Pass unit number to bcache_strategy(), so that the cache can be flushed if the unit changes. Compute the absolute offset before bcache_strategy() instead of after.
Pass unit number to bcache_strategy(), so that the cache can be
flushed if the unit changes. Compute the absolute offset before
bcache_strategy() instead of after.

The actual fix is sligthly different for the one in the PR.

PR:		17098
Submitted by:	John Hood <jhood@sitaranetworks.com>

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase