Notes and examples for multithreaded block drivers

To illustrate how block drivers are multithreaded, the following sections contain annotated code fragments. Two main areas are covered:

• The driver must register itself as multithreaded during its initialization routine.

• Block I/O operations are coded in the driver's strategy(D2oddi) and start(D2oddi) routines. For multithreaded drivers, a series of lock_xxtab structures are used with the lockb(D3oddi) and unlockb(D3oddi) functions to maintain data integrity. The following sections illustrate how the strategy( ), start( ), and intr( ) routines are coded for multithreaded drivers.