mm: don't rely on flags coincidence

[linux.git] / mm / madvise.c

diff --git a/mm/madvise.c b/mm/madvise.c
index b9ce574827c8a2a48b972f0261decc234edf9e27..76eb4193acddb2e739b1e42a0a8371b59464f39f 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -123,8 +123,7 @@ static long madvise_willneed(struct vm_area_struct * vma,
                end = vma->vm_end;
        end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
 
-       force_page_cache_readahead(file->f_mapping,
-                       file, start, max_sane_readahead(end - start));
+       force_page_cache_readahead(file->f_mapping, file, start, end - start);
        return 0;
 }
 
@@ -239,12 +238,30 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
                break;
 
        default:
-               error = -EINVAL;
+               BUG();
                break;
        }
        return error;
 }
 
+static int
+madvise_behavior_valid(int behavior)
+{
+       switch (behavior) {
+       case MADV_DOFORK:
+       case MADV_DONTFORK:
+       case MADV_NORMAL:
+       case MADV_SEQUENTIAL:
+       case MADV_RANDOM:
+       case MADV_REMOVE:
+       case MADV_WILLNEED:
+       case MADV_DONTNEED:
+               return 1;
+
+       default:
+               return 0;
+       }
+}
 /*
  * The madvise(2) system call.
  *
@@ -290,6 +307,9 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
        int write;
        size_t len;
 
+       if (!madvise_behavior_valid(behavior))
+               return error;
+
        write = madvise_need_mmap_write(behavior);
        if (write)
                down_write(&current->mm->mmap_sem);