1 files changed, 171 insertions, 134 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 0201f50d8307..b5453b86ec4b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -112,8 +112,10 @@ static bool vmf_pte_changed(struct vm_fault *vmf);
  * Return true if the original pte was a uffd-wp pte marker (so the pte was
  * wr-protected).
  */
-static bool vmf_orig_pte_uffd_wp(struct vm_fault *vmf)
+static __always_inline bool vmf_orig_pte_uffd_wp(struct vm_fault *vmf)
 {
+	if (!userfaultfd_wp(vmf->vma))
+		return false;
 	if (!(vmf->flags & FAULT_FLAG_ORIG_PTE_VALID))
 		return false;
 
@@ -989,7 +991,7 @@ copy_present_ptes(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma
 			flags |= FPB_IGNORE_SOFT_DIRTY;
 
 		nr = folio_pte_batch(folio, addr, src_pte, pte, max_nr, flags,
-				     &any_writable);
+				     &any_writable, NULL, NULL);
 		folio_ref_add(folio, nr);
 		if (folio_test_anon(folio)) {
 			if (unlikely(folio_try_dup_anon_rmap_ptes(folio, page,
@@ -1502,10 +1504,15 @@ static __always_inline void zap_present_folio_ptes(struct mmu_gather *tlb,
 	if (!delay_rmap) {
 		folio_remove_rmap_ptes(folio, page, nr, vma);
 
-		/* Only sanity-check the first page in a batch. */
-		if (unlikely(page_mapcount(page) < 0))
+		if (unlikely(folio_mapcount(folio) < 0))
 			print_bad_pte(vma, addr, ptent, page);
 	}
+
+	if (want_init_mlocked_on_free() && folio_test_mlocked(folio) &&
+	    !delay_rmap && folio_test_anon(folio)) {
+		kernel_init_pages(page, folio_nr_pages(folio));
+	}
+
 	if (unlikely(__tlb_remove_folio_pages(tlb, page, nr, delay_rmap))) {
 		*force_flush = true;
 		*force_break = true;
@@ -1553,7 +1560,7 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
 	 */
 	if (unlikely(folio_test_large(folio) && max_nr != 1)) {
 		nr = folio_pte_batch(folio, addr, pte, ptent, max_nr, fpb_flags,
-				     NULL);
+				     NULL, NULL, NULL);
 
 		zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, nr,
 				       addr, details, rss, force_flush,
@@ -1631,12 +1638,13 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 				folio_remove_rmap_pte(folio, page, vma);
 			folio_put(folio);
 		} else if (!non_swap_entry(entry)) {
-			/* Genuine swap entry, hence a private anon page */
+			max_nr = (end - addr) / PAGE_SIZE;
+			nr = swap_pte_batch(pte, max_nr, ptent);
+			/* Genuine swap entries, hence a private anon pages */
 			if (!should_zap_cows(details))
 				continue;
-			rss[MM_SWAPENTS]--;
-			if (unlikely(!free_swap_and_cache(entry)))
-				print_bad_pte(vma, addr, ptent, NULL);
+			rss[MM_SWAPENTS] -= nr;
+			free_swap_and_cache_nr(entry, nr);
 		} else if (is_migration_entry(entry)) {
 			folio = pfn_swap_entry_folio(entry);
 			if (!should_zap_folio(details, folio))
@@ -1659,8 +1667,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 			pr_alert("unrecognized swap entry 0x%lx\n", entry.val);
 			WARN_ON_ONCE(1);
 		}
-		pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
-		zap_install_uffd_wp_if_needed(vma, addr, pte, 1, details, ptent);
+		clear_not_present_full_ptes(mm, addr, pte, nr, tlb->fullmm);
+		zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details, ptent);
 	} while (pte += nr, addr += PAGE_SIZE * nr, addr != end);
 
 	add_mm_rss_vec(mm, rss);
@@ -2765,7 +2773,7 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
 	unsigned long next;
 	int err = 0;
 
