From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262451AbTEOHUa (ORCPT ); Thu, 15 May 2003 03:20:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262457AbTEOHU3 (ORCPT ); Thu, 15 May 2003 03:20:29 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:5766 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S262451AbTEOHU2 (ORCPT ); Thu, 15 May 2003 03:20:28 -0400 Date: Thu, 15 May 2003 09:29:37 +0200 From: Jens Axboe To: Bharata B Rao Cc: "Martin J. Bligh" , Adrian Bunk , linux-kernel , Suparna Bhattacharya Subject: Re: 2.5.69-mjb1: undefined reference to `blk_queue_empty' Message-ID: <20030515072937.GT15261@suse.de> References: <9380000.1052624649@[10.10.2.4]> <20030512205139.GT1107@fs.tum.de> <20570000.1052797864@[10.10.2.4]> <20030513124807.A31823@in.ibm.com> <25840000.1052834304@[10.10.2.4]> <20030513181155.GL17033@suse.de> <20030514133843.H31823@in.ibm.com> <20030514083224.GC13456@suse.de> <20030515093731.N31823@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030515093731.N31823@in.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 15 2003, Bharata B Rao wrote: > On Wed, May 14, 2003 at 10:32:24AM +0200, Jens Axboe wrote: > > > > That really has to be locked down as well. For your purpose, I think the > > use of elv_queue_empty() is much better even though it really is an > > internal function. The problem mainly comes from AS, that can have non > > empty queue but still return NULL in elv_next_request(). > > > > But yes, it needs to be locked. If you have pinned the other CPUs, then > > I suppose it should work. But it's still a violation of the locking > > rules, and one would get in trouble dropping the queue lock from the io > > scheduler elevator_queue_empty_fn. No one does that currently, but... So > > please take the lock. > > > > Ok, Now we try to acquire the lock and refuse to dump if we don't get > the lock. > > --- 2569+mjb1/drivers/dump/dump_blockdev.c.orig Wed May 14 13:23:36 2003 > +++ 2569+mjb1/drivers/dump/dump_blockdev.c Thu May 15 09:26:12 2003 > @@ -258,10 +258,19 @@ > dump_block_silence(struct dump_dev *dev) > { > struct dump_blockdev *dump_bdev = DUMP_BDEV(dev); > + struct request_queue *q = bdev_get_queue(dump_bdev->bdev); > + int ret; > + > + /* If we can't get request queue lock, refuse to take the dump */ > + if (!spin_trylock(q->queue_lock)) > + return -EBUSY; > + > + ret = elv_queue_empty(q); > + spin_unlock(q->queue_lock); > > /* For now we assume we have the device to ourselves */ > /* Just a quick sanity check */ > - if (!blk_queue_empty(bdev_get_queue(dump_bdev->bdev))) { > + if (!ret) { > /* i/o in flight - safer to quit */ > return -EBUSY; > } Are interrupts already disabled at this point? If yes, then it looks fine. -- Jens Axboe