Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 870 insertions, 0 deletions

diff --git a/mm/internal.h b/mm/internal.h
new file mode 100644
index 000000000..d01130efc
--- /dev/null
+++ b/mm/internal.h
@@ -0,0 +1,870 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* internal.h: mm/ internal definitions
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+#ifndef __MM_INTERNAL_H
+#define __MM_INTERNAL_H
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/rmap.h>
+#include <linux/tracepoint-defs.h>
+
+struct folio_batch;
+
+/*
+ * The set of flags that only affect watermark checking and reclaim
+ * behaviour. This is used by the MM to obey the caller constraints
+ * about IO, FS and watermark checking while ignoring placement
+ * hints such as HIGHMEM usage.
+ */
+#define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\
+			__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NOFAIL|\
+			__GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\
+			__GFP_ATOMIC|__GFP_NOLOCKDEP)
+
+/* The GFP flags allowed during early boot */
+#define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
+
+/* Control allocation cpuset and node placement constraints */
+#define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
+
+/* Do not use these with a slab allocator */
+#define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
+
+/*
+ * Different from WARN_ON_ONCE(), no warning will be issued
+ * when we specify __GFP_NOWARN.
+ */
+#define WARN_ON_ONCE_GFP(cond, gfp)	({				\
+	static bool __section(".data.once") __warned;			\
+	int __ret_warn_once = !!(cond);					\
+									\
+	if (unlikely(!(gfp & __GFP_NOWARN) && __ret_warn_once && !__warned)) { \
+		__warned = true;					\
+		WARN_ON(1);						\
+	}								\
+	unlikely(__ret_warn_once);					\
+})
+
+void page_writeback_init(void);
+
+static inline void *folio_raw_mapping(struct folio *folio)
+{
+	unsigned long mapping = (unsigned long)folio->mapping;
+
+	return (void *)(mapping & ~PAGE_MAPPING_FLAGS);
+}
+
+void __acct_reclaim_writeback(pg_data_t *pgdat, struct folio *folio,
+						int nr_throttled);
+static inline void acct_reclaim_writeback(struct folio *folio)
+{
+	pg_data_t *pgdat = folio_pgdat(folio);
+	int nr_throttled = atomic_read(&pgdat->nr_writeback_throttled);
+
+	if (nr_throttled)
+		__acct_reclaim_writeback(pgdat, folio, nr_throttled);
+}
+
+static inline void wake_throttle_isolated(pg_data_t *pgdat)
+{
+	wait_queue_head_t *wqh;
+
+	wqh = &pgdat->reclaim_wait[VMSCAN_THROTTLE_ISOLATED];
+	if (waitqueue_active(wqh))
+		wake_up(wqh);
+}
+
+vm_fault_t do_swap_page(struct vm_fault *vmf);
+void folio_rotate_reclaimable(struct folio *folio);
+bool __folio_end_writeback(struct folio *folio);
+void deactivate_file_folio(struct folio *folio);
+void folio_activate(struct folio *folio);
+
+void free_pgtables(struct mmu_gather *tlb, struct maple_tree *mt,
+		   struct vm_area_struct *start_vma, unsigned long floor,
+		   unsigned long ceiling);
+void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte);
+
+struct zap_details;
+void unmap_page_range(struct mmu_gather *tlb,
+			     struct vm_area_struct *vma,
+			     unsigned long addr, unsigned long end,
+			     struct zap_details *details);
+
+void page_cache_ra_order(struct readahead_control *, struct file_ra_state *,
+		unsigned int order);
+void force_page_cache_ra(struct readahead_control *, unsigned long nr);
+static inline void force_page_cache_readahead(struct address_space *mapping,
+		struct file *file, pgoff_t index, unsigned long nr_to_read)
+{
+	DEFINE_READAHEAD(ractl, file, &file->f_ra, mapping, index);
+	force_page_cache_ra(&ractl, nr_to_read);
+}
+
+unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,
+		pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices);
+unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
+		pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices);
+void filemap_free_folio(struct address_space *mapping, struct folio *folio);
+int truncate_inode_folio(struct address_space *mapping, struct folio *folio);
+bool truncate_inode_partial_folio(struct folio *folio, loff_t start,
+		loff_t end);
+long invalidate_inode_page(struct page *page);
+unsigned long invalidate_mapping_pagevec(struct address_space *mapping,
+		pgoff_t start, pgoff_t end, unsigned long *nr_pagevec);
+
+/**
+ * folio_evictable - Test whether a folio is evictable.
