[3/4,Zesty,SRU] Revert "mm: introduce page_vma_mapped_walk()"

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index b76343610653..15321fb1df6b 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -9,7 +9,6 @@ 
 #include <linux/mm.h>
 #include <linux/rwsem.h>
 #include <linux/memcontrol.h>
-#include <linux/highmem.h>
 
 /*
  * The anon_vma heads a list of private "related" vmas, to scan if
@@ -233,31 +232,6 @@  static inline bool page_check_address_transhuge(struct page *page,
 }
 #endif
 
-/* Avoid racy checks */
-#define PVMW_SYNC		(1 << 0)
-/* Look for migarion entries rather than present PTEs */
-#define PVMW_MIGRATION		(1 << 1)
-
-struct page_vma_mapped_walk {
-	struct page *page;
-	struct vm_area_struct *vma;
-	unsigned long address;
-	pmd_t *pmd;
-	pte_t *pte;
-	spinlock_t *ptl;
-	unsigned int flags;
-};
-
-static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
-{
-	if (pvmw->pte)
-		pte_unmap(pvmw->pte);
-	if (pvmw->ptl)
-		spin_unlock(pvmw->ptl);
-}
-
-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
-
 /*
  * Used by swapoff to help locate where page is expected in vma.
  */
diff --git a/mm/Makefile b/mm/Makefile
index 474fa3431059..14fa1c83b504 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -23,10 +23,8 @@  KCOV_INSTRUMENT_vmstat.o := n
 
 mmu-y			:= nommu.o
 mmu-$(CONFIG_MMU)	:= gup.o highmem.o memory.o mincore.o \
-			   mlock.o mmap.o mprotect.o mremap.o msync.o \
-			   page_vma_mapped.o pagewalk.o pgtable-generic.o \
-			   rmap.o vmalloc.o
-
+			   mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
+			   vmalloc.o pagewalk.o pgtable-generic.o
 
 ifdef CONFIG_CROSS_MEMORY_ATTACH
 mmu-$(CONFIG_MMU)	+= process_vm_access.o
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 87303c6bacf4..e6de801fa477 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1878,12 +1878,9 @@  static void freeze_page(struct page *page)
 static void unfreeze_page(struct page *page)
 {
 	int i;
-	if (PageTransHuge(page)) {
-		remove_migration_ptes(page, page, true);
-	} else {
-		for (i = 0; i < HPAGE_PMD_NR; i++)
-			remove_migration_ptes(page + i, page + i, true);
-	}
+
+	for (i = 0; i < HPAGE_PMD_NR; i++)
+		remove_migration_ptes(page + i, page + i, true);
 }
 
