scsi_dh update

Hi James, Hannes,

These are the same set of patches that Hannes sent early this morning with the prelog below.

I just ported it to compile clean on top of 2.6.26-git6.

Made 3 additional changes:
1. Added a break under MODE_SELECT option in function get_req() (in 3/8)
2. Added the ifndef portion for scsi_dh_attach() and scsi_dh_detach (in 6/8)
3. Moved the definition of SCSI_DH_DEV_UNSUPP from 6/8 to 3/8.

regards,

chandra
------ Here is the 0/8 from Hannes's original patchset. -----------

Hi James,

this is the (hopefully final) update to my scsi_dh patchset. Features are:

- Move device-table matching into the device_handler infrastructure, so that individual drivers don't have to implement it themselves
- Adds a 'dh_state' sysfs attribute for manually attaching device handler to new or unknown disks; this allows to override the internal device tables
- Update the dm-multipath code to attach the device handler specified in the multipath configuration
- Add a cache to speed up lookup of several identical devices
- Update existing EMC, RDAC, and hp_sw device handler to use the new infrastructure
- Add new SPC-3 ALUA device handler

The NetApp device handler has been left out for now as it's still under development.

Please apply.

Cheers,

Hannes
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