Managing and Developing Dynamically Loadable Kernel Modules

Developing Dynamically Loadable Kernel Modules

Chapter 12 541

NOTE The wsio_install_driver() function call returns 1 on success.

However (and inconsistently), the wsio_uninstall_driver()

function call returns 0 on success.

Initialization for a statically linked WSIO class driver is unchanged from

historical practice. That is, the initial driver entry point is

module_name

_install. This function typically installs an _init()

function in a list of functions that will be invoked later in the system boot

process, and then the driver registers itself with WSIO. For example:

Example 12-4 WSIO Class Driver _install Function

static void

module_name

_linked_init (void);

static int (*

module_name

_saved_init)();

* INSTALL

* This function is called if module is statically linked.

int

module_name

_install(void)

{

extern int (*dev_init)(void);

/* Link my init function into chain */

module_name

_saved_init = dev_init;

dev_init = (int (*)()) &

module_name

_linked_init;

/* Register driver with WSIO */

return ( wsio_install_driver(&

module_name

_wsio_info) );

}

The _init() function in the static case must call the next driver's

_init() function: