From patchwork Fri Dec 7 13:03:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 53377 Received: from vger.kernel.org ([209.132.180.67]) by www.linuxtv.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gVFmt-0003zZ-9d; Fri, 07 Dec 2018 13:03:24 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726136AbeLGNDV (ORCPT + 1 other); Fri, 7 Dec 2018 08:03:21 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:59836 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726011AbeLGNDV (ORCPT ); Fri, 7 Dec 2018 08:03:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=irp9Q0vFaW5yDtwk3V9gSBSYVDjzI6i8ovMgXYUQUbo=; b=UOgGPNbSk06rTYHXc2qEqU5K1 U9c8kJrra31HxQDWF30d5j+5AFC5lWm72Bik+DWLbYR63UZ1sSdskykhd4rXwnfyzNkbXgopsnIGT ms6kiA/bHaREkKr/izMvuyeKnVXCPrPf7xShwtSJ3q08CIm1WXm6BhHNVvVHhTK35pNdApyDbCeqH W45C2vtriRs7+I+cQnX/lEEwmjZuELb0I1RYmuuINkueovJV8V9gg4Kz2arDpzNna5QOlvOn9ETF7 h97aXlz33j6igA1gaHYYk7VLoGLBUbqN/nVMTkhMJH+dnsokcUSwiPpvLGfpQtT1LhFIbl6Q6TNfB 20ru8uxVQ==; Received: from 201.86.173.17.dynamic.adsl.gvt.net.br ([201.86.173.17] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVFmq-0001PA-O6; Fri, 07 Dec 2018 13:03:20 +0000 Received: from mchehab by bombadil.infradead.org with local (Exim 4.91) (envelope-from ) id 1gVFmn-000120-N2; Fri, 07 Dec 2018 08:03:17 -0500 From: Mauro Carvalho Chehab Cc: Mauro Carvalho Chehab , Linux Media Mailing List , Mauro Carvalho Chehab , Maxime Ripard , Paul Kocialkowski , Greg Kroah-Hartman , Chen-Yu Tsai , devel@driverdev.osuosl.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] media: cedrus: don't initialize pointers with zero Date: Fri, 7 Dec 2018 08:03:16 -0500 Message-Id: <9db60f061d1c577f14136f81af641f58bccbead3.1544187795.git.mchehab+samsung@kernel.org> X-Mailer: git-send-email 2.19.2 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org A common mistake is to assume that initializing a var with: struct foo f = { 0 }; Would initialize a zeroed struct. Actually, what this does is to initialize the first element of the struct to zero. According to C99 Standard 6.7.8.21: "If there are fewer initializers in a brace-enclosed list than there are elements or members of an aggregate, or fewer characters in a string literal used to initialize an array of known size than there are elements in the array, the remainder of the aggregate shall be initialized implicitly the same as objects that have static storage duration." So, in practice, it could zero the entire struct, but, if the first element is not an integer, it will produce warnings: drivers/staging/media/sunxi/cedrus/cedrus.c:drivers/staging/media/sunxi/cedrus/cedrus.c:78:49: warning: Using plain integer as NULL pointer drivers/staging/media/sunxi/cedrus/cedrus_dec.c:drivers/staging/media/sunxi/cedrus/cedrus_dec.c:29:35: warning: Using plain integer as NULL pointer As the right initialization would be, instead: struct foo f = { NULL }; Another way to initialize it with gcc is to use: struct foo f = {}; That seems to be a gcc extension, but clang also does the right thing, and that's a clean way for doing it. Anyway, I decided to check upstream what's the most commonly pattern. The "= {}" pattern has about 2000 entries: $ git grep -E "=\s*\{\s*\}"|wc -l 1951 The standard-C compliant pattern has about 2500 entries: $ git grep -E "=\s*\{\s*NULL\s*\}"|wc -l 137 $ git grep -E "=\s*\{\s*0\s*\}"|wc -l 2323 Meaning that developers have split options on that. So, let's opt to the simpler form. Signed-off-by: Mauro Carvalho Chehab Acked-by: Paul Kocialkowski --- drivers/staging/media/sunxi/cedrus/cedrus.c | 2 +- drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c index b538eb0321d8..b7c918fa5fd1 100644 --- a/drivers/staging/media/sunxi/cedrus/cedrus.c +++ b/drivers/staging/media/sunxi/cedrus/cedrus.c @@ -75,7 +75,7 @@ static int cedrus_init_ctrls(struct cedrus_dev *dev, struct cedrus_ctx *ctx) memset(ctx->ctrls, 0, ctrl_size); for (i = 0; i < CEDRUS_CONTROLS_COUNT; i++) { - struct v4l2_ctrl_config cfg = { 0 }; + struct v4l2_ctrl_config cfg = {}; cfg.elem_size = cedrus_controls[i].elem_size; cfg.id = cedrus_controls[i].id; diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c index e40180a33951..f10c25f5460e 100644 --- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c +++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c @@ -26,7 +26,7 @@ void cedrus_device_run(void *priv) { struct cedrus_ctx *ctx = priv; struct cedrus_dev *dev = ctx->dev; - struct cedrus_run run = { 0 }; + struct cedrus_run run = {}; struct media_request *src_req; unsigned long flags;