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14c5cebad5
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>
405 lines
11 KiB
C
405 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
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#include <linux/device.h>
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#include <linux/io.h>
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#include <linux/kasan.h>
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#include <linux/memory_hotplug.h>
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#include <linux/mm.h>
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#include <linux/pfn_t.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/types.h>
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#include <linux/wait_bit.h>
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#include <linux/xarray.h>
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static DEFINE_XARRAY(pgmap_array);
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#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
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#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
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#ifdef CONFIG_DEV_PAGEMAP_OPS
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DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
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EXPORT_SYMBOL(devmap_managed_key);
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static atomic_t devmap_managed_enable;
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static void devmap_managed_enable_put(void *data)
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{
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if (atomic_dec_and_test(&devmap_managed_enable))
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static_branch_disable(&devmap_managed_key);
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}
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static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
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{
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if (!pgmap->ops || !pgmap->ops->page_free) {
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WARN(1, "Missing page_free method\n");
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return -EINVAL;
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}
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if (atomic_inc_return(&devmap_managed_enable) == 1)
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static_branch_enable(&devmap_managed_key);
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return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
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}
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#else
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static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
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{
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return -EINVAL;
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}
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#endif /* CONFIG_DEV_PAGEMAP_OPS */
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static void pgmap_array_delete(struct resource *res)
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{
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xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
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NULL, GFP_KERNEL);
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synchronize_rcu();
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}
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static unsigned long pfn_first(struct dev_pagemap *pgmap)
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{
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return PHYS_PFN(pgmap->res.start) +
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vmem_altmap_offset(pgmap_altmap(pgmap));
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}
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static unsigned long pfn_end(struct dev_pagemap *pgmap)
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{
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const struct resource *res = &pgmap->res;
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return (res->start + resource_size(res)) >> PAGE_SHIFT;
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}
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static unsigned long pfn_next(unsigned long pfn)
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{
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if (pfn % 1024 == 0)
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cond_resched();
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return pfn + 1;
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}
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#define for_each_device_pfn(pfn, map) \
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for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
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static void dev_pagemap_kill(struct dev_pagemap *pgmap)
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{
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if (pgmap->ops && pgmap->ops->kill)
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pgmap->ops->kill(pgmap);
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else
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percpu_ref_kill(pgmap->ref);
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}
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static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)
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{
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if (pgmap->ops && pgmap->ops->cleanup) {
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pgmap->ops->cleanup(pgmap);
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} else {
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wait_for_completion(&pgmap->done);
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percpu_ref_exit(pgmap->ref);
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}
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}
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static void devm_memremap_pages_release(void *data)
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{
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struct dev_pagemap *pgmap = data;
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struct device *dev = pgmap->dev;
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struct resource *res = &pgmap->res;
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unsigned long pfn;
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int nid;
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dev_pagemap_kill(pgmap);
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for_each_device_pfn(pfn, pgmap)
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put_page(pfn_to_page(pfn));
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dev_pagemap_cleanup(pgmap);
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/* pages are dead and unused, undo the arch mapping */
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nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start)));
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mem_hotplug_begin();
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if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
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pfn = PHYS_PFN(res->start);
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__remove_pages(page_zone(pfn_to_page(pfn)), pfn,
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PHYS_PFN(resource_size(res)), NULL);
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} else {
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arch_remove_memory(nid, res->start, resource_size(res),
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pgmap_altmap(pgmap));
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kasan_remove_zero_shadow(__va(res->start), resource_size(res));
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}
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mem_hotplug_done();
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untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
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pgmap_array_delete(res);
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dev_WARN_ONCE(dev, pgmap->altmap.alloc,
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"%s: failed to free all reserved pages\n", __func__);
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}
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static void dev_pagemap_percpu_release(struct percpu_ref *ref)
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{
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struct dev_pagemap *pgmap =
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container_of(ref, struct dev_pagemap, internal_ref);
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complete(&pgmap->done);
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}
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/**
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* devm_memremap_pages - remap and provide memmap backing for the given resource
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* @dev: hosting device for @res
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* @pgmap: pointer to a struct dev_pagemap
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*
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* Notes:
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* 1/ At a minimum the res and type members of @pgmap must be initialized
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* by the caller before passing it to this function
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*
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* 2/ The altmap field may optionally be initialized, in which case
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* PGMAP_ALTMAP_VALID must be set in pgmap->flags.
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*
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* 3/ The ref field may optionally be provided, in which pgmap->ref must be
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* 'live' on entry and will be killed and reaped at
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* devm_memremap_pages_release() time, or if this routine fails.
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*
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* 4/ res is expected to be a host memory range that could feasibly be
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* treated as a "System RAM" range, i.e. not a device mmio range, but
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* this is not enforced.
