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

Chandra Seetharaman sekharan at us.ibm.com
Thu Feb 28 01:08:28 UTC 2008


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 at us.ibm.com   |      .......you may get it.
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