From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933292AbcBAOzr (ORCPT ); Mon, 1 Feb 2016 09:55:47 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:48854 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932797AbcBAOzp (ORCPT ); Mon, 1 Feb 2016 09:55:45 -0500 Date: Mon, 1 Feb 2016 14:54:57 +0000 From: One Thousand Gnomes To: Arnd Bergmann Cc: gregkh@linuxfoundation.org, Greg Hackmann , Jin Qian , Alan Cox , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] staging: goldfish: use div64_s64 instead of do_div Message-ID: <20160201145457.7879d53f@lxorguk.ukuu.org.uk> In-Reply-To: <1676170.0qik6mzm6D@wuerfel> References: <1676170.0qik6mzm6D@wuerfel> Organization: Intel Corporation X-Mailer: Claws Mail 3.13.1 (GTK+ 2.24.29; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 01 Feb 2016 11:33 +0100 Arnd Bergmann wrote: > The goldfish nand driver divides a signed 64-bit number (loff_t) > in multiple places using the do_div() function. This has always > been unreliable but now produces a compiler warning (since 4.5-rc1): > > goldfish/goldfish_nand.c: In function 'goldfish_nand_erase': > goldfish/goldfish_nand.c:107:91: error: comparison of distinct pointer types lacks a cast [-Werror] > goldfish/goldfish_nand.c: In function 'goldfish_nand_read_oob': > goldfish/goldfish_nand.c:145:91: error: comparison of distinct pointer types lacks a cast [-Werror] > > This changes the code to the equivalent div_s64{,_rem} that > works correctly for negative numbers (which we should never > get here). We can't get negatives as you say so surely the right fix is a cast or to fix mtd->writesize ?