From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 0/2] MMC discard support (was [PATCH 0/7] Discard requests, v2) Date: Fri, 22 Aug 2008 13:19:25 +0200 Message-ID: <20080822111924.GI20055@kernel.dk> References: <1218299181.26926.88.camel@pmac.infradead.org> <20080816190858.4d150ea1@mjolnir.drzeus.cx> <20080822092448.GC20055@kernel.dk> <1219398302.9583.21.camel@pmac.infradead.org> <20080822105039.GG20055@kernel.dk> <1219402696.9583.27.camel@pmac.infradead.org> <20080822131147.5bf0eaaf@mjolnir.drzeus.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Woodhouse , linux-fsdevel@vger.kernel.org To: Pierre Ossman Return-path: Received: from [93.163.65.50] ([93.163.65.50]:24121 "EHLO kernel.dk" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751477AbYHVLT1 (ORCPT ); Fri, 22 Aug 2008 07:19:27 -0400 Content-Disposition: inline In-Reply-To: <20080822131147.5bf0eaaf@mjolnir.drzeus.cx> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Aug 22 2008, Pierre Ossman wrote: > On Fri, 22 Aug 2008 11:58:16 +0100 > David Woodhouse wrote: > > > On Fri, 2008-08-22 at 12:50 +0200, Jens Axboe wrote: > > > > I suspect we need a separate 'max_discard_sectors' field. > > > > > > No, that is what max_hw_sectors is for. > > > > I thought Pierre's problem is that he has _different_ limits for > > discards vs. read/writes? > > > > Indeed. max_hw_sectors is _not_ used for "maximum number of sectors" in > most cases, but for "maximum number of bytes the device can transfer". > The difference between the two is irrelevant for data requests, but is > evident here. OK, I didn't notice the distinction for this case. -- Jens Axboe