scsi_dh: Move dm device handler to SCSI layer
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- v1 Latest9 patches 27 repliesIn review
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/9 | scsi_dh: add REQ_LB_OP_TRANSITION and errorsblock/ include/ | +42 | 0 replies | |
| 2/9 | scsi_dh: change sd_prep_fn to call common codedrivers/ drivers/ include/ | +4 | 0 replies | |
| 3/9 | scsi_dh: scsi handling of REQ_LB_OP_TRANSITIONdrivers/ include/ include/ | +125 | 5 replies | |
| 4/9 | scsi_dh: add skeleton for SCSI Device Handlersdrivers/ drivers/ drivers/ +4 more | +77 | 3 replies | |
| 5/9 | scsi_dh: add EMC Clariion device handlerdrivers/ drivers/ drivers/ | +368 | 0 replies | |
| 6/9 | scsi_dh: add hp sw device handlerdrivers/ drivers/ drivers/ | +213 | 0 replies | |
| 7/9 | scsi_dh: Add support for SDEV_PASSIVEdrivers/ include/ | +15 | 19 replies | |
| 8/9 | scsi_dh: add lsi rdac device handlerdrivers/ drivers/ drivers/ | +772 | 0 replies | |
| 9/9 | scsi_dh: add scsi device handler to dmdrivers/ drivers/ drivers/ | +193 | 0 replies |
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Cover letter [PATCH 0/9] scsi_dh: Move dm device handler to SCSI layer
Hello,
The set of patches that follow this email facilitate movement of hardware handlers from dm layer to SCSI layer.
Patches posted along with this email are based off of the patches Mike Christie posted on June 09, 2007. The first email Mike posted gives the rationale for moving the hardware handler from dm to SCSI.
Patches posted by Mike Christie:
http://marc.info/?l=linux-scsi&m=118141609715090&w=2
http://marc.info/?l=linux-scsi&m=118141614418681&w=2
http://marc.info/?l=linux-scsi&m=118141614501241&w=2
http://marc.info/?l=linux-scsi&m=118141614303990&w=2
http://marc.info/?l=linux-scsi&m=118141614425996&w=2
http://marc.info/?l=linux-scsi&m=118141802719861&w=2
http://marc.info/?l=linux-scsi&m=118141614331436&w=2
http://marc.info/?l=linux-scsi&m=118141614421759&w=2
Current set of patches has 3 additional advantages:
1. It is totally compatible with the current multipath tools.
2. Moving from dm hardware handler to SCSI hardware handler is not imposed on the user community. They can use either of those by using either of the modules.
dm hardware handler can be depracated slowly.
3. It adds a new device state SDEV_PASSIVE which avoids I/O being sent to the passive side of a multipath device, thereby reducing the device probe time and boot time.
Booting a system with 40 luns with 1 active path and 1 inactive path shows the following as the last printk before login prompt.
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With SCSI HW Handler
[ 171.702366] Buffer I/O error on device sdbl, logical block 262128
Without SCSI HW Handler
[ 1426.772390] end_request: I/O error, dev sdbm, sector 2097136
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Patches are created on top of 2.6.24-rc8-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
Signature · 4 lines
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Chandra Seetharaman | Be careful what you choose....
- [email protected] | .......you may get it.
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