Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754616AbbLKJKr (ORCPT ); Fri, 11 Dec 2015 04:10:47 -0500 Received: from mail-wm0-f41.google.com ([74.125.82.41]:33038 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814AbbLKJKh (ORCPT ); Fri, 11 Dec 2015 04:10:37 -0500 MIME-Version: 1.0 In-Reply-To: <87mvthcqrm.fsf@ashishki-desk.ger.corp.intel.com> References: <1449804410-16833-1-git-send-email-zhang.chunyan@linaro.org> <87mvthxwzb.fsf@ashishki-desk.ger.corp.intel.com> <87mvthcqrm.fsf@ashishki-desk.ger.corp.intel.com> Date: Fri, 11 Dec 2015 17:10:36 +0800 Message-ID: Subject: Re: [PATCH] stm: the number of masters should be (sw_end - sw_start + 1) From: Chunyan Zhang To: Alexander Shishkin Cc: "linux-kernel@vger.kernel.org" , Mathieu Poirier Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2772 Lines: 69 On Fri, Dec 11, 2015 at 4:51 PM, Alexander Shishkin wrote: > Chunyan Zhang writes: > >> On Fri, Dec 11, 2015 at 3:31 PM, Alexander Shishkin >> wrote: >>> Chunyan Zhang writes: >>> >>>> sw_end represents the last software master, sw_start is index of the >>>> first master, so the number of software masters should be >>>> sw_end - sw_start + 1. >>> >>> Looks about right, but it needs to be in two separate patches. >>> >>>> Signed-off-by: Chunyan Zhang >>>> --- >>>> drivers/hwtracing/intel_th/sth.c | 2 +- >>>> drivers/hwtracing/stm/core.c | 2 +- >>>> 2 files changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/hwtracing/intel_th/sth.c b/drivers/hwtracing/intel_th/sth.c >>>> index 56101c3..28917d7 100644 >>>> --- a/drivers/hwtracing/intel_th/sth.c >>>> +++ b/drivers/hwtracing/intel_th/sth.c >>>> @@ -173,7 +173,7 @@ static int intel_th_sw_init(struct sth_device *sth) >>>> sth->stm.sw_start = reg & 0xffff; >>>> sth->stm.sw_end = reg >> 16; >>>> >>>> - sth->sw_nmasters = sth->stm.sw_end - sth->stm.sw_start; >>>> + sth->sw_nmasters = sth->stm.sw_end - sth->stm.sw_start + 1; >>>> dev_dbg(sth->dev, "sw_start: %x sw_end: %x masters: %x nchannels: %x\n", >>>> sth->stm.sw_start, sth->stm.sw_end, sth->sw_nmasters, >>>> sth->stm.sw_nchannels); >>>> diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c >>>> index 7f7bdb3..cb676f2 100644 >>>> --- a/drivers/hwtracing/stm/core.c >>>> +++ b/drivers/hwtracing/stm/core.c >>>> @@ -632,7 +632,7 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data, >>>> if (!stm_data->packet || !stm_data->sw_nchannels) >>>> return -EINVAL; >>>> >>>> - nmasters = stm_data->sw_end - stm_data->sw_start; >>>> + nmasters = stm_data->sw_end - stm_data->sw_start + 1; >>>> stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); >>> >>> Or even offsetof(struct stm_device, masters[stm_data->sw_end]). >>> >> >> This should use 'offsetofend()'. > > No, actually, just scratch my previous comment as it was completely > wrong, just fix the off-by-one. If we were to use offsetof(), it should > rather be of masters[nmasters], but all we need is to fix the off-by-one > right now. > Sorry, you may lose me here, what's 'off-by-one' ? Thanks, Chunyan > Regards, > -- > Alex -- 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/