mm: __tlb_remove_page() check the correct batch

__tlb_remove_page() switches to a new batch page, but still checks space
in the old batch.  This check always fails, and causes a forced tlb flush.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

@@ -305,6 +305,7 @@ int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 	if (batch->nr == batch->max) {
 		if (!tlb_next_batch(tlb))
 			return 0;
+		batch = tlb->active;
 	}
 	VM_BUG_ON(batch->nr > batch->max);