Block Driver Structure Overview

Figure 16–1 shows data structures and routines that define the structure of a block device driver. Device drivers typically include the following elements:

• Device-loadable driver section

• Device configuration section

• Device access section

The shaded device access section in the following figure illustrates entry points for block drivers.

Figure 16–1 Block Driver Roadmap

Associated with each device driver is a dev_ops(9S) structure, which in turn refers to a cb_ops(9S) structure. See Chapter 6, Driver Autoconfiguration for details on driver data structures.

Block device drivers provide these entry points:

• open(9E)

• close(9E)

• strategy(9E)

• print(9E)

Some of the entry points can be replaced by nodev(9F) or nulldev(9F) as appropriate.