Re: [PATCH 1/3] scsi_dh: Add modalias support for SCSI targets

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Tue, 2009-03-17 at 18:36 -0700, Chandra Seetharaman wrote:
> From: Peter Jones <pjones@redhat.com>
> 
> This patch allows the use of modaliases on scsi targets to correctly
> load scsi device handler modules when the devices are found.
> 
> Signed-off-by: Peter Jones <pjones@redhat.com>
> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>

I have to say this is a bit icky.

overloading the modalias type like this produces several nasty effects:

     1. You don't actually care about type for any of the scsi_dh
        handlers, so they all have it as a useless extra field
     2. TYPE_ANY is a bogus (non SAM) definition ... I suppose it's
        unlikely ever to clash, but you never know
     3. scsi_dh handlers would now get loaded on *any* system ...
        regardless of whether it's using multipathing or not ... that's
        going to cause problems with other multi path solutions, I bet.

Why not use a separately defined module alias for this ... and then
program udev to understand it and do the loading only if multipath is
actually present?  I think we might have to add the INQUIRY strings to
the uenv for this, but it would be a much more elegant solution.

James