mpr/mps device mapper override

[scottl]

Summary

Create a new sysctl and tunable to help ensure sane numbering of devices.
There are cases where the device_mapper code fails to generating mappings
between device handles and target numbers, or persistent mappings create
unpredictable holes in the numbering. This knob allows the driver to
fall back to a simple phy number mapping if the device mapper fails, or
allows the operator to override the device mapper entirely.

dev.mps.0.use_phy_num
hw.mps.use_phy_num
dev.mpr.0.use_phy_num
hw.mpr.0.use_phy_num

1 - use the PhyNum field as a fallback to the mapping logic
0 - never use the PhyNum field
-1 - only use the PhyNum field

[smh]

Wouldn't it be better to have 0 (the default) be "use the PhyNum field as a fallback to the mapping logic" as that way at least the device would initialise when mpX_mapping_get_sas_id fails?

sys/dev/mpr/mpr.c

1522

typo: enumeration

sys/dev/mpr/mprvar.h

374

use a int8_t?

sys/dev/mps/mps.c

1507

typo

sys/dev/mps/mpsvar.h

387

use a int8_t?

[scottl]

I'll set the default to 1 in the next revision.

sys/dev/mpr/mprvar.h

374

An int is required in order to be type compatible with TUNABLE_INT_FETCH and SYSCTL_ADD_INT. I could work around this with some accessor procedures, but I'm not sure it's worth the extra complication.

[scottl]

Address string typo and move a structure field around to a more logical spot.

[scottl]

Last comment might have been lost. I've set the default to 1.

[smh]

sys/dev/mpr/mprvar.h

374

Ahh not worth the hassle then.