From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: [RFC] Remove of ISA pools, and Lazy sense allocation. Date: Mon, 12 May 2008 16:03:01 +0300 Message-ID: <48284005.8010407@panasas.com> References: <48218B24.4000507@panasas.com> <20080508004308U.tomof@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from gw-colo-pa.panasas.com ([66.238.117.130]:10410 "EHLO cassoulet.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755654AbYELNDs (ORCPT ); Mon, 12 May 2008 09:03:48 -0400 In-Reply-To: <20080508004308U.tomof@acm.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: andi@firstfloor.org, James.Bottomley@hansenpartnership.com, linux-scsi@vger.kernel.org, bhalevy@panasas.com FUJITA Tomonori wrote: > On Wed, 07 May 2008 13:57:40 +0300 > Boaz Harrosh wrote: > >> Let me please explain a bit on my sense_buffer patchset and where I was going >> with these: >> >> Currently every ULD/Initiator that pushes request to block devices puts a sense >> buffer of SCSI_SENSE_BUFFERSIZE size onto request->sense pointer. scsi-midlayer >> shadows that buffer, for what it thought as a DMAable buffer for drivers, and at >> completion of request copies the shadow buffer back into ULD's buffer. >> >> I have observed three uses of sense_buffer handling in scsi drivers: > > I just had a quick look at only some of patches, but where do you > allocate rq->sense for fs requests? > > > Here are some comments: > > scsi_eh: Define API for driver private sense allocation > > +struct scsi_sense_elem { > + union { > + struct scsi_sense_elem *next; > + u8 sense_data[SCSI_SENSE_BUFFERSIZE] ____cacheline_aligned; > + }; > +} ____cacheline_aligned; > > > I think that this is wrong since all the architecutures don't have > such dma restriction. ARCH_KMALLOC_MINALIGN? > > There is the same code in The libata patch at least. I guess there are > more. Tomo you are absolutely right there is no sense allocated for fs commands. Which makes all this useless. I will go dig a big hole under a rock and stay there for a year in shame. Please forgive me all for the noise. Boaz