1 files changed, 67 insertions, 28 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 098f00d05461..305537fc8640 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -789,6 +789,46 @@ out:
         return pfn_to_page(pfn);
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
+                                pmd_t pmd)
+{
+        unsigned long pfn = pmd_pfn(pmd);
+
+        /*
+         * There is no pmd_special() but there may be special pmds, e.g.
+         * in a direct-access (dax) mapping, so let's just replicate the
+         * !HAVE_PTE_SPECIAL case from vm_normal_page() here.
+         */
+        if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
+                if (vma->vm_flags & VM_MIXEDMAP) {
+                        if (!pfn_valid(pfn))
+                                return NULL;
+                        goto out;
+                } else {
+                        unsigned long off;
+                        off = (addr - vma->vm_start) >> PAGE_SHIFT;
+                        if (pfn == vma->vm_pgoff + off)
+                                return NULL;
+                        if (!is_cow_mapping(vma->vm_flags))
+                                return NULL;
+                }
+        }
+
+        if (is_zero_pfn(pfn))
+                return NULL;
+        if (unlikely(pfn > highest_memmap_pfn))
+                return NULL;
+
+        /*
+         * NOTE! We still have PageReserved() pages in the page tables.
+         * eg. VDSO mappings can cause them to exist.
+         */
+out:
+        return pfn_to_page(pfn);
+}
+#endif
+
 /*
  * copy one vm_area from one task to the other. Assumes the page tables
  * already present in the new task to be cleared in the whole range
@@ -2054,7 +2094,7 @@ static inline int wp_page_reuse(struct mm_struct *mm,
                 VM_BUG_ON_PAGE(PageAnon(page), page);
                 mapping = page->mapping;
                 unlock_page(page);
-                page_cache_release(page);
+                put_page(page);
 
                 if ((dirtied || page_mkwrite) && mapping) {
                         /*
@@ -2188,7 +2228,7 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
         }
 
         if (new_page)
-                page_cache_release(new_page);
+                put_page(new_page);
 
         pte_unmap_unlock(page_table, ptl);
         mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
@@ -2203,14 +2243,14 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
                                 munlock_vma_page(old_page);
                         unlock_page(old_page);
                 }
-                page_cache_release(old_page);
+                put_page(old_page);
         }
         return page_copied ? VM_FAULT_WRITE : 0;
 oom_free_new:
-        page_cache_release(new_page);
+        put_page(new_page);
 oom:
         if (old_page)
-                page_cache_release(old_page);
+                put_page(old_page);
         return VM_FAULT_OOM;
 }
 
@@ -2258,7 +2298,7 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
 {
         int page_mkwrite = 0;
 
-        page_cache_get(old_page);
+        get_page(old_page);
 
         if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
                 int tmp;
@@ -2267,7 +2307,7 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
                 tmp = do_page_mkwrite(vma, old_page, address);
                 if (unlikely(!tmp || (tmp &
                                       (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
-                        page_cache_release(old_page);
+                        put_page(old_page);
                         return tmp;
                 }
                 /*
@@ -2281,7 +2321,7 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
                 if (!pte_same(*page_table, orig_pte)) {
                         unlock_page(old_page);
                         pte_unmap_unlock(page_table, ptl);
-                        page_cache_release(old_page);
+                        put_page(old_page);
                         return 0;
                 }
                 page_mkwrite = 1;
@@ -2341,7 +2381,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
          */
         if (PageAnon(old_page) && !PageKsm(old_page)) {
                 if (!trylock_page(old_page)) {
-                        page_cache_get(old_page);
+                        get_page(old_page);
                         pte_unmap_unlock(page_table, ptl);
                         lock_page(old_page);
                         page_table = pte_offset_map_lock(mm, pmd, address,
@@ -2349,10 +2389,10 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
                         if (!pte_same(*page_table, orig_pte)) {
                                 unlock_page(old_page);
                                 pte_unmap_unlock(page_table, ptl);
-                                page_cache_release(old_page);
+                                put_page(old_page);
                                 return 0;
                         }
-                        page_cache_release(old_page);
+                        put_page(old_page);
                 }
                 if (reuse_swap_page(old_page)) {
                         /*
@@ -2375,7 +2415,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
         /*
          * Ok, we need to copy. Oh, well..
          */
-        page_cache_get(old_page);
+        get_page(old_page);
 