-	BUG_ON(pud_huge(*pud));
+	BUG_ON(pud_leaf(*pud));
 
 	if (create) {
 		pmd = pmd_alloc_track(mm, pud, addr, mask);
@@ -3206,19 +3214,39 @@ static inline vm_fault_t vmf_can_call_fault(const struct vm_fault *vmf)
 	return VM_FAULT_RETRY;
 }
 
+/**
+ * vmf_anon_prepare - Prepare to handle an anonymous fault.
+ * @vmf: The vm_fault descriptor passed from the fault handler.
+ *
+ * When preparing to insert an anonymous page into a VMA from a
+ * fault handler, call this function rather than anon_vma_prepare().
+ * If this vma does not already have an associated anon_vma and we are
+ * only protected by the per-VMA lock, the caller must retry with the
+ * mmap_lock held.  __anon_vma_prepare() will look at adjacent VMAs to
+ * determine if this VMA can share its anon_vma, and that's not safe to
+ * do with only the per-VMA lock held for this VMA.
+ *
+ * Return: 0 if fault handling can proceed.  Any other value should be
+ * returned to the caller.
+ */
 vm_fault_t vmf_anon_prepare(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
+	vm_fault_t ret = 0;
 
 	if (likely(vma->anon_vma))
 		return 0;
 	if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
-		vma_end_read(vma);
-		return VM_FAULT_RETRY;
+		if (!mmap_read_trylock(vma->vm_mm)) {
+			vma_end_read(vma);
+			return VM_FAULT_RETRY;
+		}
 	}
 	if (__anon_vma_prepare(vma))
-		return VM_FAULT_OOM;
-	return 0;
+		ret = VM_FAULT_OOM;
+	if (vmf->flags & FAULT_FLAG_VMA_LOCK)
+		mmap_read_unlock(vma->vm_mm);
+	return ret;
 }
 
 /*
@@ -4185,7 +4213,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 	 * when reading from swap. This metadata may be indexed by swap entry
 	 * so this must be called before swap_free().
 	 */
-	arch_swap_restore(entry, folio);
+	arch_swap_restore(folio_swap(entry, folio), folio);
 
 	/*
 	 * Remove the swap entry and conditionally try to free up the swapcache.
@@ -4321,8 +4349,8 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
 	 * for this vma. Then filter out the orders that can't be allocated over
 	 * the faulting address and still be fully contained in the vma.
 	 */
-	orders = thp_vma_allowable_orders(vma, vma->vm_flags, false, true, true,
-					  BIT(PMD_ORDER) - 1);
+	orders = thp_vma_allowable_orders(vma, vma->vm_flags,
+			TVA_IN_PF | TVA_ENFORCE_SYSFS, BIT(PMD_ORDER) - 1);
 	orders = thp_vma_suitable_orders(vma, vmf->address, orders);
 
 	if (!orders)
@@ -4347,6 +4375,9 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
 
 	pte_unmap(pte);
 
+	if (!orders)
+		goto fallback;
+
 	/* Try allocating the highest of the remaining orders. */
 	gfp = vma_thp_gfp_mask(vma);
 	while (orders) {
@@ -4354,6 +4385,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
 		folio = vma_alloc_folio(gfp, order, vma, addr, true);
 		if (folio) {
 			if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
+				count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
 				folio_put(folio);
 				goto next;
 			}
@@ -4362,6 +4394,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
 			return folio;
 		}
 next:
+		count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
 		order = next_order(&orders, order);
 	}
 
@@ -4377,7 +4410,6 @@ fallback:
  */
 static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 {
-	bool uffd_wp = vmf_orig_pte_uffd_wp(vmf);
 	struct vm_area_struct *vma = vmf->vma;
 	unsigned long addr = vmf->address;
 	struct folio *folio;
@@ -4422,8 +4454,9 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 	}
 
