Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754743Ab1DFChG (ORCPT ); Tue, 5 Apr 2011 22:37:06 -0400 Received: from ozlabs.org ([203.10.76.45]:33718 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754248Ab1DFChE (ORCPT ); Tue, 5 Apr 2011 22:37:04 -0400 From: Rusty Russell To: Jens Axboe , Takuma Umeya Cc: "virtualization\@lists.linux-foundation.org" , Christoph Hellwig , john cooper , Tejun Heo , "linux-kernel\@vger.kernel.org" Subject: Re: [PATCH] virtio_blk: decrement index when blockdevice is removed In-Reply-To: <4D9AA3BC.6030907@fusionio.com> References: <1969774563.659835.1301978981017.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com> <4D9AA3BC.6030907@fusionio.com> User-Agent: Notmuch/0.3.1 (http://notmuchmail.org) Emacs/23.1.1 (i686-pc-linux-gnu) Date: Wed, 06 Apr 2011 11:02:08 +0930 Message-ID: <87hbacw4fb.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1808 Lines: 45 On Tue, 05 Apr 2011 07:08:12 +0200, Jens Axboe wrote: > On 2011-04-05 06:49, Takuma Umeya wrote: > > When virtio block device is removed, index does not get decremented. When > > another virtio disk is attached it uses the next device letter to the > > one that is suppose to be available. > > > > Signed-off-by: Takuma Umeya > > > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > > index 6ecf89c..730e7af 100644 > > --- a/drivers/block/virtio_blk.c > > +++ b/drivers/block/virtio_blk.c > > @@ -489,6 +489,7 @@ static void __devexit virtblk_remove(struct virtio_device *vdev) > > mempool_destroy(vblk->pool); > > vdev->config->del_vqs(vdev); > > kfree(vblk); > > + index--; > > } > > > > static const struct virtio_device_id id_table[] = { > > What happens when you delete a device that isn't the last one? Obviously we should do something cleverer for assigning drives. It might be a cute if genhd gave us a function to get the next free index for a given major number, and format it for us, like so: /* Return the next available minor for a given @major, at least * @spacing after the previous and, and append appropriate letters * to @name if it's not NULL. -ve errno on fail (-ENOSPC?). */ int disk_next_minor(int major, unsigned spacing, char *name); A trivial optimization would be to remember the last major and max minor (resetting that if any disks are removed). This could clean up other code, too. Cheers, Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/