Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760293AbaKATVT (ORCPT ); Sat, 1 Nov 2014 15:21:19 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:55222 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759209AbaKATVQ (ORCPT ); Sat, 1 Nov 2014 15:21:16 -0400 Date: Sat, 01 Nov 2014 15:21:12 -0400 (EDT) Message-Id: <20141101.152112.741323581543029110.davem@davemloft.net> To: aneesh.kumar@linux.vnet.ibm.com Cc: akpm@linux-foundation.org, steve.capper@linaro.org, aarcange@redhat.com, benh@kernel.crashing.org, mpe@ellerman.id.au, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org Subject: Re: [PATCH V4 1/2] mm: Update generic gup implementation to handle hugepage directory From: David Miller In-Reply-To: <1414570785-18966-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1414570785-18966-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.7 (shards.monkeyblade.net [149.20.54.216]); Sat, 01 Nov 2014 12:21:15 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Aneesh Kumar K.V" Date: Wed, 29 Oct 2014 13:49:44 +0530 > Update generic gup implementation with powerpc specific details. > On powerpc at pmd level we can have hugepte, normal pmd pointer > or a pointer to the hugepage directory. > > Signed-off-by: Aneesh Kumar K.V > --- > Changes from V3: > * Drop arm and arm64 changes > * Add hugepte assumption to the function Wait, what are you doing here? You can't assume that a pmd is something you can just go: __pte(pmd_val(x)) with. Not at all. You have to use the correct pmd_*() accessors at all times on this object. Platforms can encode PMDs however they like. In fact, on sparc64, we used to have 32-bit PMDs with a special encoding for huge PMDs that looked nothing at all like a 64-bit PTE. Please code this in a portable manner to support the powerpc facilities, don't add assumptions that are not necessarily universally true. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/