Synchronization primitives

DDI includes several sets of functions and structures that are used to control synchronization between the hardware and the driver and to protect critical code. These primitives that are available include:

• ``Atomic locks''

• ``Sleep locks''

• ``Spin locks (DDI)''

• ``Spin locks (ODDI)''

• ``Synchronization variables''

• ``Trylocks''

• ``Timeouts''

• ``Delays and busy-waits''

• biowait(D3) and biodone(D3) for block I/O operations that use the buf(D4) structure.

• sleep(D3) and wakeup(D3) for hardware synchronization in non-multithreaded drivers written to conform to DDI version 6 and earlier.

• spl(D3) to protect critical code regions in non-multithreaded drivers.

Drivers must use the appropriate synchronization primitive for the functionality required, the context in which the operation runs, and the DDI version being used.