1 files changed, 49 insertions, 2 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 072c1135ad37..e7066e71dfa3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1277,6 +1277,51 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *
 }
 EXPORT_SYMBOL(vm_insert_page);
 
+/**
+ * vm_insert_pfn - insert single pfn into user vma
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @pfn: source kernel pfn
+ *
+ * Similar to vm_inert_page, this allows drivers to insert individual pages
+ * they've allocated into a user vma. Same comments apply.
+ *
+ * This function should only be called from a vm_ops->fault handler, and
+ * in that case the handler should return NULL.
+ */
+int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
+                unsigned long pfn)
+{
+        struct mm_struct *mm = vma->vm_mm;
+        int retval;
+        pte_t *pte, entry;
+        spinlock_t *ptl;
+
+        BUG_ON(!(vma->vm_flags & VM_PFNMAP));
+        BUG_ON(is_cow_mapping(vma->vm_flags));
+
+        retval = -ENOMEM;
+        pte = get_locked_pte(mm, addr, &ptl);
+        if (!pte)
+                goto out;
+        retval = -EBUSY;
+        if (!pte_none(*pte))
+                goto out_unlock;
+
+        /* Ok, finally just insert the thing.. */
+        entry = pfn_pte(pfn, vma->vm_page_prot);
+        set_pte_at(mm, addr, pte, entry);
+        update_mmu_cache(vma, addr, entry);
+
+        retval = 0;
+out_unlock:
+        pte_unmap_unlock(pte, ptl);
+
+out:
+        return retval;
+}
+EXPORT_SYMBOL(vm_insert_pfn);
+
 /*
  * maps a range of physical memory into the requested pages. the old
  * mappings are removed. any references to nonexistent pages results
@@ -2310,10 +2355,12 @@ static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma,
         BUG_ON(is_cow_mapping(vma->vm_flags));
 
         pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK);
-        if (pfn == NOPFN_OOM)
+        if (unlikely(pfn == NOPFN_OOM))
                 return VM_FAULT_OOM;
-        if (pfn == NOPFN_SIGBUS)
+        else if (unlikely(pfn == NOPFN_SIGBUS))
                 return VM_FAULT_SIGBUS;
+        else if (unlikely(pfn == NOPFN_REFAULT))
+                return VM_FAULT_MINOR;
 
         page_table = pte_offset_map_lock(mm, pmd, address, &ptl);