mm: use mm_populate() for blocking remap_file_pages()

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Cc: Greg Ungerer <gregungerer@westnet.com.au>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 16 deletions

diff --git a/mm/fremap.c b/mm/fremap.c
index 2db886e31044..b42e32171530 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -129,6 +129,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
         struct vm_area_struct *vma;
         int err = -EINVAL;
         int has_write_lock = 0;
+        vm_flags_t vm_flags;
 
         if (prot)
                 return err;
@@ -228,30 +229,16 @@ get_write_lock:
                 /*
                  * drop PG_Mlocked flag for over-mapped range
                  */
-                vm_flags_t saved_flags = vma->vm_flags;
                 if (!has_write_lock)
                         goto get_write_lock;
+                vm_flags = vma->vm_flags;
                 munlock_vma_pages_range(vma, start, start + size);
-                vma->vm_flags = saved_flags;
+                vma->vm_flags = vm_flags;
         }
 
         mmu_notifier_invalidate_range_start(mm, start, start + size);
         err = vma->vm_ops->remap_pages(vma, start, size, pgoff);
         mmu_notifier_invalidate_range_end(mm, start, start + size);
-        if (!err) {
-                if (vma->vm_flags & VM_LOCKED) {
-                        /*
-                         * might be mapping previously unmapped range of file
-                         */
-                        mlock_vma_pages_range(vma, start, start + size);
-                } else if (!(flags & MAP_NONBLOCK)) {
-                        if (unlikely(has_write_lock)) {
-                                downgrade_write(&mm->mmap_sem);
-                                has_write_lock = 0;
-                        }
-                        make_pages_present(start, start+size);
-                }
-        }
 
         /*
          * We can't clear VM_NONLINEAR because we'd have to do
@@ -260,10 +247,13 @@ get_write_lock:
          */
 
 out:
+        vm_flags = vma->vm_flags;
         if (likely(!has_write_lock))
                 up_read(&mm->mmap_sem);
         else
                 up_write(&mm->mmap_sem);
+        if (!err && ((vm_flags & VM_LOCKED) || !(flags & MAP_NONBLOCK)))
+                mm_populate(start, size);
 
         return err;
 }