Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934298AbdGKWPo (ORCPT ); Tue, 11 Jul 2017 18:15:44 -0400 Received: from gateway34.websitewelcome.com ([192.185.148.164]:45406 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932870AbdGKWPm (ORCPT ); Tue, 11 Jul 2017 18:15:42 -0400 Date: Tue, 11 Jul 2017 17:15:38 -0500 From: "Gustavo A. R. Silva" To: Thor Thayer , Linus Walleij Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] gpio: altera-a10sr: constify gpio_chip structure Message-ID: <20170711221538.GA8001@embeddedgus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.152.228.197 X-Exim-ID: 1dV3RU-002MO7-18 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedgus) [189.152.228.197]:58758 X-Source-Auth: garsilva@embeddedor.com X-Email-Count: 4 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1604 Lines: 64 This structure is only used to copy into another structure, so declare it as const. This issue was detected using Coccinelle and the following semantic patch: @r disable optional_qualifier@ identifier i; position p; @@ static struct gpio_chip i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p; @bad@ position p != {r.p,ok.p}; identifier r.i; struct gpio_chip e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct gpio_chip i = { ... }; In the following log you can see a significant difference in the code size and data segment, hence in the dec segment. This log is the output of the size command, before and after the code change: before: text data bss dec hex filename 1954 600 0 2554 9fa drivers/gpio/gpio-altera-a10sr.o after: text data bss dec hex filename 1655 512 0 2167 877 drivers/gpio/gpio-altera-a10sr.o Signed-off-by: Gustavo A. R. Silva --- drivers/gpio/gpio-altera-a10sr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-altera-a10sr.c b/drivers/gpio/gpio-altera-a10sr.c index 16a8951..6b11f13 100644 --- a/drivers/gpio/gpio-altera-a10sr.c +++ b/drivers/gpio/gpio-altera-a10sr.c @@ -71,7 +71,7 @@ static int altr_a10sr_gpio_direction_output(struct gpio_chip *gc, return -EINVAL; } -static struct gpio_chip altr_a10sr_gc = { +static const struct gpio_chip altr_a10sr_gc = { .label = "altr_a10sr_gpio", .owner = THIS_MODULE, .get = altr_a10sr_gpio_get, -- 2.5.0