+ * @folio: The folio to test.
+ *
+ * Test whether @folio is evictable -- i.e., should be placed on
+ * active/inactive lists vs unevictable list.
+ *
+ * Reasons folio might not be evictable:
+ * 1. folio's mapping marked unevictable
+ * 2. One of the pages in the folio is part of an mlocked VMA
+ */
+static inline bool folio_evictable(struct folio *folio)
+{
+	bool ret;
+
+	/* Prevent address_space of inode and swap cache from being freed */
+	rcu_read_lock();
+	ret = !mapping_unevictable(folio_mapping(folio)) &&
+			!folio_test_mlocked(folio);
+	rcu_read_unlock();
+	return ret;
+}
+
+static inline bool page_evictable(struct page *page)
+{
+	bool ret;
+
+	/* Prevent address_space of inode and swap cache from being freed */
+	rcu_read_lock();
+	ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
+	rcu_read_unlock();
+	return ret;
+}
+
+/*
+ * Turn a non-refcounted page (->_refcount == 0) into refcounted with
+ * a count of one.
+ */
+static inline void set_page_refcounted(struct page *page)
+{
+	VM_BUG_ON_PAGE(PageTail(page), page);
+	VM_BUG_ON_PAGE(page_ref_count(page), page);
+	set_page_count(page, 1);
+}
+
+/*
+ * Return true if a folio needs ->release_folio() calling upon it.
+ */
+static inline bool folio_needs_release(struct folio *folio)
+{
+	struct address_space *mapping = folio_mapping(folio);
+
+	return folio_has_private(folio) ||
+		(mapping && mapping_release_always(mapping));
+}
+
+extern unsigned long highest_memmap_pfn;
+
+/*
+ * Maximum number of reclaim retries without progress before the OOM
+ * killer is consider the only way forward.
+ */
+#define MAX_RECLAIM_RETRIES 16
+
+/*
+ * in mm/early_ioremap.c
+ */
+pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,
+					unsigned long size, pgprot_t prot);
+
+/*
+ * in mm/vmscan.c:
+ */
+int isolate_lru_page(struct page *page);
+int folio_isolate_lru(struct folio *folio);
+void putback_lru_page(struct page *page);
+void folio_putback_lru(struct folio *folio);
+extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason);
+
+/*
+ * in mm/rmap.c:
+ */
+pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
+
+/*
+ * in mm/page_alloc.c
+ */
+
+/*
+ * Structure for holding the mostly immutable allocation parameters passed
+ * between functions involved in allocations, including the alloc_pages*
+ * family of functions.
+ *
+ * nodemask, migratetype and highest_zoneidx are initialized only once in
+ * __alloc_pages() and then never change.
+ *
+ * zonelist, preferred_zone and highest_zoneidx are set first in
+ * __alloc_pages() for the fast path, and might be later changed
+ * in __alloc_pages_slowpath(). All other functions pass the whole structure
+ * by a const pointer.
+ */
+struct alloc_context {
+	struct zonelist *zonelist;
+	nodemask_t *nodemask;
+	struct zoneref *preferred_zoneref;
+	int migratetype;
+
+	/*
+	 * highest_zoneidx represents highest usable zone index of
+	 * the allocation request. Due to the nature of the zone,
+	 * memory on lower zone than the highest_zoneidx will be
+	 * protected by lowmem_reserve[highest_zoneidx].
