1 files changed, 31 insertions, 8 deletions

diff --git a/mm/memory.c b/mm/memory.c
index baa999e87cd2..cf6873e91c6a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1151,6 +1151,11 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
                 if ((flags & FOLL_WRITE) &&
                     !pte_dirty(pte) && !PageDirty(page))
                         set_page_dirty(page);
+                /*
+                 * pte_mkyoung() would be more correct here, but atomic care
+                 * is needed to avoid losing the dirty bit: it is easier to use
+                 * mark_page_accessed().
+                 */
                 mark_page_accessed(page);
         }
 unlock:
@@ -1665,9 +1670,10 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
          * behaviour that some programs depend on. We mark the "original"
          * un-COW'ed pages by matching them up with "vma->vm_pgoff".
          */
-        if (addr == vma->vm_start && end == vma->vm_end)
+        if (addr == vma->vm_start && end == vma->vm_end) {
                 vma->vm_pgoff = pfn;
-        else if (is_cow_mapping(vma->vm_flags))
+                vma->vm_flags |= VM_PFN_AT_MMAP;
+        } else if (is_cow_mapping(vma->vm_flags))
                 return -EINVAL;
 
         vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
@@ -1679,6 +1685,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
                  * needed from higher level routine calling unmap_vmas
                  */
                 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
+                vma->vm_flags &= ~VM_PFN_AT_MMAP;
                 return -EINVAL;
         }
 
@@ -1938,6 +1945,15 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
                  * get_user_pages(.write=1, .force=1).
                  */
                 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+                        struct vm_fault vmf;
+                        int tmp;
+
+                        vmf.virtual_address = (void __user *)(address &
+                                                                PAGE_MASK);
+                        vmf.pgoff = old_page->index;
+                        vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
+                        vmf.page = old_page;
+
                         /*
                          * Notify the address space that the page is about to
                          * become writable so that it can prohibit this or wait
@@ -1949,8 +1965,12 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
                         page_cache_get(old_page);
                         pte_unmap_unlock(page_table, ptl);
 
-                        if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
+                        tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
+                        if (unlikely(tmp &
+                                        (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
+                                ret = tmp;
                                 goto unwritable_page;
+                        }
 
                         /*
                          * Since we dropped the lock we need to revalidate
@@ -2099,7 +2119,7 @@ oom:
 
 unwritable_page:
         page_cache_release(old_page);
-        return VM_FAULT_SIGBUS;
+        return ret;
 }
 
 /*
@@ -2433,8 +2453,6 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                 count_vm_event(PGMAJFAULT);
         }
 
-        mark_page_accessed(page);
-
         lock_page(page);
         delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 
@@ -2643,9 +2661,14 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                          * to become writable
                          */
                         if (vma->vm_ops->page_mkwrite) {
+                                int tmp;
+
                                 unlock_page(page);
-                                if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
-                                        ret = VM_FAULT_SIGBUS;
+                                vmf.flags |= FAULT_FLAG_MKWRITE;
+                                tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
+                                if (unlikely(tmp &
+                                          (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
+                                        ret = tmp;
                                         anon = 1; /* no anon but release vmf.page */
                                         goto out_unlocked;
                                 }