;
-		break;
-	default:
-		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
-		break;
-	}
-
-	if (!pgmap->ref) {
-		if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))
-			return ERR_PTR(-EINVAL);
-
-		init_completion(&pgmap->done);
-		error = percpu_ref_init(&pgmap->internal_ref,
-				dev_pagemap_percpu_release, 0, GFP_KERNEL);
-		if (error)
-			return ERR_PTR(error);
-		pgmap->ref = &pgmap->internal_ref;
-	} else {
-		if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {
-			WARN(1, "Missing reference count teardown definition\n");
-			return ERR_PTR(-EINVAL);
-		}
-	}
-
-	if (need_devmap_managed) {
-		error = devmap_managed_enable_get(dev, pgmap);
-		if (error)
-			return ERR_PTR(error);
-	}
-
-	conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
-	if (conflict_pgmap) {
-		dev_WARN(dev, "Conflicting mapping in same section\n");
-		put_dev_pagemap(conflict_pgmap);
-		error = -ENOMEM;
-		goto err_array;
-	}
-
-	conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
-	if (conflict_pgmap) {
-		dev_WARN(dev, "Conflicting mapping in same section\n");
-		put_dev_pagemap(conflict_pgmap);
-		error = -ENOMEM;
-		goto err_array;
-	}
-
-	is_ram = region_intersects(res->start, resource_size(res),
-		IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
-
-	if (is_ram != REGION_DISJOINT) {
-		WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
-				is_ram == REGION_MIXED ? "mixed" : "ram", res);
-		error = -ENXIO;
-		goto err_array;
-	}
-
-	pgmap->dev = dev;
-
-	error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
-				PHYS_PFN(res->end), pgmap, GFP_KERNEL));
-	if (error)
-		goto err_array;
-
-	nid = dev_to_node(dev);
-	if (nid < 0)
-		nid = numa_mem_id();
-
-	error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0,
-			resource_size(res));
-	if (error)
-		goto err_pfn_remap;
-
-	mem_hotplug_begin();
-
-	/*
-	 * For device private memory we call add_pages() as we only need to
-	 * allocate and initialize struct page for the device memory. More-
-	 * over the device memory is un-accessible thus we do not want to
-	 * create a linear mapping for the memory like arch_add_memory()
-	 * would do.
-	 *
-	 * For all other device memory types, which are accessible by
-	 * the CPU, we do want the linear mapping and thus use
-	 * arch_add_memory().
-	 */
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
-		error = add_pages(nid, PHYS_PFN(res->start),
-				PHYS_PFN(resource_size(res)), &restrictions);
-	} else {
-		error = kasan_add_zero_shadow(__va(res->start), resource_size(res));
-		if (error) {
-			mem_hotplug_done();
-			goto err_kasan;
-		}
-
-		error = arch_add_memory(nid, res->start, resource_size(res),
-					&restrictions);
-	}
-
-	if (!error) {
-		struct zone *zone;
-
-		zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
-		move_pfn_range_to_zone(zone, PHYS_PFN(res->start),
-				PHYS_PFN(resource_size(res)), restrictions.altmap);
-	}
-
-	mem_hotplug_done();
-	if (error)
-		goto err_add_memory;
-
-	/*
-	 * Initialization of the pages has been deferred until now in order
-	 * to allow us to do the work while not holding the hotplug lock.
-	 */
-	memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
-				PHYS_PFN(res->start),
-				PHYS_PFN(resource_size(res)), pgmap);
-	percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
-
-	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
-			pgmap);
-	if (error)
-		return ERR_PTR(error);
-
-	return __va(res->start);
-
- err_add_memory:
-	kasan_remove_zero_shadow(__va(res->start), resource_size(res));
- err_kasan:
-	untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
- err_pfn_remap:
-	pgmap_array_delete(res);
- err_array:
-	dev_pagemap_kill(pgmap);
-	dev_pagemap_cleanup(pgmap);
-	return ERR_PTR(error);
-}
-EXPORT_SYMBOL_GPL(devm_memremap_pages);
-
-void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
-{
-	devm_release_action(dev, devm_memremap_pages_release, pgmap);
-}
-EXPORT_SYMBOL_GPL(devm_memunmap_pages);
-
-unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
-{
-	/* number of pfns from base where pfn_to_page() is valid */
-	if (altmap)
-		return altmap->reserve + altmap->free;
-	return 0;
-}
-
-void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
-{
-	altmap->alloc -= nr_pfns;
-}
-
-/**
- * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
- * @pfn: page frame number to lookup page_map
- * @pgmap: optional known pgmap that already has a reference
- *
- * If @pgmap is non-NULL and covers @pfn it will be returned as-is.  If @pgmap
- * is non-NULL but does not cover @pfn the reference to it will be released.
- */
-struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
-		struct dev_pagemap *pgmap)
-{
-	resource_size_t phys = PFN_PHYS(pfn);
-
-	/*
-	 * In the cached case we're already holding a live reference.
-	 */
-	if (pgmap) {
-		if (phys >= pgmap->res.start && phys <= pgmap->res.end)
-			return pgmap;
-		put_dev_pagemap(pgmap);
-	}
-
-	/* fall back to slow path lookup */
-	rcu_read_lock();
-	pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
-	if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
-		pgmap = NULL;
-	rcu_read_unlock();
-
-	return pgmap;
-}
-EXPORT_SYMBOL_GPL(get_dev_pagemap);
-
-#ifdef CONFIG_DEV_PAGEMAP_OPS
-void __put_devmap_managed_page(struct page *page)
-{
-	int count = page_ref_dec_return(page);
-
-	/*
-	 * If refcount is 1 then page is freed and refcount is stable as nobody
-	 * holds a reference on the page.
-	 */
-	if (count == 1) {
-		/* Clear Active bit in case of parallel mark_page_accessed */
-		__ClearPageActive(page);
-		__ClearPageWaiters(page);
-
-		mem_cgroup_uncharge(page);
-
-		page->pgmap->ops->page_free(page);
-	} else if (!count)
-		__put_page(page);
-}
-EXPORT_SYMBOL(__put_devmap_managed_page);
-#endif /* CONFIG_DEV_PAGEMAP_OPS */