+	 *
+	 * highest_zoneidx is also used by reclaim/compaction to limit
+	 * the target zone since higher zone than this index cannot be
+	 * usable for this allocation request.
+	 */
+	enum zone_type highest_zoneidx;
+	bool spread_dirty_pages;
+};
+
+/*
+ * This function returns the order of a free page in the buddy system. In
+ * general, page_zone(page)->lock must be held by the caller to prevent the
+ * page from being allocated in parallel and returning garbage as the order.
+ * If a caller does not hold page_zone(page)->lock, it must guarantee that the
+ * page cannot be allocated or merged in parallel. Alternatively, it must
+ * handle invalid values gracefully, and use buddy_order_unsafe() below.
+ */
+static inline unsigned int buddy_order(struct page *page)
+{
+	/* PageBuddy() must be checked by the caller */
+	return page_private(page);
+}
+
+/*
+ * Like buddy_order(), but for callers who cannot afford to hold the zone lock.
+ * PageBuddy() should be checked first by the caller to minimize race window,
+ * and invalid values must be handled gracefully.
+ *
+ * READ_ONCE is used so that if the caller assigns the result into a local
+ * variable and e.g. tests it for valid range before using, the compiler cannot
+ * decide to remove the variable and inline the page_private(page) multiple
+ * times, potentially observing different values in the tests and the actual
+ * use of the result.
+ */
+#define buddy_order_unsafe(page)	READ_ONCE(page_private(page))
+
+/*
+ * This function checks whether a page is free && is the buddy
+ * we can coalesce a page and its buddy if
+ * (a) the buddy is not in a hole (check before calling!) &&
+ * (b) the buddy is in the buddy system &&
+ * (c) a page and its buddy have the same order &&
+ * (d) a page and its buddy are in the same zone.
+ *
+ * For recording whether a page is in the buddy system, we set PageBuddy.
+ * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
+ *
+ * For recording page's order, we use page_private(page).
+ */
+static inline bool page_is_buddy(struct page *page, struct page *buddy,
+				 unsigned int order)
+{
+	if (!page_is_guard(buddy) && !PageBuddy(buddy))
+		return false;
+
+	if (buddy_order(buddy) != order)
+		return false;
+
+	/*
+	 * zone check is done late to avoid uselessly calculating
+	 * zone/node ids for pages that could never merge.
+	 */
+	if (page_zone_id(page) != page_zone_id(buddy))
+		return false;
+
+	VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
+
+	return true;
+}
+
+/*
+ * Locate the struct page for both the matching buddy in our
+ * pair (buddy1) and the combined O(n+1) page they form (page).
+ *
+ * 1) Any buddy B1 will have an order O twin B2 which satisfies
+ * the following equation:
+ *     B2 = B1 ^ (1 << O)
+ * For example, if the starting buddy (buddy2) is #8 its order
+ * 1 buddy is #10:
+ *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
+ *
+ * 2) Any buddy B will have an order O+1 parent P which
+ * satisfies the following equation:
+ *     P = B & ~(1 << O)
+ *
+ * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
+ */
+static inline unsigned long
+__find_buddy_pfn(unsigned long page_pfn, unsigned int order)
+{
+	return page_pfn ^ (1 << order);
+}
+
+/*
+ * Find the buddy of @page and validate it.
+ * @page: The input page
+ * @pfn: The pfn of the page, it saves a call to page_to_pfn() when the
+ *       function is used in the performance-critical __free_one_page().
+ * @order: The order of the page
+ * @buddy_pfn: The output pointer to the buddy pfn, it also saves a call to
+ *             page_to_pfn().
+ *
+ * The found buddy can be a non PageBuddy, out of @page's zone, or its order is
+ * not the same as @page. The validation is necessary before use it.