 	/* Allocate our own private page. */
-	if (unlikely(anon_vma_prepare(vma)))
-		goto oom;
+	ret = vmf_anon_prepare(vmf);
+	if (ret)
+		return ret;
 	/* Returns NULL on OOM or ERR_PTR(-EAGAIN) if we must retry the fault */
 	folio = alloc_anon_folio(vmf);
 	if (IS_ERR(folio))
@@ -4471,10 +4504,13 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 
 	folio_ref_add(folio, nr_pages - 1);
 	add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_FAULT_ALLOC);
+#endif
 	folio_add_new_anon_rmap(folio, vma, addr);
 	folio_add_lru_vma(folio, vma);
 setpte:
-	if (uffd_wp)
+	if (vmf_orig_pte_uffd_wp(vmf))
 		entry = pte_mkuffd_wp(entry);
 	set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr_pages);
 
@@ -4649,7 +4685,6 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
 		struct page *page, unsigned int nr, unsigned long addr)
 {
 	struct vm_area_struct *vma = vmf->vma;
-	bool uffd_wp = vmf_orig_pte_uffd_wp(vmf);
 	bool write = vmf->flags & FAULT_FLAG_WRITE;
 	bool prefault = in_range(vmf->address, addr, nr * PAGE_SIZE);
 	pte_t entry;
@@ -4664,16 +4699,14 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
 
 	if (write)
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-	if (unlikely(uffd_wp))
+	if (unlikely(vmf_orig_pte_uffd_wp(vmf)))
 		entry = pte_mkuffd_wp(entry);
 	/* copy-on-write page */
 	if (write && !(vma->vm_flags & VM_SHARED)) {
-		add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr);
 		VM_BUG_ON_FOLIO(nr != 1, folio);
 		folio_add_new_anon_rmap(folio, vma, addr);
 		folio_add_lru_vma(folio, vma);
 	} else {
-		add_mm_counter(vma->vm_mm, mm_counter_file(folio), nr);
 		folio_add_file_rmap_ptes(folio, page, nr, vma);
 	}
 	set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr);
@@ -4710,9 +4743,11 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
 	struct vm_area_struct *vma = vmf->vma;
 	struct page *page;
 	vm_fault_t ret;
+	bool is_cow = (vmf->flags & FAULT_FLAG_WRITE) &&
+		      !(vma->vm_flags & VM_SHARED);
 
 	/* Did we COW the page? */
-	if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
+	if (is_cow)
 		page = vmf->cow_page;
 	else
 		page = vmf->page;
@@ -4748,8 +4783,10 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
 	/* Re-check under ptl */
 	if (likely(!vmf_pte_changed(vmf))) {
 		struct folio *folio = page_folio(page);
+		int type = is_cow ? MM_ANONPAGES : mm_counter_file(folio);
 
 		set_pte_range(vmf, folio, page, 1, vmf->address);
+		add_mm_counter(vma->vm_mm, type, 1);
 		ret = 0;
 	} else {
 		update_mmu_tlb(vma, vmf->address, vmf->pte);
@@ -5030,9 +5067,11 @@ static vm_fault_t do_fault(struct vm_fault *vmf)
 	return ret;
 }
 
-int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma,
+int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf,
 		      unsigned long addr, int page_nid, int *flags)
 {
+	struct vm_area_struct *vma = vmf->vma;
+
 	folio_get(folio);
 
 	/* Record the current PID acceesing VMA */
@@ -5044,7 +5083,55 @@ int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma,
 		*flags |= TNF_FAULT_LOCAL;
 	}
 
