From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755728AbdEKNDg (ORCPT ); Thu, 11 May 2017 09:03:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50518 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755703AbdEKNDe (ORCPT ); Thu, 11 May 2017 09:03:34 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Brian Norris Subject: [PATCH 3.18 03/39] mtd: cfi: reduce stack size Date: Thu, 11 May 2017 15:02:38 +0200 Message-Id: <20170511130238.758833412@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170511130238.045434679@linuxfoundation.org> References: <20170511130238.045434679@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit d09957fbb4d0b059b3176b510540df69048ad170 upstream. 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 Signed-off-by: Brian Norris Signed-off-by: Greg Kroah-Hartman --- include/linux/mtd/map.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/include/linux/mtd/map.h +++ b/include/linux/mtd/map.h @@ -309,7 +309,17 @@ static inline map_word map_word_or(struc 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) {