+ *
+ * Return: the found buddy page or NULL if not found.
+ */
+static inline struct page *find_buddy_page_pfn(struct page *page,
+			unsigned long pfn, unsigned int order, unsigned long *buddy_pfn)
+{
+	unsigned long __buddy_pfn = __find_buddy_pfn(pfn, order);
+	struct page *buddy;
+
+	buddy = page + (__buddy_pfn - pfn);
+	if (buddy_pfn)
+		*buddy_pfn = __buddy_pfn;
+
+	if (page_is_buddy(page, buddy, order))
+		return buddy;
+	return NULL;
+}
+
+extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
+				unsigned long end_pfn, struct zone *zone);
+
+static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
+				unsigned long end_pfn, struct zone *zone)
+{
+	if (zone->contiguous)
+		return pfn_to_page(start_pfn);
+
+	return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
+}
+
+extern int __isolate_free_page(struct page *page, unsigned int order);
+extern void __putback_isolated_page(struct page *page, unsigned int order,
+				    int mt);
+extern void memblock_free_pages(struct page *page, unsigned long pfn,
+					unsigned int order);
+extern void __free_pages_core(struct page *page, unsigned int order);
+extern void prep_compound_page(struct page *page, unsigned int order);
+extern void post_alloc_hook(struct page *page, unsigned int order,
+					gfp_t gfp_flags);
+extern int user_min_free_kbytes;
+
+extern void free_unref_page(struct page *page, unsigned int order);
+extern void free_unref_page_list(struct list_head *list);
+
+extern void zone_pcp_reset(struct zone *zone);
+extern void zone_pcp_disable(struct zone *zone);
+extern void zone_pcp_enable(struct zone *zone);
+
+extern void *memmap_alloc(phys_addr_t size, phys_addr_t align,
+			  phys_addr_t min_addr,
+			  int nid, bool exact_nid);
+
+int split_free_page(struct page *free_page,
+			unsigned int order, unsigned long split_pfn_offset);
+
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+
+/*
+ * in mm/compaction.c
+ */
+/*
+ * compact_control is used to track pages being migrated and the free pages
+ * they are being migrated to during memory compaction. The free_pfn starts
+ * at the end of a zone and migrate_pfn begins at the start. Movable pages
+ * are moved to the end of a zone during a compaction run and the run
+ * completes when free_pfn <= migrate_pfn
+ */
+struct compact_control {
+	struct list_head freepages;	/* List of free pages to migrate to */
+	struct list_head migratepages;	/* List of pages being migrated */
+	unsigned int nr_freepages;	/* Number of isolated free pages */
+	unsigned int nr_migratepages;	/* Number of pages to migrate */
+	unsigned long free_pfn;		/* isolate_freepages search base */
+	/*
+	 * Acts as an in/out parameter to page isolation for migration.
+	 * isolate_migratepages uses it as a search base.
+	 * isolate_migratepages_block will update the value to the next pfn
+	 * after the last isolated one.
+	 */
+	unsigned long migrate_pfn;
+	unsigned long fast_start_pfn;	/* a pfn to start linear scan from */
+	struct zone *zone;
+	unsigned long total_migrate_scanned;
+	unsigned long total_free_scanned;
+	unsigned short fast_search_fail;/* failures to use free list searches */
+	short search_order;		/* order to start a fast search at */
+	const gfp_t gfp_mask;		/* gfp mask of a direct compactor */
+	int order;			/* order a direct compactor needs */
+	int migratetype;		/* migratetype of direct compactor */
+	const unsigned int alloc_flags;	/* alloc flags of a direct compactor */
+	const int highest_zoneidx;	/* zone index of a direct compactor */
+	enum migrate_mode mode;		/* Async or sync migration mode */
+	bool ignore_skip_hint;		/* Scan blocks even if marked skip */
+	bool no_set_skip_hint;		/* Don't mark blocks for skipping */
+	bool ignore_block_suitable;	/* Scan blocks considered unsuitable */
+	bool direct_compaction;		/* False from kcompactd or /proc/... */
+	bool proactive_compaction;	/* kcompactd proactive compaction */
+	bool whole_zone;		/* Whole zone should/has been scanned */
+	bool contended;			/* Signal lock contention */
+	bool rescan;			/* Rescanning the same pageblock */
+	bool alloc_contig;		/* alloc_contig_range allocation */
+};
+
+/*
+ * Used in direct compaction when a page should be taken from the freelists
+ * immediately when one is created during the free path.
