From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753210AbbCITeT (ORCPT ); Mon, 9 Mar 2015 15:34:19 -0400 Received: from mout.kundenserver.de ([212.227.17.10]:60140 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751931AbbCITeS (ORCPT ); Mon, 9 Mar 2015 15:34:18 -0400 From: Arnd Bergmann To: Ezequiel Garcia Cc: David Woodhouse , Brian Norris , Jingoo Han , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] MTD: cfi: reduce stack size Date: Mon, 09 Mar 2015 20:33:17 +0100 Message-ID: <10197110.03snLubgYs@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <54FDC33E.2060004@vanguardiasur.com.ar> References: <2161999.Fy9EjgoTPm@wuerfel> <54FDC33E.2060004@vanguardiasur.com.ar> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:5UNKiz2tFMy0cFQzwX+ti/GUkLkfdsCzrAFL0sNnsNWaIdvna05 VJ5bEHJGfPipnqcXGp5K3vRHrL2boNodMxhG+sg8Jf1f6beM6oC22+9KHlg+voJMCzkZgm9 yEYrfdIpSVDBLEWbLzmwG4A/FyqlIVe0jcSa8HAp1oMIJbz7XqxU5iV6AG2cQB8BBu+9lxK UP/4nI+MlFcRha54WkK7A== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 09 March 2015 12:58:54 Ezequiel Garcia wrote: > On 03/09/2015 10:58 AM, Arnd Bergmann wrote: > > The cfi_staa_write_buffers function uses a large amount of ernel stack > > Typo: "ernel" ok > > whenever CONFIG_MTD_MAP_BANK_WIDTH_32 is set, and that results in a > > warning on ARM allmodconfig builds: > > > > drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_write_buffers': > > drivers/mtd/chips/cfi_cmdset_0020.c:651:1: warning: the frame size of 1208 bytes is larger than 1024 bytes [-Wframe-larger-than=] > > > > It turns out that this is largely a result of a suboptimal implementation > > of map_word_andequal(). Replacing this function with a straightforward > > one reduces the stack size in this function by exactly 200 bytes, > > shrinks the .text segment for this file from 27648 bytes to 26608 bytes, > > and makes the warning go away. > > > > Signed-off-by: Arnd Bergmann > > > > diff --git a/include/linux/mtd/map.h b/include/linux/mtd/map.h > > index 5f487d776411..2d2457bee50c 100644 > > --- a/include/linux/mtd/map.h > > +++ b/include/linux/mtd/map.h > > @@ -314,7 +314,15 @@ static inline map_word map_word_or(struct map_info *map, map_word val1, map_word > > return r; > > } > > > > -#define map_word_andequal(m, a, b, z) map_word_equal(m, z, map_word_and(m, a, b)) > > +static inline int map_word_andequal(struct map_info *map, map_word val1, map_word val2, map_word val3) > > +{ > > + int i; > > + for (i=0; i > Nit: > > for (i = 0; i < map_words(map); i++) It's the same as five other copies of the same loop in this file, but I've changed this one now. Thanks, Arnd