mm/hwpoison: fix refcount of THP head page in no-injection case

[deliverable/linux.git] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index 82db4fc0a9d34040bf7fa6750eddf7b508fb0e1a..52a2373d0ed421b10fcc01ac57ed4a7504575a49 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2884,7 +2884,7 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
         * using the existing file pgoff checks and manipulations.
         * Similarly in do_mmap_pgoff and in do_brk.
         */
-       if (!vma->vm_file) {
+       if (vma_is_anonymous(vma)) {
                BUG_ON(vma->anon_vma);
                vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
        }
@@ -2918,7 +2918,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
         * If anonymous vma has not yet been faulted, update new pgoff
         * to match new location, to increase its chance of merging.
         */
-       if (unlikely(!vma->vm_file && !vma->anon_vma)) {
+       if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
                pgoff = addr >> PAGE_SHIFT;
                faulted_in_anon_vma = false;
        }
@@ -3027,21 +3027,13 @@ static int special_mapping_fault(struct vm_area_struct *vma,
        pgoff_t pgoff;
        struct page **pages;
 
-       /*
-        * special mappings have no vm_file, and in that case, the mm
-        * uses vm_pgoff internally. So we have to subtract it from here.
-        * We are allowed to do this because we are the mm; do not copy
-        * this code into drivers!
-        */
-       pgoff = vmf->pgoff - vma->vm_pgoff;
-
        if (vma->vm_ops == &legacy_special_mapping_vmops)
                pages = vma->vm_private_data;
        else
                pages = ((struct vm_special_mapping *)vma->vm_private_data)->
                        pages;
 
-       for (; pgoff && *pages; ++pages)
+       for (pgoff = vmf->pgoff; pgoff && *pages; ++pages)
                pgoff--;
 
        if (*pages) {