+ */
+struct capture_control {
+	struct compact_control *cc;
+	struct page *page;
+};
+
+unsigned long
+isolate_freepages_range(struct compact_control *cc,
+			unsigned long start_pfn, unsigned long end_pfn);
+int
+isolate_migratepages_range(struct compact_control *cc,
+			   unsigned long low_pfn, unsigned long end_pfn);
+
+int __alloc_contig_migrate_range(struct compact_control *cc,
+					unsigned long start, unsigned long end);
+#endif
+int find_suitable_fallback(struct free_area *area, unsigned int order,
+			int migratetype, bool only_stealable, bool *can_steal);
+
+/*
+ * These three helpers classifies VMAs for virtual memory accounting.
+ */
+
+/*
+ * Executable code area - executable, not writable, not stack
+ */
+static inline bool is_exec_mapping(vm_flags_t flags)
+{
+	return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
+}
+
+/*
+ * Stack area - automatically grows in one direction
+ *
+ * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
+ * do_mmap() forbids all other combinations.
+ */
+static inline bool is_stack_mapping(vm_flags_t flags)
+{
+	return (flags & VM_STACK) == VM_STACK;
+}
+
+/*
+ * Data area - private, writable, not stack
+ */
+static inline bool is_data_mapping(vm_flags_t flags)
+{
+	return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
+}
+
+/* mm/util.c */
+struct anon_vma *folio_anon_vma(struct folio *folio);
+
+#ifdef CONFIG_MMU
+void unmap_mapping_folio(struct folio *folio);
+extern long populate_vma_page_range(struct vm_area_struct *vma,
+		unsigned long start, unsigned long end, int *locked);
+extern long faultin_vma_page_range(struct vm_area_struct *vma,
+				   unsigned long start, unsigned long end,
+				   bool write, int *locked);
+extern int mlock_future_check(struct mm_struct *mm, unsigned long flags,
+			      unsigned long len);
+/*
+ * mlock_vma_page() and munlock_vma_page():
+ * should be called with vma's mmap_lock held for read or write,
+ * under page table lock for the pte/pmd being added or removed.
+ *
+ * mlock is usually called at the end of page_add_*_rmap(),
+ * munlock at the end of page_remove_rmap(); but new anon
+ * pages are managed by lru_cache_add_inactive_or_unevictable()
+ * calling mlock_new_page().
+ *
+ * @compound is used to include pmd mappings of THPs, but filter out
+ * pte mappings of THPs, which cannot be consistently counted: a pte
+ * mapping of the THP head cannot be distinguished by the page alone.
+ */
+void mlock_folio(struct folio *folio);
+static inline void mlock_vma_folio(struct folio *folio,
+			struct vm_area_struct *vma, bool compound)
+{
+	/*
+	 * The VM_SPECIAL check here serves two purposes.
+	 * 1) VM_IO check prevents migration from double-counting during mlock.
+	 * 2) Although mmap_region() and mlock_fixup() take care that VM_LOCKED
+	 *    is never left set on a VM_SPECIAL vma, there is an interval while
+	 *    file->f_op->mmap() is using vm_insert_page(s), when VM_LOCKED may
+	 *    still be set while VM_SPECIAL bits are added: so ignore it then.
