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Subject: Re: How to add/drop SCSI drives from within the driver?
From: James Bottomley <James.Bottomley@SteelEye.com>
To: Matt Domsch <Matt_Domsch@Dell.com>
Cc: "Salyzyn, Mark" <mark_salyzyn@adaptec.com>,
       "Bagalkote, Sreenivas" <sreenib@lsil.com>, brking@us.ibm.com,
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       "Doelfel, Hardy" <hdoelfel@lsil.com>, "Mukker, Atul" <Atulm@lsil.com>
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Organization: SteelEye Technology, inc.
Date: Wed, 15 Dec 2004 13:49:18 -0500
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On Wed, 2004-12-15 at 01:24 -0600, Matt Domsch wrote:
> James, I've been thinking about this a little more, and you may be on
> to something here. Let each driver add files as such:
> 
> /sys/class/scsi_host
>  |-- host0
>  |   |-- add_logical_drive
>  |   |-- remove_logical_drive
>  |   `-- rescan_logical_drive
> 
> Then we can go 2 ways with this.
> 1) driver functions directly call scsi_add_device(),
> scsi_remove_device(), and something for rescan (option 2 handles this
> one cleanly for us).  ATM, megaraid_mbox doesn't implement a rescan
> function, so this point may be moot. 
> 
> 2) driver functions call a midlayer library function, which invokes
>    /sbin/hotplug with appropriate data, and add a new /etc/hotplug.d
>    helper app which would then write to these files:
> 
> /sys/class/scsi_host
> |-- host0
> |   |-- scan
> /sys/devices/pci0000:0x/0000:0x:0x.0/host0
> |-- 0:0:0:0
> |   |-- delete
> |   |-- rescan
> 
> to do likewise.

I'll buy this (option 2).. it seems like a good way to export the
megaraid specific information and at the same time integrate it more
fully into the evolving hotplug infrastructure.

James