Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760063AbYGRMbK (ORCPT ); Fri, 18 Jul 2008 08:31:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759671AbYGRMap (ORCPT ); Fri, 18 Jul 2008 08:30:45 -0400 Received: from smtp.ustc.edu.cn ([202.38.64.16]:34037 "HELO ustc.edu.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1759610AbYGRMap (ORCPT ); Fri, 18 Jul 2008 08:30:45 -0400 Message-ID: <416384276.24780@ustc.edu.cn> X-WebMAIL-MUA: [211.86.158.24] From: "JiSheng Zhang" To: stefanr@s5r6.in-berlin.de Cc: linux-kernel@vger.kernel.org, linux1394-devel@lists.sourceforge.net, krh@redhat.com Date: Fri, 18 Jul 2008 20:31:16 +0800 Reply-To: "JiSheng Zhang" X-Priority: 3 Subject: Re: PATCH] firewire: add padding to some struct Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2110 Lines: 59 Hi, >From: Stefan Richter >Reply-To: >To: JiSheng Zhang >Subject: Re: PATCH] firewire: add padding to some struct >Date:Fri, 18 Jul 2008 13:38:25 +0200 > >JiSheng Zhang wrote: > > If p is a pointer to struct fw_cdev_event_response), p->data will point to the > > padding data rather than the right place, it will cause problem under some > > platforms. For example, in the function handle_device_event of libraw1394(ported > > to juju stack): > > ..... > > case FW_CDEV_EVENT_RESPONSE: > > rc = u64_to_ptr(u->response.closure); > > if (rc->data != NULL) > > memcpy(rc->data, u->response.data, rc->length);//here it will lost the last four > > bytes > > errcode = juju_to_raw1394_errcode(u->response.rcode); > > ..... > > > > Although this problem can be solved by add the offset to the pointer, but the > > member:__u32 data[0] lost its original meaning. > > I don't understand what the problem is. As long as both kernel and > library use "response.data" or "&response + offsetof(typeof(response), > data)", they will write and read at the correct location. > This patch can fix the problem while not changing the struct definition. Thanks in advance, JiSheng --- old/drivers/firewire/fw-cdev.c 2008-07-14 05:51:29.000000000 +0800 +++ new/drivers/firewire/fw-cdev.c 2008-07-18 20:20:45.841328585 +0800 @@ -382,9 +382,9 @@ response->response.type = FW_CDEV_EVENT_RESPONSE; response->response.rcode = rcode; - queue_event(client, &response->event, - &response->response, sizeof(response->response), - response->response.data, response->response.length); + queue_event(client, &response->event, &response->response, + sizeof(response->response) + response->response.length, + NULL, 0); } static int ioctl_send_request(struct client *client, void *buffer) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/