         pte_unmap_unlock(page_table, ptl);
         return wp_page_copy(mm, vma, address, page_table, pmd,
@@ -2400,7 +2440,6 @@ static inline void unmap_mapping_range_tree(struct rb_root *root,
 
                 vba = vma->vm_pgoff;
                 vea = vba + vma_pages(vma) - 1;
-                /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
                 zba = details->first_index;
                 if (zba < vba)
                         zba = vba;
@@ -2619,7 +2658,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                  * parallel locked swapcache.
                  */
                 unlock_page(swapcache);
-                page_cache_release(swapcache);
+                put_page(swapcache);
         }
 
         if (flags & FAULT_FLAG_WRITE) {
@@ -2641,10 +2680,10 @@ out_nomap:
 out_page:
         unlock_page(page);
 out_release:
-        page_cache_release(page);
+        put_page(page);
         if (page != swapcache) {
                 unlock_page(swapcache);
-                page_cache_release(swapcache);
+                put_page(swapcache);
         }
         return ret;
 }
@@ -2752,7 +2791,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
         if (userfaultfd_missing(vma)) {
                 pte_unmap_unlock(page_table, ptl);
                 mem_cgroup_cancel_charge(page, memcg, false);
-                page_cache_release(page);
+                put_page(page);
                 return handle_userfault(vma, address, flags,
                                         VM_UFFD_MISSING);
         }
@@ -2771,10 +2810,10 @@ unlock:
         return 0;
 release:
         mem_cgroup_cancel_charge(page, memcg, false);
-        page_cache_release(page);
+        put_page(page);
         goto unlock;
 oom_free_page:
-        page_cache_release(page);
+        put_page(page);
 oom:
         return VM_FAULT_OOM;
 }
@@ -2807,7 +2846,7 @@ static int __do_fault(struct vm_area_struct *vma, unsigned long address,
         if (unlikely(PageHWPoison(vmf.page))) {
                 if (ret & VM_FAULT_LOCKED)
                         unlock_page(vmf.page);
-                page_cache_release(vmf.page);
+                put_page(vmf.page);
                 return VM_FAULT_HWPOISON;
         }
 
@@ -2996,7 +3035,7 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         if (unlikely(!pte_same(*pte, orig_pte))) {
                 pte_unmap_unlock(pte, ptl);
                 unlock_page(fault_page);
-                page_cache_release(fault_page);
+                put_page(fault_page);
                 return ret;
         }
         do_set_pte(vma, address, fault_page, pte, false, false);
@@ -3024,7 +3063,7 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                 return VM_FAULT_OOM;
 
         if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg, false)) {
-                page_cache_release(new_page);
+                put_page(new_page);
                 return VM_FAULT_OOM;
         }
 
@@ -3041,7 +3080,7 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                 pte_unmap_unlock(pte, ptl);
                 if (fault_page) {
                         unlock_page(fault_page);
-                        page_cache_release(fault_page);
+                        put_page(fault_page);
                 } else {
                         /*
                          * The fault handler has no page to lock, so it holds
@@ -3057,7 +3096,7 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         pte_unmap_unlock(pte, ptl);
         if (fault_page) {
                 unlock_page(fault_page);
-                page_cache_release(fault_page);
+                put_page(fault_page);
         } else {
                 /*
                  * The fault handler has no page to lock, so it holds
@@ -3068,7 +3107,7 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         return ret;
 uncharge_out:
         mem_cgroup_cancel_charge(new_page, memcg, false);
-        page_cache_release(new_page);
+        put_page(new_page);
         return ret;
 }
 
@@ -3096,7 +3135,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                 tmp = do_page_mkwrite(vma, fault_page, address);
                 if (unlikely(!tmp ||
                                 (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
-                        page_cache_release(fault_page);
+                        put_page(fault_page);
                         return tmp;
                 }
         }
@@ -3105,7 +3144,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         if (unlikely(!pte_same(*pte, orig_pte))) {
                 pte_unmap_unlock(pte, ptl);
                 unlock_page(fault_page);
-                page_cache_release(fault_page);
+                put_page(fault_page);
                 return ret;
         }
         do_set_pte(vma, address, fault_page, pte, true, false);
@@ -3736,7 +3775,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
                                                     buf, maddr + offset, bytes);
                         }
                         kunmap(page);
-                        page_cache_release(page);
+                        put_page(page);
                 }
                 len -= bytes;
                 buf += bytes;