[PATCH] mm: exit_mmap need not reset

exit_mmap resets various mm_struct fields, but the mm is well on its way out,
and none of those fields matter by this point.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

mm/mmap.c

@@ -1948,12 +1948,6 @@ void exit_mmap(struct mm_struct *mm)
 	free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
 	tlb_finish_mmu(tlb, 0, end);
 
-	mm->mmap = mm->mmap_cache = NULL;
-	mm->mm_rb = RB_ROOT;
-	set_mm_counter(mm, rss, 0);
-	mm->total_vm = 0;
-	mm->locked_vm = 0;
-
 	spin_unlock(&mm->page_table_lock);
 
 	/*