From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753570AbbCJQtR (ORCPT ); Tue, 10 Mar 2015 12:49:17 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:58136 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753324AbbCJQtH (ORCPT ); Tue, 10 Mar 2015 12:49:07 -0400 From: Arnd Bergmann To: David Woodhouse , Brian Norris Cc: Jingoo Han , linux-mtd@lists.infradead.org, Ezequiel Garcia , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] mtd: cfi: reduce stack size Date: Tue, 10 Mar 2015 17:48:37 +0100 Message-ID: <2266200.3mx7btcFe5@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:K0:0LVeVaVC3PvbiMfAHWxe1NOn2HpFSsyu3nTkpQYWrV240dWBaMf 78DmYZfyVoLH3EYu2SCfNiWwXVu+FmK6/vJOc8dNOr3Go5uXh2bzRrlNrm76c0C1NjPI/5i m371wy5Q/XHh01DmjudW8gZbdJITAvU8PQuIw0MtzHyMVKTX0ZZzRFyhPn5qRr5h1ff1Vkq V3l5M1sOTxZAWc/mILiwA== 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 --- v3: more whitespace changes v2: whitespace changes diff --git a/include/linux/mtd/map.h b/include/linux/mtd/map.h index 47c59991491b..29975c73a953 100644 --- a/include/linux/mtd/map.h +++ b/include/linux/mtd/map.h @@ -316,7 +316,17 @@ 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) {