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*/
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void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
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{
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struct resource *res = &pgmap->res;
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struct dev_pagemap *conflict_pgmap;
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struct mhp_restrictions restrictions = {
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/*
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* We do not want any optional features only our own memmap
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*/
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.altmap = pgmap_altmap(pgmap),
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};
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pgprot_t pgprot = PAGE_KERNEL;
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int error, nid, is_ram;
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bool need_devmap_managed = true;
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switch (pgmap->type) {
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case MEMORY_DEVICE_PRIVATE:
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if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
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WARN(1, "Device private memory not supported\n");
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return ERR_PTR(-EINVAL);
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}
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if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
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WARN(1, "Missing migrate_to_ram method\n");
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return ERR_PTR(-EINVAL);
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}
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break;
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case MEMORY_DEVICE_FS_DAX:
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if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
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IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
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WARN(1, "File system DAX not supported\n");
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return ERR_PTR(-EINVAL);
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}
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break;
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case MEMORY_DEVICE_DEVDAX:
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case MEMORY_DEVICE_PCI_P2PDMA:
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need_devmap_managed = false;
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break;
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default:
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WARN(1, "Invalid pgmap type %d\n", pgmap->type);
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break;
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}
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if (!pgmap->ref) {
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if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))
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return ERR_PTR(-EINVAL);
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init_completion(&pgmap->done);
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error = percpu_ref_init(&pgmap->internal_ref,
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dev_pagemap_percpu_release, 0, GFP_KERNEL);
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if (error)
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return ERR_PTR(error);
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pgmap->ref = &pgmap->internal_ref;
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} else {
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if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {
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WARN(1, "Missing reference count teardown definition\n");
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return ERR_PTR(-EINVAL);
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}
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}
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if (need_devmap_managed) {
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error = devmap_managed_enable_get(dev, pgmap);
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if (error)
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return ERR_PTR(error);
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}
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conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
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if (conflict_pgmap) {
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dev_WARN(dev, "Conflicting mapping in same section\n");
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put_dev_pagemap(conflict_pgmap);
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error = -ENOMEM;
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goto err_array;
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}
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conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
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if (conflict_pgmap) {
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dev_WARN(dev, "Conflicting mapping in same section\n");
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put_dev_pagemap(conflict_pgmap);
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error = -ENOMEM;
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goto err_array;
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}
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is_ram = region_intersects(res->start, resource_size(res),
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IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
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if (is_ram != REGION_DISJOINT) {
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WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
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is_ram == REGION_MIXED ? "mixed" : "ram", res);
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error = -ENXIO;
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goto err_array;
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}
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pgmap->dev = dev;
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error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
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PHYS_PFN(res->end), pgmap, GFP_KERNEL));
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if (error)
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goto err_array;
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nid = dev_to_node(dev);
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if (nid < 0)
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nid = numa_mem_id();
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error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0,
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resource_size(res));
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if (error)
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goto err_pfn_remap;
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mem_hotplug_begin();
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/*
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* For device private memory we call add_pages() as we only need to
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* allocate and initialize struct page for the device memory. More-
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* over the device memory is un-accessible thus we do not want to
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* create a linear mapping for the memory like arch_add_memory()
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* would do.
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*
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* For all other device memory types, which are accessible by
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* the CPU, we do want the linear mapping and thus use
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* arch_add_memory().
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*/
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if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
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error = add_pages(nid, PHYS_PFN(res->start),
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PHYS_PFN(resource_size(res)), &restrictions);
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} else {
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error = kasan_add_zero_shadow(__va(res->start), resource_size(res));
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if (error) {
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mem_hotplug_done();
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goto err_kasan;
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}
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error = arch_add_memory(nid, res->start, resource_size(res),
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&restrictions);
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}
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if (!error) {
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struct zone *zone;
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zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
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move_pfn_range_to_zone(zone, PHYS_PFN(res->start),
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PHYS_PFN(resource_size(res)), restrictions.altmap);
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}
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mem_hotplug_done();
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if (error)
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goto err_add_memory;
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/*
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* Initialization of the pages has been deferred until now in order
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* to allow us to do the work while not holding the hotplug lock.
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*/
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memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
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PHYS_PFN(res->start),
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PHYS_PFN(resource_size(res)), pgmap);
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percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
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error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
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pgmap);
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if (error)
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return ERR_PTR(error);
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return __va(res->start);
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err_add_memory:
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kasan_remove_zero_shadow(__va(res->start), resource_size(res));
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err_kasan:
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untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
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err_pfn_remap:
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pgmap_array_delete(res);
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err_array:
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dev_pagemap_kill(pgmap);
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dev_pagemap_cleanup(pgmap);
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return ERR_PTR(error);
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}
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EXPORT_SYMBOL_GPL(devm_memremap_pages);
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void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
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{
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devm_release_action(dev, devm_memremap_pages_release, pgmap);
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}
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EXPORT_SYMBOL_GPL(devm_memunmap_pages);
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unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
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{
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/* number of pfns from base where pfn_to_page() is valid */
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if (altmap)
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return altmap->reserve + altmap->free;
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return 0;
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}
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void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
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{
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altmap->alloc -= nr_pfns;
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}
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/**
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* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
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* @pfn: page frame number to lookup page_map
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* @pgmap: optional known pgmap that already has a reference
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*
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* If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
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* is non-NULL but does not cover @pfn the reference to it will be released.
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*/
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struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
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struct dev_pagemap *pgmap)
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{
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resource_size_t phys = PFN_PHYS(pfn);
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/*
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* In the cached case we're already holding a live reference.
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*/
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if (pgmap) {
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if (phys >= pgmap->res.start && phys <= pgmap->res.end)
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return pgmap;
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put_dev_pagemap(pgmap);
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}
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/* fall back to slow path lookup */
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rcu_read_lock();
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pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
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if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
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pgmap = NULL;
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rcu_read_unlock();
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return pgmap;
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}
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EXPORT_SYMBOL_GPL(get_dev_pagemap);
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#ifdef CONFIG_DEV_PAGEMAP_OPS
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void __put_devmap_managed_page(struct page *page)
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{
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int count = page_ref_dec_return(page);
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/*
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* If refcount is 1 then page is freed and refcount is stable as nobody
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* holds a reference on the page.
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*/
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if (count == 1) {
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/* Clear Active bit in case of parallel mark_page_accessed */
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__ClearPageActive(page);
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__ClearPageWaiters(page);
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mem_cgroup_uncharge(page);
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page->pgmap->ops->page_free(page);
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} else if (!count)
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__put_page(page);
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}
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EXPORT_SYMBOL(__put_devmap_managed_page);
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#endif /* CONFIG_DEV_PAGEMAP_OPS */
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