+	 */
+	if (unlikely((vma->vm_flags & (VM_LOCKED|VM_SPECIAL)) == VM_LOCKED) &&
+	    (compound || !folio_test_large(folio)))
+		mlock_folio(folio);
+}
+
+static inline void mlock_vma_page(struct page *page,
+			struct vm_area_struct *vma, bool compound)
+{
+	mlock_vma_folio(page_folio(page), vma, compound);
+}
+
+void munlock_page(struct page *page);
+static inline void munlock_vma_page(struct page *page,
+			struct vm_area_struct *vma, bool compound)
+{
+	if (unlikely(vma->vm_flags & VM_LOCKED) &&
+	    (compound || !PageTransCompound(page)))
+		munlock_page(page);
+}
+void mlock_new_page(struct page *page);
+bool need_mlock_page_drain(int cpu);
+void mlock_page_drain_local(void);
+void mlock_page_drain_remote(int cpu);
+
+extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
+
+/*
+ * Return the start of user virtual address at the specific offset within
+ * a vma.
+ */
+static inline unsigned long
+vma_pgoff_address(pgoff_t pgoff, unsigned long nr_pages,
+		  struct vm_area_struct *vma)
+{
+	unsigned long address;
+
+	if (pgoff >= vma->vm_pgoff) {
+		address = vma->vm_start +
+			((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+		/* Check for address beyond vma (or wrapped through 0?) */
+		if (address < vma->vm_start || address >= vma->vm_end)
+			address = -EFAULT;
+	} else if (pgoff + nr_pages - 1 >= vma->vm_pgoff) {
+		/* Test above avoids possibility of wrap to 0 on 32-bit */
+		address = vma->vm_start;
+	} else {
+		address = -EFAULT;
+	}
+	return address;
+}
+
+/*
+ * Return the start of user virtual address of a page within a vma.
+ * Returns -EFAULT if all of the page is outside the range of vma.
+ * If page is a compound head, the entire compound page is considered.
+ */
+static inline unsigned long
+vma_address(struct page *page, struct vm_area_struct *vma)
+{
+	VM_BUG_ON_PAGE(PageKsm(page), page);	/* KSM page->index unusable */
+	return vma_pgoff_address(page_to_pgoff(page), compound_nr(page), vma);
+}
+
+/*
+ * Then at what user virtual address will none of the range be found in vma?
+ * Assumes that vma_address() already returned a good starting address.
+ */
+static inline unsigned long vma_address_end(struct page_vma_mapped_walk *pvmw)
+{
+	struct vm_area_struct *vma = pvmw->vma;
+	pgoff_t pgoff;
+	unsigned long address;
+
+	/* Common case, plus ->pgoff is invalid for KSM */
+	if (pvmw->nr_pages == 1)
+		return pvmw->address + PAGE_SIZE;
+
+	pgoff = pvmw->pgoff + pvmw->nr_pages;
+	address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+	/* Check for address beyond vma (or wrapped through 0?) */
+	if (address < vma->vm_start || address > vma->vm_end)
+		address = vma->vm_end;
+	return address;
+}
+
+static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
+						    struct file *fpin)
+{
+	int flags = vmf->flags;
+
+	if (fpin)
+		return fpin;
+
+	/*
+	 * FAULT_FLAG_RETRY_NOWAIT means we don't want to wait on page locks or
+	 * anything, so we only pin the file and drop the mmap_lock if only
+	 * FAULT_FLAG_ALLOW_RETRY is set, while this is the first attempt.
