From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 17 Apr 2001 13:05:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 17 Apr 2001 13:05:00 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:9990 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id ; Tue, 17 Apr 2001 13:04:31 -0400 Date: Tue, 17 Apr 2001 19:03:59 +0200 From: Jens Axboe To: "Peter T. Breuer" Cc: linux kernel Subject: Re: block devices don't work without plugging in 2.4.3 Message-ID: <20010417190359.B523@suse.de> In-Reply-To: <200104171640.f3HGeRb32326@oboe.it.uc3m.es> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200104171640.f3HGeRb32326@oboe.it.uc3m.es>; from ptb@it.uc3m.es on Tue, Apr 17, 2001 at 06:40:27PM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 17 2001, Peter T. Breuer wrote: > Well, anyway, as far as I can tell, the following has been lost from > __make_request() in ll_rw_blk.c since the 2.4.0 days: > > out: > - if (!q->plugged) > - (q->request_fn)(q); > if (freereq) > > The result appears to be that if a block device has called > blk_queue_pluggable() to register a no-op plug_fn, then > q->plugged will never be set (it's the duty of the plug_fn), > and the devices registered request function wil never be called. > > This behaviour is distinct from 2.4.0, where registering a > no-op made things work fine. > > Is the policy now supposed to be that we do some more work > in the "no-op"? What am I supposed to do if I don't want > plugging(1)(2)? > > (1) goes away and looks .... > (2) actually, I do want plugging, but I like to keep the > no-plug option around so that I can benchmark the difference > and also provide a very conservative option setting. Not using plugging is dead, blk_queue_pluggable has been killed in the current 2.4.4-pre tree. -- Jens Axboe