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>
diff --git a/mm/mlock.c b/mm/mlock.c
index a296a49..569400a 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -155,9 +155,8 @@
*
* vma->vm_mm->mmap_sem must be held for at least read.
*/
-static long __mlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end,
- int *nonblocking)
+long __mlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end, int *nonblocking)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long addr = start;
@@ -202,56 +201,6 @@
return retval;
}
-/**
- * mlock_vma_pages_range() - mlock pages in specified vma range.
- * @vma - the vma containing the specfied address range
- * @start - starting address in @vma to mlock
- * @end - end address [+1] in @vma to mlock
- *
- * For mmap()/mremap()/expansion of mlocked vma.
- *
- * return 0 on success for "normal" vmas.
- *
- * return number of pages [> 0] to be removed from locked_vm on success
- * of "special" vmas.
- */
-long mlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end)
-{
- int nr_pages = (end - start) / PAGE_SIZE;
- BUG_ON(!(vma->vm_flags & VM_LOCKED));
-
- /*
- * filter unlockable vmas
- */
- if (vma->vm_flags & (VM_IO | VM_PFNMAP))
- goto no_mlock;
-
- if (!((vma->vm_flags & VM_DONTEXPAND) ||
- is_vm_hugetlb_page(vma) ||
- vma == get_gate_vma(current->mm))) {
-
- __mlock_vma_pages_range(vma, start, end, NULL);
-
- /* Hide errors from mmap() and other callers */
- return 0;
- }
-
- /*
- * User mapped kernel pages or huge pages:
- * make these pages present to populate the ptes, but
- * fall thru' to reset VM_LOCKED--no need to unlock, and
- * return nr_pages so these don't get counted against task's
- * locked limit. huge pages are already counted against
- * locked vm limit.
- */
- make_pages_present(start, end);
-
-no_mlock:
- vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */
- return nr_pages; /* error or pages NOT mlocked */
-}
-
/*
* munlock_vma_pages_range() - munlock all pages in the vma range.'
* @vma - vma containing range to be munlock()ed.
@@ -303,7 +252,7 @@
*
* Filters out "special" vmas -- VM_LOCKED never gets set for these, and
* munlock is a no-op. However, for some special vmas, we go ahead and
- * populate the ptes via make_pages_present().
+ * populate the ptes.
*
* For vmas that pass the filters, merge/split as appropriate.
*/