+	 */
+	if (fault_flag_allow_retry_first(flags) &&
+	    !(flags & FAULT_FLAG_RETRY_NOWAIT)) {
+		fpin = get_file(vmf->vma->vm_file);
+		mmap_read_unlock(vmf->vma->vm_mm);
+	}
+	return fpin;
+}
+#else /* !CONFIG_MMU */
+static inline void unmap_mapping_folio(struct folio *folio) { }
+static inline void mlock_vma_page(struct page *page,
+			struct vm_area_struct *vma, bool compound) { }
+static inline void munlock_vma_page(struct page *page,
+			struct vm_area_struct *vma, bool compound) { }
+static inline void mlock_new_page(struct page *page) { }
+static inline bool need_mlock_page_drain(int cpu) { return false; }
+static inline void mlock_page_drain_local(void) { }
+static inline void mlock_page_drain_remote(int cpu) { }
+static inline void vunmap_range_noflush(unsigned long start, unsigned long end)
+{
+}
+#endif /* !CONFIG_MMU */
+
+/* Memory initialisation debug and verification */
+enum mminit_level {
+	MMINIT_WARNING,
+	MMINIT_VERIFY,
+	MMINIT_TRACE
+};
+
+#ifdef CONFIG_DEBUG_MEMORY_INIT
+
+extern int mminit_loglevel;
+
+#define mminit_dprintk(level, prefix, fmt, arg...) \
+do { \
+	if (level < mminit_loglevel) { \
+		if (level <= MMINIT_WARNING) \
+			pr_warn("mminit::" prefix " " fmt, ##arg);	\
+		else \
+			printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
+	} \
+} while (0)
+
+extern void mminit_verify_pageflags_layout(void);
+extern void mminit_verify_zonelist(void);
+#else
+
+static inline void mminit_dprintk(enum mminit_level level,
+				const char *prefix, const char *fmt, ...)
+{
+}
+
+static inline void mminit_verify_pageflags_layout(void)
+{
+}
+
+static inline void mminit_verify_zonelist(void)
+{
+}
+#endif /* CONFIG_DEBUG_MEMORY_INIT */
+
+#define NODE_RECLAIM_NOSCAN	-2
+#define NODE_RECLAIM_FULL	-1
+#define NODE_RECLAIM_SOME	0
+#define NODE_RECLAIM_SUCCESS	1
+
+#ifdef CONFIG_NUMA
+extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
+extern int find_next_best_node(int node, nodemask_t *used_node_mask);
+#else
+static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
+				unsigned int order)
+{
+	return NODE_RECLAIM_NOSCAN;
+}
+static inline int find_next_best_node(int node, nodemask_t *used_node_mask)
+{
+	return NUMA_NO_NODE;
+}
+#endif
+
+/*
+ * mm/memory-failure.c
+ */
+extern int hwpoison_filter(struct page *p);
+
+extern u32 hwpoison_filter_dev_major;
+extern u32 hwpoison_filter_dev_minor;
+extern u64 hwpoison_filter_flags_mask;
+extern u64 hwpoison_filter_flags_value;
+extern u64 hwpoison_filter_memcg;
+extern u32 hwpoison_filter_enable;
+
+#ifdef CONFIG_MEMORY_FAILURE
+void clear_hwpoisoned_pages(struct page *memmap, int nr_pages);
+#else
+static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
+{
+}
+#endif
+
+extern unsigned long  __must_check vm_mmap_pgoff(struct file *, unsigned long,
+        unsigned long, unsigned long,
+        unsigned long, unsigned long);
+
+extern void set_pageblock_order(void);
+unsigned int reclaim_clean_pages_from_list(struct zone *zone,
+					    struct list_head *page_list);
+/* The ALLOC_WMARK bits are used as an index to zone->watermark */
+#define ALLOC_WMARK_MIN		WMARK_MIN
+#define ALLOC_WMARK_LOW		WMARK_LOW
+#define ALLOC_WMARK_HIGH	WMARK_HIGH
+#define ALLOC_NO_WATERMARKS	0x04 /* don't check watermarks at all */
+
+/* Mask to get the watermark bits */
+#define ALLOC_WMARK_MASK	(ALLOC_NO_WATERMARKS-1)
+
+/*
+ * Only MMU archs have async oom victim reclaim - aka oom_reaper so we
