Reinstate ZERO_PAGE optimization in 'get_user_pages()' and fix XIP

[pandora-kernel.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 19e0ae9..9aefaae 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -999,17 +999,15 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
                goto no_page_table;
 
        ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
-       if (!ptep)
-               goto out;
 
        pte = *ptep;
        if (!pte_present(pte))
-               goto unlock;
+               goto no_page;
        if ((flags & FOLL_WRITE) && !pte_write(pte))
                goto unlock;
        page = vm_normal_page(vma, address, pte);
        if (unlikely(!page))
-               goto unlock;
+               goto bad_page;
 
        if (flags & FOLL_GET)
                get_page(page);
@@ -1024,6 +1022,15 @@ unlock:
 out:
        return page;
 
+bad_page:
+       pte_unmap_unlock(ptep, ptl);
+       return ERR_PTR(-EFAULT);
+
+no_page:
+       pte_unmap_unlock(ptep, ptl);
+       if (!pte_none(pte))
+               return page;
+       /* Fall through to ZERO_PAGE handling */
 no_page_table:
        /*
         * When core dumping an enormous anonymous area that nobody
@@ -1159,6 +1166,8 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 
                                cond_resched();
                        }
+                       if (IS_ERR(page))
+                               return i ? i : PTR_ERR(page);
                        if (pages) {
                                pages[i] = page;