Messages in this thread | | | Date | Wed, 24 Oct 2007 14:01:06 -0400 (EDT) | From | Alan Stern <> | Subject | Re: BUG in: Driver core: convert block from raw kobjects to core devices |
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On Tue, 23 Oct 2007, Kay Sievers wrote:
> > Yes; I haven't been able to figure out why we get different results. > > > > > There must be something going wrong with the block patch in conjunction > > > with the crazy SCSI release logic.
I found out why it works on my system -- which still leaves open the question of why it fails on yours.
Although the gendisk device is a child of the scsi_device, nevertheless disk->kobj is not a child of the scsi_device's embedded kobject. Instead it is a child of the static (!) block_depr kobject, which is defined in block/genhd.c. Hence the disk's single reference to the scsi_device is indeed dropped when the disk is unregistered, which breaks the loop of circular references.
It works this way because I have CONFIG_SYSFS_DEPRECATED set; perhaps you don't. If you compare the two versions of get_device_parent() in drivers/base/core.c you'll see the difference (it's the dev_type == &disk_type case).
Alan Stern
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