Re: MTD kobject warnings due to block layer changes

[Jens Axboe <jens.axboe@oracle.com>]

On Fri, Aug 29 2008, FUJITA Tomonori wrote:
> On Fri, 29 Aug 2008 08:50:30 +0200
> Jens Axboe <jens.axboe@oracle.com> wrote:
> 
> > > Ok, I'll send a patch shortly though it would be better to fix
> > > 'multiple gendisks share a single request_queue'...
> > 
> > Naturally, but we can do that in 2.6.28.
> 
> Yeah, here is a quick fix.
> 
> Manuel, really sorry about the bug and thanks a lot for the
> investigation.
> 
> =
> From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> Subject: [PATCH] remove blk_register_filter and blk_unregister_filter in genhd.c
> 
> This patch remove blk_register_filter and blk_unregister_filter in
> gendisk, and adds them to sd.c and sr.c.
> 
> The commit abf5439370491dd6fbb4fe1a7939680d2a9bc9d4 moved cmdfilter
> from gendisk to request_queue. It turned out that in some subsystems
> multiple gendisks share a single request_queue. So we can't call
> blk_register_filter in add_disk. Otherwise we get:
> 
> Using physmap partition information
> Creating 3 MTD partitions on "physmap-flash":
> 0x00000000-0x01c00000 : "User FS"
> 0x01c00000-0x01c40000 : "booter"
> kobject (8511c410): tried to init an initialized object, something is seriously wrong.
> Call Trace:
> [<8036644c>] dump_stack+0x8/0x34
> [<8021f050>] kobject_init+0x50/0xcc
> [<8021fa18>] kobject_init_and_add+0x24/0x58
> [<8021d20c>] blk_register_filter+0x4c/0x64
> [<8021c194>] add_disk+0x78/0xe0
> [<8027d14c>] add_mtd_blktrans_dev+0x254/0x278
> [<8027c8f0>] blktrans_notify_add+0x40/0x78
> [<80279c00>] add_mtd_device+0xd0/0x150
> [<8027b090>] add_mtd_partitions+0x568/0x5d8
> [<80285458>] physmap_flash_probe+0x2ac/0x334
> [<802644f8>] driver_probe_device+0x12c/0x244
> [<8026465c>] __driver_attach+0x4c/0x84
> [<80263c64>] bus_for_each_dev+0x58/0xac
> [<802633ec>] bus_add_driver+0xc4/0x24c
> [<802648e0>] driver_register+0xcc/0x184
> [<80100460>] _stext+0x60/0x1bc
> 
> In the long term, we need to fix such subsystems but we need a quick
> fix now. This patch add the command filter support to only sd and sr
> though it might be useful for other SG_IO users (like cciss).
> 
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> Reported-by: Manuel Lauss <mano@roarinelk.homelinux.net>
> Cc: Jens Axboe <jens.axboe@oracle.com>
> ---
>  block/cmd-filter.c |    3 ++-
>  block/genhd.c      |    2 --
>  drivers/scsi/sd.c  |    2 ++
>  drivers/scsi/sr.c  |    2 ++
>  4 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/block/cmd-filter.c b/block/cmd-filter.c
> index 1d40262..228b644 100644
> --- a/block/cmd-filter.c
> +++ b/block/cmd-filter.c
> @@ -223,6 +223,7 @@ int blk_register_filter(struct gendisk *disk)
>  
>  	return 0;
>  }
> +EXPORT_SYMBOL(blk_register_filter);
>  
>  void blk_unregister_filter(struct gendisk *disk)
>  {
> @@ -231,4 +232,4 @@ void blk_unregister_filter(struct gendisk *disk)
>  	kobject_put(&filter->kobj);
>  	kobject_put(disk->holder_dir->parent);
>  }
> -
> +EXPORT_SYMBOL(blk_unregister_filter);
> diff --git a/block/genhd.c b/block/genhd.c
> index 656c2c7..d9743ff 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -190,7 +190,6 @@ void add_disk(struct gendisk *disk)
>  			    disk->minors, NULL, exact_match, exact_lock, disk);
>  	register_disk(disk);
>  	blk_register_queue(disk);
> -	blk_register_filter(disk);
>  
>  	bdi = &disk->queue->backing_dev_info;
>  	bdi_register_dev(bdi, MKDEV(disk->major, disk->first_minor));
> @@ -203,7 +202,6 @@ EXPORT_SYMBOL(del_gendisk);	/* in partitions/check.c */
>  
>  void unlink_gendisk(struct gendisk *disk)
>  {
> -	blk_unregister_filter(disk);
>  	sysfs_remove_link(&disk->dev.kobj, "bdi");
>  	bdi_unregister(&disk->queue->backing_dev_info);
>  	blk_unregister_queue(disk);
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index e5e7d78..2a2bc89 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -1875,6 +1875,7 @@ static int sd_probe(struct device *dev)
>  
>  	dev_set_drvdata(dev, sdkp);
>  	add_disk(gd);
> +	blk_register_filter(gd);
>  	sd_dif_config_host(sdkp);
>  
>  	sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
> @@ -1908,6 +1909,7 @@ static int sd_remove(struct device *dev)
>  	struct scsi_disk *sdkp = dev_get_drvdata(dev);
>  
>  	device_del(&sdkp->dev);
> +	blk_unregister_filter(sdkp->disk);
>  	del_gendisk(sdkp->disk);
>  	sd_shutdown(dev);
>  
> diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
> index 27f5bfd..3292965 100644
> --- a/drivers/scsi/sr.c
> +++ b/drivers/scsi/sr.c
> @@ -656,6 +656,7 @@ static int sr_probe(struct device *dev)
>  	dev_set_drvdata(dev, cd);
>  	disk->flags |= GENHD_FL_REMOVABLE;
>  	add_disk(disk);
> +	blk_register_filter(disk);
>  
>  	sdev_printk(KERN_DEBUG, sdev,
>  		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
> @@ -894,6 +895,7 @@ static int sr_remove(struct device *dev)
>  {
>  	struct scsi_cd *cd = dev_get_drvdata(dev);
>  
> +	blk_unregister_filter(cd->disk);
>  	del_gendisk(cd->disk);
>  
>  	mutex_lock(&sr_ref_mutex);

What about eg ide-cd?

-- 
Jens Axboe