From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x242.google.com (mail-lf0-x242.google.com [IPv6:2a00:1450:4010:c07::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3syxSH4k7CzDt2P for ; Wed, 19 Oct 2016 00:56:15 +1100 (AEDT) Received: by mail-lf0-x242.google.com with SMTP id x79so32890045lff.2 for ; Tue, 18 Oct 2016 06:56:15 -0700 (PDT) Date: Tue, 18 Oct 2016 14:56:09 +0100 From: Lorenzo Stoakes To: Jan Kara Cc: linux-mm@kvack.org, Linus Torvalds , Hugh Dickins , Dave Hansen , Rik van Riel , Mel Gorman , Andrew Morton , adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cris-kernel@axis.com, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@linux-mips.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags Message-ID: <20161018135609.GA30025@lucifer> References: <20161013002020.3062-1-lstoakes@gmail.com> <20161013002020.3062-5-lstoakes@gmail.com> <20161018125425.GD29967@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20161018125425.GD29967@quack2.suse.cz> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Oct 18, 2016 at 02:54:25PM +0200, Jan Kara wrote: > > @@ -1282,7 +1282,7 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, > > int write, int force, struct page **pages, > > struct vm_area_struct **vmas); > > long get_user_pages_locked(unsigned long start, unsigned long nr_pages, > > - int write, int force, struct page **pages, int *locked); > > + unsigned int gup_flags, struct page **pages, int *locked); > > Hum, the prototype is inconsistent with e.g. __get_user_pages_unlocked() > where gup_flags come after **pages argument. Actually it makes more sense > to have it before **pages so that input arguments come first and output > arguments second but I don't care that much. But it definitely should be > consistent... It was difficult to decide quite how to arrange parameters as there was inconsitency with regards to parameter ordering already - for example __get_user_pages() places its flags argument before pages whereas, as you note, __get_user_pages_unlocked() puts them afterwards. I ended up compromising by trying to match the existing ordering of the function as much as I could by replacing write, force pairs with gup_flags in the same location (with the exception of get_user_pages_unlocked() which I felt should match __get_user_pages_unlocked() in signature) or if there was already a gup_flags parameter as in the case of __get_user_pages_unlocked() I simply removed the write, force pair and left the flags as the last parameter. I am happy to rearrange parameters as needed, however I am not sure if it'd be worthwhile for me to do so (I am keen to try to avoid adding too much noise here :) If we were to rearrange parameters for consistency I'd suggest adjusting __get_user_pages_unlocked() to put gup_flags before pages and do the same with get_user_pages_unlocked(), let me know what you think.