-	return mpol_misplaced(folio, vma, addr);
+	return mpol_misplaced(folio, vmf, addr);
+}
+
+static void numa_rebuild_single_mapping(struct vm_fault *vmf, struct vm_area_struct *vma,
+					unsigned long fault_addr, pte_t *fault_pte,
+					bool writable)
+{
+	pte_t pte, old_pte;
+
+	old_pte = ptep_modify_prot_start(vma, fault_addr, fault_pte);
+	pte = pte_modify(old_pte, vma->vm_page_prot);
+	pte = pte_mkyoung(pte);
+	if (writable)
+		pte = pte_mkwrite(pte, vma);
+	ptep_modify_prot_commit(vma, fault_addr, fault_pte, old_pte, pte);
+	update_mmu_cache_range(vmf, vma, fault_addr, fault_pte, 1);
+}
+
+static void numa_rebuild_large_mapping(struct vm_fault *vmf, struct vm_area_struct *vma,
+				       struct folio *folio, pte_t fault_pte,
+				       bool ignore_writable, bool pte_write_upgrade)
+{
+	int nr = pte_pfn(fault_pte) - folio_pfn(folio);
+	unsigned long start = max(vmf->address - nr * PAGE_SIZE, vma->vm_start);
+	unsigned long end = min(vmf->address + (folio_nr_pages(folio) - nr) * PAGE_SIZE, vma->vm_end);
+	pte_t *start_ptep = vmf->pte - (vmf->address - start) / PAGE_SIZE;
+	unsigned long addr;
+
+	/* Restore all PTEs' mapping of the large folio */
+	for (addr = start; addr != end; start_ptep++, addr += PAGE_SIZE) {
+		pte_t ptent = ptep_get(start_ptep);
+		bool writable = false;
+
+		if (!pte_present(ptent) || !pte_protnone(ptent))
+			continue;
+
+		if (pfn_folio(pte_pfn(ptent)) != folio)
+			continue;
+
+		if (!ignore_writable) {
+			ptent = pte_modify(ptent, vma->vm_page_prot);
+			writable = pte_write(ptent);
+			if (!writable && pte_write_upgrade &&
+			    can_change_pte_writable(vma, addr, ptent))
+				writable = true;
+		}
+
+		numa_rebuild_single_mapping(vmf, vma, addr, start_ptep, writable);
+	}
 }
 
 static vm_fault_t do_numa_page(struct vm_fault *vmf)
@@ -5052,11 +5139,12 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	struct vm_area_struct *vma = vmf->vma;
 	struct folio *folio = NULL;
 	int nid = NUMA_NO_NODE;
-	bool writable = false;
+	bool writable = false, ignore_writable = false;
+	bool pte_write_upgrade = vma_wants_manual_pte_write_upgrade(vma);
 	int last_cpupid;
 	int target_nid;
 	pte_t pte, old_pte;
-	int flags = 0;
+	int flags = 0, nr_pages;
 
 	/*
 	 * The pte cannot be used safely until we verify, while holding the page
@@ -5078,7 +5166,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	 * is only valid while holding the PT lock.
 	 */
 	writable = pte_write(pte);
-	if (!writable && vma_wants_manual_pte_write_upgrade(vma) &&
+	if (!writable && pte_write_upgrade &&
 	    can_change_pte_writable(vma, vmf->address, pte))
 		writable = true;
 
@@ -5086,10 +5174,6 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	if (!folio || folio_is_zone_device(folio))
 		goto out_map;
 
-	/* TODO: handle PTE-mapped THP */
-	if (folio_test_large(folio))
-		goto out_map;
-
 	/*
 	 * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
 	 * much anyway since they can be in shared cache state. This misses
@@ -5105,10 +5189,11 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	 * Flag if the folio is shared between multiple address spaces. This
 	 * is later used when determining whether to group tasks together
 	 */
-	if (folio_estimated_sharers(folio) > 1 && (vma->vm_flags & VM_SHARED))
+	if (folio_likely_mapped_shared(folio) && (vma->vm_flags & VM_SHARED))
 		flags |= TNF_SHARED;
 
 	nid = folio_nid(folio);
+	nr_pages = folio_nr_pages(folio);
 	/*
 	 * For memory tiering mode, cpupid of slow memory page is used
 	 * to record page access time.  So use default value.
@@ -5118,13 +5203,14 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 		last_cpupid = (-1 & LAST_CPUPID_MASK);
 	else
 		last_cpupid = folio_last_cpupid(folio);
-	target_nid = numa_migrate_prep(folio, vma, vmf->address, nid, &flags);
+	target_nid = numa_migrate_prep(folio, vmf, vmf->address, nid, &flags);
 	if (target_nid == NUMA_NO_NODE) {
 		folio_put(folio);
 		goto out_map;
 	}
 	pte_unmap_unlock(vmf->pte, vmf->ptl);
 	writable = false;
+	ignore_writable = true;
 
