From mboxrd@z Thu Jan 1 00:00:00 1970 From: FUJITA Tomonori Subject: Re: [PATCH 1/4] block: use ARCH_KMALLOC_MINALIGN as the default dma pad mask Date: Wed, 21 May 2008 18:34:45 +0900 Message-ID: <20080521183429O.tomof@acm.org> References: <20080521031646.GA16565@gondor.apana.org.au> <20080521155414D.fujita.tomonori@lab.ntt.co.jp> <20080521084700.GA18644@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from mo11.iij4u.or.jp ([210.138.174.79]:58804 "EHLO mo11.iij4u.or.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750963AbYEUJgT (ORCPT ); Wed, 21 May 2008 05:36:19 -0400 In-Reply-To: <20080521084700.GA18644@gondor.apana.org.au> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: herbert@gondor.apana.org.au Cc: fujita.tomonori@lab.ntt.co.jp, akpm@linux-foundation.org, linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, jens.axboe@oracle.com, tsbogend@alpha.franken.de, bzolnier@gmail.com, James.Bottomley@HansenPartnership.com, jeff@garzik.org, davem@davemloft.net, linux-mm@kvack.org On Wed, 21 May 2008 16:47:00 +0800 Herbert Xu wrote: > On Wed, May 21, 2008 at 03:54:14PM +0900, FUJITA Tomonori wrote: > > > > As explained, with the current way we define ARCH_KMALLOC_MINALIGN, > > crypto doesn't need to use it. But to make it clear, we had better > > clean up these defines, such as renaming it an appropriate name like > > ARCH_DMA_ALIGN. > > No you don't understand the way crypto is using it. We need to > know exactly the minimum alignment guaranteed by kmalloc. Too much > or too little are both buggy. Why do crypto need to know exactly the minimum alignment guaranteed by kmalloc? Can you tell me an example how the alignment breaks crypto? For me, the way crypto use it is idential to what the hostdata in struct Scsi_Host does.