From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757065AbYGaPqR (ORCPT ); Thu, 31 Jul 2008 11:46:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751658AbYGaPqE (ORCPT ); Thu, 31 Jul 2008 11:46:04 -0400 Received: from vpn.id2.novell.com ([195.33.99.129]:37779 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752094AbYGaPqD convert rfc822-to-8bit (ORCPT ); Thu, 31 Jul 2008 11:46:03 -0400 Message-Id: <4891FA82.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 7.0.3 Date: Thu, 31 Jul 2008 16:46:42 +0100 From: "Jan Beulich" To: Cc: "Ingo Molnar" , , Subject: [PATCH] fix order calculation in dma_mark_declared_memory_occupied() Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org get_order() takes byte-sized input, not a page-granular one. Irrespective of this fix I'm inclined to believe that this doesn't work right anyway - bitmap_allocate_region() has an implicit assumption of 'pos' being suitable for 'order', which this function doesn't seem to enforce (and since it's being called with a byte-granular value there's no reason to believe that the callers would make sure device_addr is passed accordingly - it's also not documented that way). Signed-off-by: Jan Beulich Cc: James E.J. Bottomley Cc: Ingo Molnar Cc: Dmitry Baryshkov --- kernel/dma-coherent.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- linux-2.6.27-rc1/kernel/dma-coherent.c 2008-07-31 17:08:36.000000000 +0200 +++ 2.6.27-rc1-dma-mark-declared/kernel/dma-coherent.c 2008-07-31 14:35:59.000000000 +0200 @@ -77,15 +77,14 @@ void *dma_mark_declared_memory_occupied( { struct dma_coherent_mem *mem = dev->dma_mem; int pos, err; - int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1); - pages >>= PAGE_SHIFT; + size += device_addr & ~PAGE_MASK; if (!mem) return ERR_PTR(-EINVAL); pos = (device_addr - mem->device_base) >> PAGE_SHIFT; - err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages)); + err = bitmap_allocate_region(mem->bitmap, pos, get_order(size)); if (err != 0) return ERR_PTR(err); return mem->virt_base + (pos << PAGE_SHIFT);