 	/* Migrate to the requested node */
 	if (migrate_misplaced_folio(folio, vma, target_nid)) {
@@ -5145,20 +5231,19 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 
 out:
 	if (nid != NUMA_NO_NODE)
-		task_numa_fault(last_cpupid, nid, 1, flags);
+		task_numa_fault(last_cpupid, nid, nr_pages, flags);
 	return 0;
 out_map:
 	/*
 	 * Make it present again, depending on how arch implements
 	 * non-accessible ptes, some can allow access by kernel mode.
 	 */
-	old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
-	pte = pte_modify(old_pte, vma->vm_page_prot);
-	pte = pte_mkyoung(pte);
-	if (writable)
-		pte = pte_mkwrite(pte, vma);
-	ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
-	update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1);
+	if (folio && folio_test_large(folio))
+		numa_rebuild_large_mapping(vmf, vma, folio, pte, ignore_writable,
+					   pte_write_upgrade);
+	else
+		numa_rebuild_single_mapping(vmf, vma, vmf->address, vmf->pte,
+					    writable);
 	pte_unmap_unlock(vmf->pte, vmf->ptl);
 	goto out;
 }
@@ -5369,7 +5454,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
 		return VM_FAULT_OOM;
 retry_pud:
 	if (pud_none(*vmf.pud) &&
-	    thp_vma_allowable_order(vma, vm_flags, false, true, true, PUD_ORDER)) {
+	    thp_vma_allowable_order(vma, vm_flags,
+				TVA_IN_PF | TVA_ENFORCE_SYSFS, PUD_ORDER)) {
 		ret = create_huge_pud(&vmf);
 		if (!(ret & VM_FAULT_FALLBACK))
 			return ret;
@@ -5403,7 +5489,8 @@ retry_pud:
 		goto retry_pud;
 
 	if (pmd_none(*vmf.pmd) &&
-	    thp_vma_allowable_order(vma, vm_flags, false, true, true, PMD_ORDER)) {
+	    thp_vma_allowable_order(vma, vm_flags,
+				TVA_IN_PF | TVA_ENFORCE_SYSFS, PMD_ORDER)) {
 		ret = create_huge_pmd(&vmf);
 		if (!(ret & VM_FAULT_FALLBACK))
 			return ret;
@@ -5757,15 +5844,6 @@ retry:
 	if (!vma_start_read(vma))
 		goto inval;
 
-	/*
-	 * find_mergeable_anon_vma uses adjacent vmas which are not locked.
-	 * This check must happen after vma_start_read(); otherwise, a
-	 * concurrent mremap() with MREMAP_DONTUNMAP could dissociate the VMA
-	 * from its anon_vma.
-	 */
-	if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma))
-		goto inval_end_read;
-
 	/* Check since vm_start/vm_end might change before we lock the VMA */
 	if (unlikely(address < vma->vm_start || address >= vma->vm_end))
 		goto inval_end_read;
@@ -5863,34 +5941,48 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 
 /**
  * follow_pte - look up PTE at a user virtual address
- * @mm: the mm_struct of the target address space
+ * @vma: the memory mapping
  * @address: user virtual address
  * @ptepp: location to store found PTE
  * @ptlp: location to store the lock for the PTE
  *
  * On a successful return, the pointer to the PTE is stored in @ptepp;
  * the corresponding lock is taken and its location is stored in @ptlp.
- * The contents of the PTE are only stable until @ptlp is released;
- * any further use, if any, must be protected against invalidation
- * with MMU notifiers.
+ *
+ * The contents of the PTE are only stable until @ptlp is released using
+ * pte_unmap_unlock(). This function will fail if the PTE is non-present.
+ * Present PTEs may include PTEs that map refcounted pages, such as
+ * anonymous folios in COW mappings.
+ *
+ * Callers must be careful when relying on PTE content after
+ * pte_unmap_unlock(). Especially if the PTE maps a refcounted page,
+ * callers must protect against invalidation with MMU notifiers; otherwise
+ * access to the PFN at a later point in time can trigger use-after-free.
  *
  * Only IO mappings and raw PFN mappings are allowed.  The mmap semaphore
  * should be taken for read.
  *
- * KVM uses this function.  While it is arguably less bad than ``follow_pfn``,
- * it is not a good general-purpose API.
+ * This function must not be used to modify PTE content.
  *
  * Return: zero on success, -ve otherwise.
  */
-int follow_pte(struct mm_struct *mm, unsigned long address,
+int follow_pte(struct vm_area_struct *vma, unsigned long address,
 	       pte_t **ptepp, spinlock_t **ptlp)
 {
+	struct mm_struct *mm = vma->vm_mm;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *ptep;
 
