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 Mar 10:
http://marc.info/?l=dm-devel&m=120519925915390&w=2

Changes have been made based on (1)test results from Dave and
(2)discussions with Jens and James:
- Make sure scsi_dh compiles as a modules when scsi is compiled as a
module.
- Set REQ_QUIET flag in the request in rdac hardware handler's prep_fn,
if the path is the passive path (to reduce the extraneous error
messages).

Patches are created on top of 2.6.25-rc5-mm1.

Testing has been done with the following storage devices:
- IBM DS4800 storage device for the lsi_rdac hardware handler
- HP storage device for the hp_sw hardware handler.
Thanks to Dave(dwysocha@redhat.com)
- EMC storage device for the EMC hardware handler.
Thanks to Arthur(Benoit_Arthur@emc.com) and Ronald(asson_ronald@emc.com)
In effect all hardware handlers are tested.

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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Hello,

This is the same set of patches that was posted on Apr 01:
http://marc.info/?l=dm-devel&m=120716401627550&w=2

Only change is that these patches are created on top of 2.6.25-rc8-mm2.

Testing has been done with the following storage devices:
- IBM DS4800 storage device for the lsi_rdac hardware handler
- HP storage device for the hp_sw hardware handler.
Thanks to Dave(dwysocha@redhat.com)
- EMC storage device for the EMC hardware handler.
Thanks to Arthur(Benoit_Arthur@emc.com) and Ronald(asson_ronald@emc.com)
In effect all hardware handlers are tested.

These patches need an ACK from Alasdair(agk@redhat.com).

Thanks,

chandra

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NOTE: This is a resend of the patchset sent on Apr 15 as it did not
reach linux-scsi mailing list

Hello,

This is the same set of patches that was posted on Apr 01:
http://marc.info/?l=dm-devel&m=120716401627550&w=2

Only change is that these patches are created on top of 2.6.25-rc8-mm2.

Testing has been done with the following storage devices:
- IBM DS4800 storage device for the lsi_rdac hardware handler
- HP storage device for the hp_sw hardware handler.
Thanks to Dave(dwysocha@redhat.com)
- EMC storage device for the EMC hardware handler.
Thanks to Arthur(Benoit_Arthur@emc.com) and Ronald(asson_ronald@emc.com)
In effect all hardware handlers are tested.

These patches need an ACK from Alasdair(agk@redhat.com).

Thanks,

chandra

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NOTE: This is a resend (again) of the patchset sent on Apr 15 as it did not
reach linux-scsi mailing list

Hello,

This is the same set of patches that was posted on Apr 01:
http://marc.info/?l=dm-devel&m=120716401627550&w=2

Only change is that these patches are created on top of 2.6.25-rc8-mm2.

Testing has been done with the following storage devices:
- IBM DS4800 storage device for the lsi_rdac hardware handler
- HP storage device for the hp_sw hardware handler.
Thanks to Dave(dwysocha@redhat.com)
- EMC storage device for the EMC hardware handler.
Thanks to Arthur(Benoit_Arthur@emc.com) and Ronald(asson_ronald@emc.com)
In effect all hardware handlers are tested.

These patches need an ACK from Alasdair(agk@redhat.com).

Thanks,

chandra

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Hello,

This is the latest version of the patchset that was posted on Apr 17:
http://marc.info/?l=linux-scsi&m=120847097122545&w=2

Following are the changes made since last post:
Based on Alasdair's comments:
- Split the dm-mpath patch into 4 patches to enhance readabilty
- Added comments to patch header and inline
- Added an interface scsi_dh_handler_exist() and used it
to verify the availability of a hardware handler
- Do not accept arguments with the hardware handler parameter
- Make the workqueue single threaded, and change its name
- removed the usage of path_to_activate and used an existing field
-renamed activate_passive_path to activate_path
- Bring back the pg_init_retries.
Others:
- Added additional devices to the device list
- removed few erroneous BUG assertions
- Fixed an erroneous return code from scsi_dh_rdac.c.

This patch set applies on 2.6.25-mm1.

This patch set has been tested on a DS4800.

Testing has been done earlier with the following storage devices:
- IBM DS4800 storage device for the lsi_rdac hardware handler
- HP storage device for the hp_sw hardware handler.
Thanks to Dave(dwysocha@redhat.com)
- EMC storage device for the EMC hardware handler.
Thanks to Arthur(Benoit_Arthur@emc.com) and Ronald(asson_ronald@emc.com)
In effect all hardware handlers are tested.

-------------------- Comment from Patch 01/10 ---------------------
Some of the storage devices (that can be accessed through multiple paths),
do need some special handling for
1. Activating the passive path of the storage access.
2. Decode and handle the special sense codes returned by the devices.
3. Handle the I/Os being sent to the passive path, especially
during the device probe time.
when accessed through multiple paths.

As of today this special device handling is done at the dm-multipath
layer using dm-handlers. That works well for (1); for (2) to be handled
at dm layer, scsi sense information need to be exported from SCSI to dm-layer,
which is not very attractive; (3) cannot be done at all at the dm layer.

Device handler has been moved to SCSI mainly to handle (2) and (3) properly.
----------------------

Thanks,

chandra

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