From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [dm-devel] [PATCH RFC v1 01/01] dm-lightnvm: An open FTL for open firmware SSDs Date: Mon, 24 Mar 2014 07:13:15 +0100 Message-ID: <532FCCFB.7010007@acm.org> References: <1395383538-18019-1-git-send-email-m@bjorling.me> <1395383538-18019-2-git-send-email-m@bjorling.me> <20140321153749.GA17155@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: snitzer@redhat.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, agk@redhat.com, Takashi HOSHINO To: device-mapper development , Matias Bj??rling Return-path: In-Reply-To: <20140321153749.GA17155@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 03/21/14 16:37, Christoph Hellwig wrote: > Just curious: why do you think implementing this as a block remapper > inside device mapper is a better idea than as a blk-mq driver? > > At the request layer you already get a lot of infrastructure for all the > queueing infrastructure for free, as well as all kinds of other helpers. > And the driver never remaps bios anyway but always submits new ones as > far as I can tell. > > Does it even make sense to expose the underlying devices as block > devices? It surely would help to send this together with a driver > that you plan to use it on top of. There might be some overlap between the functionality available in the lightnvm driver and the WalB driver announced last year. That last driver might have a wider user base and hence may have received more testing. See also http://thread.gmane.org/gmane.linux.file-systems/75124. Bart.