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534 lines
14 KiB
534 lines
14 KiB
// 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/mmzone.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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|
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static DEFINE_XARRAY(pgmap_array); |
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|
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/* |
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* The memremap() and memremap_pages() interfaces are alternately used |
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* to map persistent memory namespaces. These interfaces place different |
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* constraints on the alignment and size of the mapping (namespace). |
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* memremap() can map individual PAGE_SIZE pages. memremap_pages() can |
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* only map subsections (2MB), and at least one architecture (PowerPC) |
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* the minimum mapping granularity of memremap_pages() is 16MB. |
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* |
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* The role of memremap_compat_align() is to communicate the minimum |
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* arch supported alignment of a namespace such that it can freely |
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* switch modes without violating the arch constraint. Namely, do not |
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* allow a namespace to be PAGE_SIZE aligned since that namespace may be |
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* reconfigured into a mode that requires SUBSECTION_SIZE alignment. |
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*/ |
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#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN |
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unsigned long memremap_compat_align(void) |
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{ |
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return SUBSECTION_SIZE; |
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} |
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EXPORT_SYMBOL_GPL(memremap_compat_align); |
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#endif |
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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 void devmap_managed_enable_put(struct dev_pagemap *pgmap) |
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{ |
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if (pgmap->type == MEMORY_DEVICE_PRIVATE || |
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pgmap->type == MEMORY_DEVICE_FS_DAX) |
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static_branch_dec(&devmap_managed_key); |
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} |
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static void devmap_managed_enable_get(struct dev_pagemap *pgmap) |
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{ |
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if (pgmap->type == MEMORY_DEVICE_PRIVATE || |
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pgmap->type == MEMORY_DEVICE_FS_DAX) |
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static_branch_inc(&devmap_managed_key); |
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} |
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#else |
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static void devmap_managed_enable_get(struct dev_pagemap *pgmap) |
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{ |
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} |
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static void devmap_managed_enable_put(struct dev_pagemap *pgmap) |
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{ |
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} |
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#endif /* CONFIG_DEV_PAGEMAP_OPS */ |
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static void pgmap_array_delete(struct range *range) |
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{ |
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xa_store_range(&pgmap_array, PHYS_PFN(range->start), PHYS_PFN(range->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, int range_id) |
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{ |
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struct range *range = &pgmap->ranges[range_id]; |
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unsigned long pfn = PHYS_PFN(range->start); |
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if (range_id) |
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return pfn; |
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return pfn + vmem_altmap_offset(pgmap_altmap(pgmap)); |
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} |
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bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) |
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{ |
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int i; |
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for (i = 0; i < pgmap->nr_range; i++) { |
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struct range *range = &pgmap->ranges[i]; |
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if (pfn >= PHYS_PFN(range->start) && |
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pfn <= PHYS_PFN(range->end)) |
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return pfn >= pfn_first(pgmap, i); |
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} |
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return false; |
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} |
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static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id) |
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{ |
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const struct range *range = &pgmap->ranges[range_id]; |
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return (range->start + range_len(range)) >> 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, i) \ |
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for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); 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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* Undo the pgmap ref assignment for the internal case as the |
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* caller may re-enable the same pgmap. |
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*/ |
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if (pgmap->ref == &pgmap->internal_ref) |
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pgmap->ref = NULL; |
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} |
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static void pageunmap_range(struct dev_pagemap *pgmap, int range_id) |
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{ |
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struct range *range = &pgmap->ranges[range_id]; |
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struct page *first_page; |
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/* make sure to access a memmap that was actually initialized */ |
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first_page = pfn_to_page(pfn_first(pgmap, range_id)); |
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/* pages are dead and unused, undo the arch mapping */ |
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mem_hotplug_begin(); |
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remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(range->start), |
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PHYS_PFN(range_len(range))); |
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if (pgmap->type == MEMORY_DEVICE_PRIVATE) { |
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__remove_pages(PHYS_PFN(range->start), |
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PHYS_PFN(range_len(range)), NULL); |
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} else { |
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arch_remove_memory(range->start, range_len(range), |
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pgmap_altmap(pgmap)); |
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kasan_remove_zero_shadow(__va(range->start), range_len(range)); |
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} |
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mem_hotplug_done(); |
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untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range)); |
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pgmap_array_delete(range); |
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} |
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void memunmap_pages(struct dev_pagemap *pgmap) |
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{ |
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unsigned long pfn; |
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int i; |
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dev_pagemap_kill(pgmap); |
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for (i = 0; i < pgmap->nr_range; i++) |
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for_each_device_pfn(pfn, pgmap, i) |
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put_page(pfn_to_page(pfn)); |
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dev_pagemap_cleanup(pgmap); |
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for (i = 0; i < pgmap->nr_range; i++) |
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pageunmap_range(pgmap, i); |
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WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); |
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devmap_managed_enable_put(pgmap); |
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} |
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EXPORT_SYMBOL_GPL(memunmap_pages); |
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static void devm_memremap_pages_release(void *data) |
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{ |
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memunmap_pages(data); |
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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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static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, |
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int range_id, int nid) |
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{ |
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const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE; |
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struct range *range = &pgmap->ranges[range_id]; |
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struct dev_pagemap *conflict_pgmap; |
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int error, is_ram; |
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if (WARN_ONCE(pgmap_altmap(pgmap) && range_id > 0, |
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"altmap not supported for multiple ranges\n")) |
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return -EINVAL; |
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conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL); |
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if (conflict_pgmap) { |
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WARN(1, "Conflicting mapping in same section\n"); |
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put_dev_pagemap(conflict_pgmap); |
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return -ENOMEM; |
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} |
