1 files changed, 31 insertions, 47 deletions

diff --git a/mm/msync.c b/mm/msync.c
index d0f5a1bce7..0e040e9c39 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -17,40 +17,48 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 
-/*
- * Called with mm->page_table_lock held to protect against other
- * threads/the swapper from ripping pte's out from under us.
- */
-
-static void sync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
+static void msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                                 unsigned long addr, unsigned long end)
 {
         pte_t *pte;
+        spinlock_t *ptl;
+        int progress = 0;
 
-        pte = pte_offset_map(pmd, addr);
+again:
+        pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
         do {
                 unsigned long pfn;
                 struct page *page;
 
+                if (progress >= 64) {
+                        progress = 0;
+                        if (need_resched() || need_lockbreak(ptl))
+                                break;
+                }
+                progress++;
                 if (!pte_present(*pte))
                         continue;
                 if (!pte_maybe_dirty(*pte))
                         continue;
                 pfn = pte_pfn(*pte);
-                if (!pfn_valid(pfn))
+                if (unlikely(!pfn_valid(pfn))) {
+                        print_bad_pte(vma, *pte, addr);
                         continue;
+                }
                 page = pfn_to_page(pfn);
-                if (PageReserved(page))
-                        continue;
 
                 if (ptep_clear_flush_dirty(vma, addr, pte) ||
                     page_test_and_clear_dirty(page))
                         set_page_dirty(page);
+                progress += 3;
         } while (pte++, addr += PAGE_SIZE, addr != end);
-        pte_unmap(pte - 1);
+        pte_unmap_unlock(pte - 1, ptl);
+        cond_resched();
+        if (addr != end)
+                goto again;
 }
 
-static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
+static inline void msync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
                                 unsigned long addr, unsigned long end)
 {
         pmd_t *pmd;
@@ -61,11 +69,11 @@ static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
                 next = pmd_addr_end(addr, end);
                 if (pmd_none_or_clear_bad(pmd))
                         continue;
-                sync_pte_range(vma, pmd, addr, next);
+                msync_pte_range(vma, pmd, addr, next);
         } while (pmd++, addr = next, addr != end);
 }
 
-static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
+static inline void msync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
                                 unsigned long addr, unsigned long end)
 {
         pud_t *pud;
@@ -76,58 +84,34 @@ static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
                 next = pud_addr_end(addr, end);
                 if (pud_none_or_clear_bad(pud))
                         continue;
-                sync_pmd_range(vma, pud, addr, next);
+                msync_pmd_range(vma, pud, addr, next);
         } while (pud++, addr = next, addr != end);
 }
 
-static void sync_page_range(struct vm_area_struct *vma,
+static void msync_page_range(struct vm_area_struct *vma,
                                 unsigned long addr, unsigned long end)
 {
-        struct mm_struct *mm = vma->vm_mm;
         pgd_t *pgd;
         unsigned long next;
 
         /* For hugepages we can't go walking the page table normally,
          * but that's ok, hugetlbfs is memory based, so we don't need
-         * to do anything more on an msync() */
-        if (is_vm_hugetlb_page(vma))
+         * to do anything more on an msync().
+         * Can't do anything with VM_RESERVED regions either.
+         */
+        if (vma->vm_flags & (VM_HUGETLB|VM_RESERVED))
                 return;
 
         BUG_ON(addr >= end);
-        pgd = pgd_offset(mm, addr);
+        pgd = pgd_offset(vma->vm_mm, addr);
         flush_cache_range(vma, addr, end);
-        spin_lock(&mm->page_table_lock);
         do {
                 next = pgd_addr_end(addr, end);
                 if (pgd_none_or_clear_bad(pgd))
                         continue;
-                sync_pud_range(vma, pgd, addr, next);
+                msync_pud_range(vma, pgd, addr, next);
         } while (pgd++, addr = next, addr != end);
-        spin_unlock(&mm->page_table_lock);
-}
-
-#ifdef CONFIG_PREEMPT
-static inline void filemap_sync(struct vm_area_struct *vma,
-                                unsigned long addr, unsigned long end)
-{
-        const size_t chunk = 64 * 1024; /* bytes */
-        unsigned long next;
-
-        do {
-                next = addr + chunk;
-                if (next > end || next < addr)
-                        next = end;
-                sync_page_range(vma, addr, next);
-                cond_resched();
-        } while (addr = next, addr != end);
-}
-#else
-static inline void filemap_sync(struct vm_area_struct *vma,
-                                unsigned long addr, unsigned long end)
-{
-        sync_page_range(vma, addr, end);
 }
-#endif
 
 /*
  * MS_SYNC syncs the entire file - including mappings.
@@ -150,7 +134,7 @@ static int msync_interval(struct vm_area_struct *vma,
                 return -EBUSY;
 
         if (file && (vma->vm_flags & VM_SHARED)) {
-                filemap_sync(vma, addr, end);
+                msync_page_range(vma, addr, end);
 
                 if (flags & MS_SYNC) {
                         struct address_space *mapping = file->f_mapping;