From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH V2 0/4] Add MMC erase and secure erase Date: Mon, 14 Jun 2010 14:10:06 +0300 Message-ID: <4C160E0E.4010802@nokia.com> References: <4C14AC7E.6030308@nokia.com> <20100614080921.GA28316@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.nokia.com ([192.100.122.233]:34600 "EHLO mgw-mx06.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756044Ab0FNLKh (ORCPT ); Mon, 14 Jun 2010 07:10:37 -0400 In-Reply-To: <20100614080921.GA28316@lst.de> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Christoph Hellwig Cc: "jens.axboe@oracle.com" , Andrew Morton , Kyungmin Park , LKML , "linux-mmc@vger.kernel.org" , Madhusudhan Chikkature Christoph Hellwig wrote: > On Sun, Jun 13, 2010 at 01:01:34PM +0300, Adrian Hunter wrote: >> Hi >> >> Add ability to do MMC erase and secure erase operations from userspace, >> using the BLKDISCARD ioctl and a newly created BLKSECDISCARD ioctl. > > Have you done any measurement if the use of the block layer changes > performance of the discard requests for you? No. For my purposes there will be only 1 discard request for the entire device which will take several minutes to process, so block layer performance is not a factor. > I'd really prefer to > send down the secure erase that way, too. This could easily be done > by having a DISCARD_SECURE rw flag, which just ORs another flag into > the request type field. Needs a bio flag, a request flag, setup the request flag based on the bio flag, prevent merging secure and non-secure discards, prevent drivers doing non-secure discards for secure discards. Seems like a lot of little changes for something that no one wants. Shouldn't it wait for someone to need it first?