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conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL); |
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if (conflict_pgmap) { |
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WARN(1, "Conflicting mapping in same section\n"); |
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put_dev_pagemap(conflict_pgmap); |
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return -ENOMEM; |
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} |
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is_ram = region_intersects(range->start, range_len(range), |
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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, "attempted on %s region %#llx-%#llx\n", |
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is_ram == REGION_MIXED ? "mixed" : "ram", |
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range->start, range->end); |
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return -ENXIO; |
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} |
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error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(range->start), |
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PHYS_PFN(range->end), pgmap, GFP_KERNEL)); |
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if (error) |
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return error; |
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if (nid < 0) |
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nid = numa_mem_id(); |
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error = track_pfn_remap(NULL, ¶ms->pgprot, PHYS_PFN(range->start), 0, |
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range_len(range)); |
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if (error) |
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goto err_pfn_remap; |
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if (!mhp_range_allowed(range->start, range_len(range), !is_private)) { |
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error = -EINVAL; |
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goto err_pfn_remap; |
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} |
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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 (is_private) { |
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error = add_pages(nid, PHYS_PFN(range->start), |
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PHYS_PFN(range_len(range)), params); |
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} else { |
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error = kasan_add_zero_shadow(__va(range->start), range_len(range)); |
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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, range->start, range_len(range), |
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params); |
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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(range->start), |
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PHYS_PFN(range_len(range)), params->altmap, |
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MIGRATE_MOVABLE); |
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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(range->start), |
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PHYS_PFN(range_len(range)), pgmap); |
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percpu_ref_get_many(pgmap->ref, pfn_end(pgmap, range_id) |
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- pfn_first(pgmap, range_id)); |
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return 0; |
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err_add_memory: |
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kasan_remove_zero_shadow(__va(range->start), range_len(range)); |
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err_kasan: |
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untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range)); |
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err_pfn_remap: |
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pgmap_array_delete(range); |
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return error; |
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} |
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/* |
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* Not device managed version of dev_memremap_pages, undone by |
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* memunmap_pages(). Please use dev_memremap_pages if you have a struct |
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* device available. |
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*/ |
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void *memremap_pages(struct dev_pagemap *pgmap, int nid) |
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{ |
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struct mhp_params params = { |
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.altmap = pgmap_altmap(pgmap), |
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.pgprot = PAGE_KERNEL, |
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}; |
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const int nr_range = pgmap->nr_range; |
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int error, i; |
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if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) |
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return ERR_PTR(-EINVAL); |
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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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if (!pgmap->ops->page_free) { |
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WARN(1, "Missing page_free method\n"); |
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return ERR_PTR(-EINVAL); |
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} |
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if (!pgmap->owner) { |
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WARN(1, "Missing owner\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_GENERIC: |
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break; |
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case MEMORY_DEVICE_PCI_P2PDMA: |
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params.pgprot = pgprot_noncached(params.pgprot); |
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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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devmap_managed_enable_get(pgmap); |
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/* |
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* Clear the pgmap nr_range as it will be incremented for each |
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* successfully processed range. This communicates how many |
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* regions to unwind in the abort case. |
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*/ |
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pgmap->nr_range = 0; |
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error = 0; |
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for (i = 0; i < nr_range; i++) { |
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error = pagemap_range(pgmap, ¶ms, i, nid); |
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if (error) |
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break; |
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pgmap->nr_range++; |
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} |
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if (i < nr_range) { |
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memunmap_pages(pgmap); |
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pgmap->nr_range = nr_range; |
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return ERR_PTR(error); |
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} |
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return __va(pgmap->ranges[0].start); |
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} |
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EXPORT_SYMBOL_GPL(memremap_pages); |
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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/ range 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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int error; |
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void *ret; |
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ret = memremap_pages(pgmap, dev_to_node(dev)); |
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if (IS_ERR(ret)) |
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return ret; |
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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 ret; |
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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->range.start && phys <= pgmap->range.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 free_devmap_managed_page(struct page *page) |
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{ |
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/* notify page idle for dax */ |
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if (!is_device_private_page(page)) { |
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wake_up_var(&page->_refcount); |
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return; |
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} |
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__ClearPageWaiters(page); |
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mem_cgroup_uncharge(page); |
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|
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/* |
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* When a device_private page is freed, the page->mapping field |
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* may still contain a (stale) mapping value. For example, the |
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* lower bits of page->mapping may still identify the page as an |
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* anonymous page. Ultimately, this entire field is just stale |
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* and wrong, and it will cause errors if not cleared. One |
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* example is: |
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* |
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* migrate_vma_pages() |
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* migrate_vma_insert_page() |
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* page_add_new_anon_rmap() |
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* __page_set_anon_rmap() |
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* ...checks page->mapping, via PageAnon(page) call, |
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* and incorrectly concludes that the page is an |
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* anonymous page. Therefore, it incorrectly, |
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* silently fails to set up the new anon rmap. |
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* |
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* For other types of ZONE_DEVICE pages, migration is either |
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* handled differently or not done at all, so there is no need |
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* to clear page->mapping. |
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*/ |
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page->mapping = NULL; |
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page->pgmap->ops->page_free(page); |
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} |
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#endif /* CONFIG_DEV_PAGEMAP_OPS */
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