[PATCH 0/7] Move hardware handlers from dm layer to SCSI layer

[Chandra Seetharaman <sekharan@us.ibm.com>]

Hello,

Set of patches that follow this email facilitate movement of hardware
handlers from dm layer to SCSI layer.

Previous set of patches that implemented this was posted on Jan 24:
http://marc.info/?l=linux-scsi&m=120113462706925&w=2

Changes have been made based on feedback received from James, Alasdair,
Mike Christie and Mike Anderson.

Following are the changes:
 - Removed scsi_dh hardware handler in the dm layer. This means 
   no change (not even a change in the multipath.conf file) is
   required in user space.
 - Replaced REQ_OP_LB_TRANSITION with an activate() function.
 - Removed the SDEV_PASSIVE and added a prep_fn to the device 
   handler, hence giving it the veto power.
 - Replaced blk_execute_rq_nowait() with blk_execute_rq() in
   device handlers to make them synchronous. Added a thread(work queue)
   to dm-multipath to handle requests asynchronously.
 - Added Ed's changes to the EMC hardware handler.
   
Patches are created on top of 2.6.25-rc2-mm1.

Testing has been done with a IBM DS4800 storage device, which means the
infrastructure and the lsi_rdac hardware handler has been tested. Testing
by someone with the EMC hardware and/or HP hardware would be appreciated.

Comments, suggestions solicited.

Thanks,

chandra


-- 

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    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
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