From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH] scatterlist: enable sg chaining for all architectures Date: Tue, 28 Apr 2015 14:27:43 -0700 Message-ID: <20150428142743.578d1c930aca013b596d7546@linux-foundation.org> References: <1429973776-7499-1-git-send-email-akinobu.mita@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1429973776-7499-1-git-send-email-akinobu.mita@gmail.com> Sender: linux-arch-owner@vger.kernel.org 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 List-Id: linux-scsi@vger.kernel.org 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!