mm: directly use __mlock_vma_pages_range() in find_extend_vma()

In find_extend_vma(), we don't need mlock_vma_pages_range() to verify
the vma type - we know we're working with a stack.  So, we can call
directly into __mlock_vma_pages_range(), and remove the last
make_pages_present() call site.

Note that we don't use mm_populate() here, so we can't release the
mmap_sem while allocating new stack pages.  This is deemed acceptable,
because the stack vmas grow by a bounded number of pages at a time, and
these are anon pages so we don't have to read from disk to populate
them.

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-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, 4 insertions, 6 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index d6bc39e939ab..8826c77513a9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2204,9 +2204,8 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
                 return vma;
         if (!prev || expand_stack(prev, addr))
                 return NULL;
-        if (prev->vm_flags & VM_LOCKED) {
-                mlock_vma_pages_range(prev, addr, prev->vm_end);
-        }
+        if (prev->vm_flags & VM_LOCKED)
+                __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL);
         return prev;
 }
 #else
@@ -2232,9 +2231,8 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr)
         start = vma->vm_start;
         if (expand_stack(vma, addr))
                 return NULL;
-        if (vma->vm_flags & VM_LOCKED) {
-                mlock_vma_pages_range(vma, addr, start);
-        }
+        if (vma->vm_flags & VM_LOCKED)
+                __mlock_vma_pages_range(vma, addr, start, NULL);
         return vma;
 }
 #endif