Revert "mm: introduce page_vma_mapped_walk()"

BugLink: http://bugs.launchpad.net/bugs/1674838
This reverts commit 6e2a092a48d38cfc0f06bdb523014acbfeba7b2e.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index b76343610653fee971e1ee897fddc9e7bf9e8990..15321fb1df6b5a70263fef971654ec709b1731ba 100644 (file)
--- 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 474fa3431059410ce59610822b5c65c7a625f01d..14fa1c83b5042f3b6702aa3253b17ee525456a24 100644 (file)
--- 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 af1f44b35be9efb69beb65db1c32788c7bd1cb8f..49cb70b5993deddd13e54fda231f14cf414ce543 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1877,12 +1877,9 @@ 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 (file)
index dc1a548..0000000
--- 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);
-               }
-       }
-}