+	mmap_assert_locked(mm);
+	if (unlikely(address < vma->vm_start || address >= vma->vm_end))
+		goto out;
+
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out;
+
 	pgd = pgd_offset(mm, address);
 	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
 		goto out;
@@ -5920,71 +6012,7 @@ out:
 }
 EXPORT_SYMBOL_GPL(follow_pte);
 
-/**
- * follow_pfn - look up PFN at a user virtual address
- * @vma: memory mapping
- * @address: user virtual address
- * @pfn: location to store found PFN
- *
- * Only IO mappings and raw PFN mappings are allowed.
- *
- * This function does not allow the caller to read the permissions
- * of the PTE.  Do not use it.
- *
- * Return: zero and the pfn at @pfn on success, -ve otherwise.
- */
-int follow_pfn(struct vm_area_struct *vma, unsigned long address,
-	unsigned long *pfn)
-{
-	int ret = -EINVAL;
-	spinlock_t *ptl;
-	pte_t *ptep;
-
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		return ret;
-
-	ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
-	if (ret)
-		return ret;
-	*pfn = pte_pfn(ptep_get(ptep));
-	pte_unmap_unlock(ptep, ptl);
-	return 0;
-}
-EXPORT_SYMBOL(follow_pfn);
-
 #ifdef CONFIG_HAVE_IOREMAP_PROT
-int follow_phys(struct vm_area_struct *vma,
-		unsigned long address, unsigned int flags,
-		unsigned long *prot, resource_size_t *phys)
-{
-	int ret = -EINVAL;
-	pte_t *ptep, pte;
-	spinlock_t *ptl;
-
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		goto out;
-
-	if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
-		goto out;
-	pte = ptep_get(ptep);
-
-	/* Never return PFNs of anon folios in COW mappings. */
-	if (vm_normal_folio(vma, address, pte))
-		goto unlock;
-
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
-		goto unlock;
-
-	*prot = pgprot_val(pte_pgprot(pte));
-	*phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
-
-	ret = 0;
-unlock:
-	pte_unmap_unlock(ptep, ptl);
-out:
-	return ret;
-}
-
 /**
  * generic_access_phys - generic implementation for iomem mmap access
  * @vma: the vma to access
@@ -6008,11 +6036,8 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
 	int offset = offset_in_page(addr);
 	int ret = -EINVAL;
 
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		return -EINVAL;
-
 retry:
-	if (follow_pte(vma->vm_mm, addr, &ptep, &ptl))
+	if (follow_pte(vma, addr, &ptep, &ptl))
 		return -EINVAL;
 	pte = ptep_get(ptep);
 	pte_unmap_unlock(ptep, ptl);
@@ -6027,7 +6052,7 @@ retry:
 	if (!maddr)
 		return -ENOMEM;
 
-	if (follow_pte(vma->vm_mm, addr, &ptep, &ptl))
+	if (follow_pte(vma, addr, &ptep, &ptl))
 		goto out_unmap;
 
 	if (!pte_same(pte, ptep_get(ptep))) {
@@ -6435,3 +6460,15 @@ void ptlock_free(struct ptdesc *ptdesc)
 	kmem_cache_free(page_ptl_cachep, ptdesc->ptl);
 }
 #endif
+
+void vma_pgtable_walk_begin(struct vm_area_struct *vma)
+{
+	if (is_vm_hugetlb_page(vma))
+		hugetlb_vma_lock_read(vma);
+}
+
+void vma_pgtable_walk_end(struct vm_area_struct *vma)
+{
+	if (is_vm_hugetlb_page(vma))
+		hugetlb_vma_unlock_read(vma);
+}