Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753573AbaKXPBd (ORCPT ); Mon, 24 Nov 2014 10:01:33 -0500 Received: from mail-wg0-f52.google.com ([74.125.82.52]:52544 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751069AbaKXPBb (ORCPT ); Mon, 24 Nov 2014 10:01:31 -0500 Message-ID: <54734844.1070505@linaro.org> Date: Mon, 24 Nov 2014 16:01:24 +0100 From: Tomasz Nowicki User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Hanjun Guo , Catalin Marinas , Mark Rutland , Olof Johansson , Grant Likely , Will Deacon , Graeme Gregory , Arnd Bergmann , Sudeep Holla , Jon Masters , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Lv Zheng , Robert Moore , Lorenzo Pieralisi , Liviu Dudau , Randy Dunlap , Charles.Garcia-Tobin@arm.com, Kangkang.Shen@huawei.com, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org Subject: Re: [PATCH v5 03/18] ACPI / table: Count matched and successfully parsed entries without specifying max entries References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <6619034.gHDuQJ1A7y@vostro.rjw.lan> <5472ED90.5010803@linaro.org> <2301926.MWJ5MneAen@vostro.rjw.lan> In-Reply-To: <2301926.MWJ5MneAen@vostro.rjw.lan> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24.11.2014 16:16, Rafael J. Wysocki wrote: > On Monday, November 24, 2014 09:34:24 AM Tomasz Nowicki wrote: >> On 24.11.2014 02:45, Rafael J. Wysocki wrote: >>> On Friday, October 17, 2014 09:36:59 PM Hanjun Guo wrote: >>>> From: Tomasz Nowicki >>>> >>>> It is very useful to traverse all available table entries without max >>>> number of expected entries type. Current acpi_parse_entries() >>>> implementation gives that feature but it does not count those entries, >>>> it returns 0 instead, so fix it to count matched and successfully >>>> entries and return it. >>> >>> Hmm. I guess that the goal is for count to only be incremented when the >>> condition is satisfied entirely, while without the patch it may be incremented >>> even if that isn't the case. >> >> That would be our goal if patch would look like: >> - && (!max_entries || count++ < max_entries)) >> + && (!max_entries && count++ < max_entries)) { >> but then we can not walk through all available entries (with max_entries==0) > > No, that's not what I was trying to say. :-) > >>> >>> I'm not sure how that is related to the above paragraph, however. >>> >> >> Previous changelog is not clear, let me rewrite it: >> >> acpi_parse_entries() allows to traverse all available table entries (aka >> subtables) by passing max_entries parameter equal to 0. But for that use >> case acpi_parse_entries() does not inform caller how many entries were >> matched and for how many entries handler was run against. That patch is >> going to fix it. > > Do I understand correctly that count is only ever incremented by current code > if max_entries is different from 0? Right. Currently "count" is incremented only if max_entries > 0. Tomasz > > >>>> NOTE: This change has no impact to x86 and ia64 archs since existing code >>>> checks for error occurrence only (acpi_parse_entries(...,0) < 0). >>>> >>>> Acked-by: Grant Likely >>>> Signed-off-by: Tomasz Nowicki >>>> Signed-off-by: Hanjun Guo >>>> --- >>>> drivers/acpi/tables.c | 5 ++++- >>>> 1 file changed, 4 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c >>>> index 21ae521..b18e45e 100644 >>>> --- a/drivers/acpi/tables.c >>>> +++ b/drivers/acpi/tables.c >>>> @@ -225,10 +225,13 @@ acpi_parse_entries(unsigned long table_size, >>>> while (((unsigned long)entry) + sizeof(struct acpi_subtable_header) < >>>> table_end) { >>>> if (entry->type == entry_id >>>> - && (!max_entries || count++ < max_entries)) >>>> + && (!max_entries || count < max_entries)) { >>>> if (handler(entry, table_end)) >>>> return -EINVAL; >>>> >>>> + count++; >>>> + } >>>> + >>>> /* >>>> * If entry->length is 0, break from this loop to avoid >>>> * infinite loop. >>>> >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- 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/