 static void __split_huge_page_tail(struct page *head, int tail,
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
deleted file mode 100644
index dc1a54826cf2..000000000000
--- a/mm/page_vma_mapped.c
+++ /dev/null
@@ -1,188 +0,0 @@ 
-#include <linux/mm.h>
-#include <linux/rmap.h>
-#include <linux/hugetlb.h>
-#include <linux/swap.h>
-#include <linux/swapops.h>
-
-#include "internal.h"
-
-static inline bool check_pmd(struct page_vma_mapped_walk *pvmw)
-{
-	pmd_t pmde;
-	/*
-	 * Make sure we don't re-load pmd between present and !trans_huge check.
-	 * We need a consistent view.
-	 */
-	pmde = READ_ONCE(*pvmw->pmd);
-	return pmd_present(pmde) && !pmd_trans_huge(pmde);
-}
-
-static inline bool not_found(struct page_vma_mapped_walk *pvmw)
-{
-	page_vma_mapped_walk_done(pvmw);
-	return false;
-}
-
-static bool map_pte(struct page_vma_mapped_walk *pvmw)
-{
-	pvmw->pte = pte_offset_map(pvmw->pmd, pvmw->address);
-	if (!(pvmw->flags & PVMW_SYNC)) {
-		if (pvmw->flags & PVMW_MIGRATION) {
-			if (!is_swap_pte(*pvmw->pte))
-				return false;
-		} else {
-			if (!pte_present(*pvmw->pte))
-				return false;
-		}
-	}
-	pvmw->ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd);
-	spin_lock(pvmw->ptl);
-	return true;
-}
-
-static bool check_pte(struct page_vma_mapped_walk *pvmw)
-{
-	if (pvmw->flags & PVMW_MIGRATION) {
-#ifdef CONFIG_MIGRATION
-		swp_entry_t entry;
-		if (!is_swap_pte(*pvmw->pte))
-			return false;
-		entry = pte_to_swp_entry(*pvmw->pte);
-		if (!is_migration_entry(entry))
-			return false;
-		if (migration_entry_to_page(entry) - pvmw->page >=
-				hpage_nr_pages(pvmw->page)) {
-			return false;
-		}
-		if (migration_entry_to_page(entry) < pvmw->page)
-			return false;
-#else
-		WARN_ON_ONCE(1);
-#endif
-	} else {
-		if (!pte_present(*pvmw->pte))
-			return false;
-
-		/* THP can be referenced by any subpage */
-		if (pte_page(*pvmw->pte) - pvmw->page >=
-				hpage_nr_pages(pvmw->page)) {
-			return false;
-		}
-		if (pte_page(*pvmw->pte) < pvmw->page)
-			return false;
-	}
-
-	return true;
-}
-
-/**
- * page_vma_mapped_walk - check if @pvmw->page is mapped in @pvmw->vma at
- * @pvmw->address
- * @pvmw: pointer to struct page_vma_mapped_walk. page, vma, address and flags
- * must be set. pmd, pte and ptl must be NULL.
- *
- * Returns true if the page is mapped in the vma. @pvmw->pmd and @pvmw->pte point
- * to relevant page table entries. @pvmw->ptl is locked. @pvmw->address is
- * adjusted if needed (for PTE-mapped THPs).
- *
- * If @pvmw->pmd is set but @pvmw->pte is not, you have found PMD-mapped page
- * (usually THP). For PTE-mapped THP, you should run page_vma_mapped_walk() in
- * a loop to find all PTEs that map the THP.
- *
- * For HugeTLB pages, @pvmw->pte is set to the relevant page table entry
- * regardless of which page table level the page is mapped at. @pvmw->pmd is
- * NULL.
- *
- * Retruns false if there are no more page table entries for the page in
- * the vma. @pvmw->ptl is unlocked and @pvmw->pte is unmapped.
- *
- * If you need to stop the walk before page_vma_mapped_walk() returned false,
- * use page_vma_mapped_walk_done(). It will do the housekeeping.
- */
-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
-{
-	struct mm_struct *mm = pvmw->vma->vm_mm;
-	struct page *page = pvmw->page;
-	pgd_t *pgd;
-	pud_t *pud;
-
-	/* The only possible pmd mapping has been handled on last iteration */
-	if (pvmw->pmd && !pvmw->pte)
-		return not_found(pvmw);
-
-	/* Only for THP, seek to next pte entry makes sense */
-	if (pvmw->pte) {
-		if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page))
-			return not_found(pvmw);
-		goto next_pte;
-	}
-
-	if (unlikely(PageHuge(pvmw->page))) {
-		/* when pud is not present, pte will be NULL */
-		pvmw->pte = huge_pte_offset(mm, pvmw->address);
-		if (!pvmw->pte)
-			return false;
-
-		pvmw->ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte);
-		spin_lock(pvmw->ptl);
-		if (!check_pte(pvmw))
-			return not_found(pvmw);
-		return true;
-	}
-restart:
-	pgd = pgd_offset(mm, pvmw->address);
-	if (!pgd_present(*pgd))
-		return false;
-	pud = pud_offset(pgd, pvmw->address);
-	if (!pud_present(*pud))
-		return false;
-	pvmw->pmd = pmd_offset(pud, pvmw->address);
-	if (pmd_trans_huge(*pvmw->pmd)) {
-		pvmw->ptl = pmd_lock(mm, pvmw->pmd);
-		if (!pmd_present(*pvmw->pmd))
-			return not_found(pvmw);
-		if (likely(pmd_trans_huge(*pvmw->pmd))) {
-			if (pvmw->flags & PVMW_MIGRATION)
-				return not_found(pvmw);
-			if (pmd_page(*pvmw->pmd) != page)
-				return not_found(pvmw);
-			return true;
-		} else {
-			/* THP pmd was split under us: handle on pte level */
-			spin_unlock(pvmw->ptl);
-			pvmw->ptl = NULL;
-		}
-	} else {
-		if (!check_pmd(pvmw))
-			return false;
-	}
-	if (!map_pte(pvmw))
-		goto next_pte;
-	while (1) {
-		if (check_pte(pvmw))
-			return true;
-next_pte:	do {
-			pvmw->address += PAGE_SIZE;
-			if (pvmw->address >=
-					__vma_address(pvmw->page, pvmw->vma) +
-					hpage_nr_pages(pvmw->page) * PAGE_SIZE)
-				return not_found(pvmw);
-			/* Did we cross page table boundary? */
-			if (pvmw->address % PMD_SIZE == 0) {
-				pte_unmap(pvmw->pte);
-				if (pvmw->ptl) {
-					spin_unlock(pvmw->ptl);
-					pvmw->ptl = NULL;
-				}
-				goto restart;
-			} else {
-				pvmw->pte++;
-			}
-		} while (pte_none(*pvmw->pte));
-
-		if (!pvmw->ptl) {
-			pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
-			spin_lock(pvmw->ptl);
-		}
-	}
-}