mm/mmap: Use vms accounted pages in mmap_region()

Change from nr_pages variable to vms.nr_accounted for the charged pages
calculation.  This is necessary for a future patch.

This also avoids checking security_vm_enough_memory_mm() if the amount
of memory won't change.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Kees Cook <kees@kernel.org>
Cc: linux-security-module@vger.kernel.org
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Paul Moore <paul@paul-moore.com> (LSM)

diff --git a/mm/mmap.c b/mm/mmap.c
index f8515126e4357924746588ca1b69fc98c59b32a1..aa4aa49f3b97d3e59a8c2944d28aa54b56cf1a89 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1413,9 +1413,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
         */
        if (accountable_mapping(file, vm_flags)) {
                charged = pglen;
-               charged -= nr_accounted;
-               if (security_vm_enough_memory_mm(mm, charged))
+               charged -= vms.nr_accounted;
+               if (charged && security_vm_enough_memory_mm(mm, charged))
                        goto abort_munmap;
+
                vms.nr_accounted = 0;
                vm_flags |= VM_ACCOUNT;
        }