Re: [RFC] scsi host sysfs support again [0/4]

[Mike Anderson <andmike@us.ibm.com>]

Douglas Gilbert [dougg@torque.net] wrote:
> [HBA REMOVAL new]
> LLD                      mid level                 LLD
> ---                      ---------                 ---
> scsi_remove_host() ---------+
>                             |
>                      slave_destroy()
>                      slave_destroy()
>                         release()     -->     scsi_unregister()
> 
> In the new model there is nothing left to do after
> scsi_remove_host() has finished since everything happened
> during that call. The the LLD is re-entered to cleanup
> up any HBA specific device resources (slave_destroy()).
> Finally the LLD is re-entered by the release().
> 
> Also module unloads (should) use the ->remove
> method as well. Does the LLD need to know
> whether a HBA removal is hot or not?
> 

I believe Christoph is indicating that if something has a ref on
scsi_host and this causes the release to be called after the return from
scsi_remove_host than this would not be good. I believe the LLDD model
would stay like the old method except in the mid layer there would be a
change in how / when kfree(shost) is called.

LLD			mid level
scsi_remove_host()  -----+
                         |
		     slave_destroy()
		     slave_destroy()
		     slave_destroy()
scsi_unregister()  ------+
			 |
			 kfree of scsi_host may happen here or sometime
			 later depending on the ref count.


-andmike
--
Michael Anderson
andmike@us.ibm.com