mm: drop support of non-linear mapping from fault codepath
We don't create non-linear mappings anymore. Let's drop code which
handles them on page fault.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index 9a3e73b..43a5374 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1899,12 +1899,11 @@
EXPORT_SYMBOL_GPL(apply_to_page_range);
/*
- * handle_pte_fault chooses page fault handler according to an entry
- * which was read non-atomically. Before making any commitment, on
- * those architectures or configurations (e.g. i386 with PAE) which
- * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
- * must check under lock before unmapping the pte and proceeding
- * (but do_wp_page is only called after already making such a check;
+ * handle_pte_fault chooses page fault handler according to an entry which was
+ * read non-atomically. Before making any commitment, on those architectures
+ * or configurations (e.g. i386 with PAE) which might give a mix of unmatched
+ * parts, do_swap_page must check under lock before unmapping the pte and
+ * proceeding (but do_wp_page is only called after already making such a check;
* and do_anonymous_page can safely check later on).
*/
static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
@@ -2710,8 +2709,6 @@
entry = mk_pte(page, vma->vm_page_prot);
if (write)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- else if (pte_file(*pte) && pte_file_soft_dirty(*pte))
- entry = pte_mksoft_dirty(entry);
if (anon) {
inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
page_add_new_anon_rmap(page, vma, address);
@@ -2846,8 +2843,7 @@
* if page by the offset is not ready to be mapped (cold cache or
* something).
*/
- if (vma->vm_ops->map_pages && !(flags & FAULT_FLAG_NONLINEAR) &&
- fault_around_bytes >> PAGE_SHIFT > 1) {
+ if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) {
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
do_fault_around(vma, address, pte, pgoff, flags);
if (!pte_same(*pte, orig_pte))
@@ -2992,7 +2988,7 @@
* The mmap_sem may have been released depending on flags and our
* return value. See filemap_fault() and __lock_page_or_retry().
*/
-static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+static int do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
unsigned int flags, pte_t orig_pte)
{
@@ -3009,46 +3005,6 @@
return do_shared_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
}
-/*
- * Fault of a previously existing named mapping. Repopulate the pte
- * from the encoded file_pte if possible. This enables swappable
- * nonlinear vmas.
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with pte unmapped and unlocked.
- * The mmap_sem may have been released depending on flags and our
- * return value. See filemap_fault() and __lock_page_or_retry().
- */
-static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, pte_t *page_table, pmd_t *pmd,
- unsigned int flags, pte_t orig_pte)
-{
- pgoff_t pgoff;
-
- flags |= FAULT_FLAG_NONLINEAR;
-
- if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
- return 0;
-
- if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
- /*
- * Page table corrupted: show pte and kill process.
- */
- print_bad_pte(vma, address, orig_pte, NULL);
- return VM_FAULT_SIGBUS;
- }
-
- pgoff = pte_to_pgoff(orig_pte);
- if (!(flags & FAULT_FLAG_WRITE))
- return do_read_fault(mm, vma, address, pmd, pgoff, flags,
- orig_pte);
- if (!(vma->vm_flags & VM_SHARED))
- return do_cow_fault(mm, vma, address, pmd, pgoff, flags,
- orig_pte);
- return do_shared_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
-}
-
static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
unsigned long addr, int page_nid,
int *flags)
@@ -3176,15 +3132,12 @@
if (pte_none(entry)) {
if (vma->vm_ops) {
if (likely(vma->vm_ops->fault))
- return do_linear_fault(mm, vma, address,
- pte, pmd, flags, entry);
+ return do_fault(mm, vma, address, pte,
+ pmd, flags, entry);
}
return do_anonymous_page(mm, vma, address,
pte, pmd, flags);
}
- if (pte_file(entry))
- return do_nonlinear_fault(mm, vma, address,
- pte, pmd, flags, entry);
return do_swap_page(mm, vma, address,
pte, pmd, flags, entry);
}