From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753545AbbCITeu (ORCPT ); Mon, 9 Mar 2015 15:34:50 -0400 Received: from mout.kundenserver.de ([212.227.17.10]:56634 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752426AbbCITet (ORCPT ); Mon, 9 Mar 2015 15:34:49 -0400 From: Arnd Bergmann To: David Woodhouse , Brian Norris Cc: Ezequiel Garcia , Jingoo Han , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] MTD: cfi: reduce stack size Date: Mon, 09 Mar 2015 20:34:19 +0100 Message-ID: <2376719.UMjvd0rdnO@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:SSzTfLOv8cX2jvV58g7DInp6XFv+SSD7pUOahF1SwFMAP57hi8F woiPtdVqlZhdTCTCwtjRUCbMjpFbhZx+CUokcFox1frY+AM2hAP177JeXsda736yzQHZbQq Lq2136DlTD5i2sDZlpBjmFpn4PIV13eyjnbBaAVB8A2l1ujvXR+rdVIRlDweGJcZu4LZHKp isSZ8mCltsZTTZseusqxQ== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The cfi_staa_write_buffers function uses a large amount of kernel stack 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..7b5841663d4f 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 < map_words(map); i++) { + if ((val1.x[i] & val2.x[i]) != val3.x[i]) + return 0; + } + return 1; +} static inline int map_word_bitsset(struct map_info *map, map_word val1, map_word val2) {