RE: How to add/drop SCSI drives from within the driver?

From: Bagalkote, Sreenivas
Date: Wed Dec 08 2004 - 13:14:10 EST

>On Wed, 2004-12-08 at 01:16, Bagalkote, Sreenivas wrote:
>> Adding a drive:- For application to use sysfs to scan newly added
>> drive, it needs to know the HCTL (SCSI address - Host,
>Channel, Target
>> & Lun) of the drive. Driver is the only one that knows the mapping
>> between a drive and the corresponding HCTL.
>The real way I'd like to handle this is via hotplug. The
>hotplug event would transmit the HCTL in the environment.
>Whether the drive actually gets incorporated into the system
>and where is user policy, so it's appropriate that it should
>be in userland.

James, it is the application that is adding the drive. So it is not a
event for the driver.

>This same infrastructure could be used by fibre channel login,
>scsi enclosure events etc.
>We have some of the hotplug infrastructure in SCSI, but not
>quite enough for this ... you'll need an additional API.
>> Removing a drive:- There is no sane way for the application
>to map out
>> drives to /dev/sd<x>. If application has a way of knowing
>the HCTL of
>> a deleted drive, then using that HCTL, it can match the
>> SCSI device name (/dev/sd<x>) and use sysfs to remove that drive.
>Since The sysfs device name contains H:C:T:L surely you can
>just do a find on /sys?

Thank you,
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