+ * cannot assume a reduced access to memory reserves is sufficient for
+ * !MMU
+ */
+#ifdef CONFIG_MMU
+#define ALLOC_OOM		0x08
+#else
+#define ALLOC_OOM		ALLOC_NO_WATERMARKS
+#endif
+
+#define ALLOC_HARDER		 0x10 /* try to alloc harder */
+#define ALLOC_HIGH		 0x20 /* __GFP_HIGH set */
+#define ALLOC_CPUSET		 0x40 /* check for correct cpuset */
+#define ALLOC_CMA		 0x80 /* allow allocations from CMA areas */
+#ifdef CONFIG_ZONE_DMA32
+#define ALLOC_NOFRAGMENT	0x100 /* avoid mixing pageblock types */
+#else
+#define ALLOC_NOFRAGMENT	  0x0
+#endif
+#define ALLOC_KSWAPD		0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
+
+enum ttu_flags;
+struct tlbflush_unmap_batch;
+
+
+/*
+ * only for MM internal work items which do not depend on
+ * any allocations or locks which might depend on allocations
+ */
+extern struct workqueue_struct *mm_percpu_wq;
+
+#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
+void try_to_unmap_flush(void);
+void try_to_unmap_flush_dirty(void);
+void flush_tlb_batched_pending(struct mm_struct *mm);
+#else
+static inline void try_to_unmap_flush(void)
+{
+}
+static inline void try_to_unmap_flush_dirty(void)
+{
+}
+static inline void flush_tlb_batched_pending(struct mm_struct *mm)
+{
+}
+#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
+
+extern const struct trace_print_flags pageflag_names[];
+extern const struct trace_print_flags vmaflag_names[];
+extern const struct trace_print_flags gfpflag_names[];
+
+static inline bool is_migrate_highatomic(enum migratetype migratetype)
+{
+	return migratetype == MIGRATE_HIGHATOMIC;
+}
+
+static inline bool is_migrate_highatomic_page(struct page *page)
+{
+	return get_pageblock_migratetype(page) == MIGRATE_HIGHATOMIC;
+}
+
+void setup_zone_pageset(struct zone *zone);
+
+struct migration_target_control {
+	int nid;		/* preferred node id */
+	nodemask_t *nmask;
+	gfp_t gfp_mask;
+};
+
+/*
+ * mm/vmalloc.c
+ */
+#ifdef CONFIG_MMU
+int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
+                pgprot_t prot, struct page **pages, unsigned int page_shift);
+#else
+static inline
+int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
+                pgprot_t prot, struct page **pages, unsigned int page_shift)
+{
+	return -EINVAL;
+}
+#endif
+
+int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
+			       pgprot_t prot, struct page **pages,
+			       unsigned int page_shift);
+
+void vunmap_range_noflush(unsigned long start, unsigned long end);
+
+void __vunmap_range_noflush(unsigned long start, unsigned long end);
+
+int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
+		      unsigned long addr, int page_nid, int *flags);
+
+void free_zone_device_page(struct page *page);
+int migrate_device_coherent_page(struct page *page);
+
+/*
+ * mm/gup.c
+ */
+struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags);
+
+extern bool mirrored_kernelcore;
+
+static inline bool vma_soft_dirty_enabled(struct vm_area_struct *vma)
+{
+	/*
+	 * NOTE: we must check this before VM_SOFTDIRTY on soft-dirty
+	 * enablements, because when without soft-dirty being compiled in,
+	 * VM_SOFTDIRTY is defined as 0x0, then !(vm_flags & VM_SOFTDIRTY)
+	 * will be constantly true.
+	 */
+	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
+		return false;
+
+	/*
+	 * Soft-dirty is kind of special: its tracking is enabled when the
+	 * vma flags not set.
+	 */
+	return !(vma->vm_flags & VM_SOFTDIRTY);
+}
+
+#endif	/* __MM_INTERNAL_H */