From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755481Ab0F3KZH (ORCPT ); Wed, 30 Jun 2010 06:25:07 -0400 Received: from daytona.panasas.com ([67.152.220.89]:13807 "EHLO daytona.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751947Ab0F3KZF (ORCPT ); Wed, 30 Jun 2010 06:25:05 -0400 Message-ID: <4C2B1B7D.2090607@panasas.com> Date: Wed, 30 Jun 2010 13:25:01 +0300 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Christoph Hellwig CC: James Bottomley , Mike Snitzer , axboe@kernel.dk, dm-devel@redhat.com, linux-kernel@vger.kernel.org, martin.petersen@oracle.com, akpm@linux-foundation.org, linux-scsi@vger.kernel.org, FUJITA Tomonori Subject: Re: [PATCH 1/2] block: fix leaks associated with discard request payload References: <20100622180029.GA15950@redhat.com> <1277582211-10725-1-git-send-email-snitzer@redhat.com> <1277652576.4366.19.camel@mulgrave.site> <4C2B012B.2000407@panasas.com> <20100630084204.GA27609@lst.de> In-Reply-To: <20100630084204.GA27609@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 30 Jun 2010 10:25:04.0894 (UTC) FILETIME=[8171A9E0:01CB183E] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/30/2010 11:42 AM, Christoph Hellwig wrote: > On Wed, Jun 30, 2010 at 11:32:43AM +0300, Boaz Harrosh wrote: >> May I ask a silly question? Why the dynamic allocation? >> >> Why not have a const-static single global page at the block-layer somewhere >> that will be used for all discard-type operations and be done with it once and >> for all. A single page can be used for any size bio , any number of concurrent >> discards, any ZERO needed operation. It can also be used by other operations >> like padding and others. In fact isn't there one for the libsata padding? > > for UNMAP we need to write into the payload. And for ATA TRIM we need > to write into the WRITE SAME payload. OK, Thanks, I see. Is it one of these operations, (like we have in OSD) where the CDB information spills into the payload? like the scatter-gather and extent lists and such. Do we actually use a WRITE_SAME which is not zero? for what use? > That's another layering violation > for those looking for them, btw.. > Agreed