Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966225AbbD1V1r (ORCPT ); Tue, 28 Apr 2015 17:27:47 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33567 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966024AbbD1V1p (ORCPT ); Tue, 28 Apr 2015 17:27:45 -0400 Date: Tue, 28 Apr 2015 14:27:43 -0700 From: Andrew Morton To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, Arnd Bergmann , linux-arch@vger.kernel.org, "James E.J. Bottomley" , Christoph Hellwig , linux-scsi@vger.kernel.org, "Nicholas A. Bellinger" , target-devel@vger.kernel.org Subject: Re: [PATCH] scatterlist: enable sg chaining for all architectures Message-Id: <20150428142743.578d1c930aca013b596d7546@linux-foundation.org> In-Reply-To: <1429973776-7499-1-git-send-email-akinobu.mita@gmail.com> References: <1429973776-7499-1-git-send-email-akinobu.mita@gmail.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-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 Content-Length: 1074 Lines: 23 On Sat, 25 Apr 2015 23:56:16 +0900 Akinobu Mita wrote: > Some architectures enable sg chaining option while others do not. > > The requirement to enable sg chaining is that pages must be aligned > at a 32-bit boundary in order to overload the LSB of the pointer. > Regardless of whether ARCH_HAS_SG_CHAIN is defined or not, the above > requirement is always chacked by BUG_ON() in sg_assign_page. So > all architectures can enable sg chaining. > > As you can see from the changes in drivers/target/target_core_rd.c, > enabling SG chaining for all architectures allows us to allocate > discontiguous scatterlist tables which can be traversed throughout > by sg_next() without a special handling for some architectures. Thanks, I'll grab this. If anyone has concerns, speak now or hold both pieces! -- 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/