Re: [ANNOUNCE] [PATCHES] Advanced TCA Hotswap Support in Linux Kernel

[Greg KH]

On Mon, Oct 14, 2002 at 11:42:15AM -0700, Steven Dake wrote:
> lkml,
> 
> http://www.sourceforge.net/project/showfiles.php?group_id=64580
> 
> I am announcing a sourceforge project for developing support in Linux 
> kernel for Advanced TCA (PICMG 3.0) architecture.  Advanced TCA is a 
> technology where boards exist in a chassis and can either be processor 
> nodes or storage nodes.  All boards in the chassis are connected by 
> FibreChannel and Ethernet.  The blades can be hot added or hot removed 
> while the Linux processor nodes are active, meaning, that the SCSI 
> subsystem must add devices on insertion request and remove devices on 
> ejection requests.  Further the typical /dev/sda naming of devices is 
> not appropriate since device nodes can change depending on the insertion 
> order of disks.
> 
> These patches are for Linux 2.4.19 and work with the Qlogic 2300 
> FibreChannel driver and at this point mostly support hotswap of the disk 
> subsystem.

Some questions:
	- is there a public spec for this architecture?
	- are you going to be generating a 2.5 version of this so that
	  this feature can be added to the main kernel tree?
	- Why don't you use the existing kernel way of notifying
	  userspace of hotplug events, through /sbin/hotplug?
	- You create a lot of new ioctls, which is not nice.  You should
	  probably do what was done for the pci hotplug subsystem, and
	  create a ram based filesystem for this subsystem.  That way
	  you don't need to have a /dev node, and the userspace tools
	  become dirt simple.

thanks,

greg k-h