Linux Device Drivers

Quick Reference

This chapter introduced the following kernel symbols:

/etc/modules.conf

The configuration file for modprobe and depmod. It is used to configure demand loading and is described in the man pages for the two programs.

#include <linux/kerneld.h> , int request_module(const char *name); , int release_module(const char *name, int waitflag); , int delayed_release_module(const char *name); , int cancel_release_module(const char *name);

These functions perform demand loading of modules by means of the kerneld daemon.

#include <linux/autoconf.h> , CONFIG_MODVERSIONS

This macro is defined only if the current kernel has been compiled to support versioned symbols.

#ifdef MODVERSIONS , #include <linux/modversions.h>

This header, which exists only if CONFIG_MODVERSIONS is valid, contains the versioned names for all the symbols exported by the kernel.

EXPORT_SYMTAB

If version support is used, this macro must be defined if your module uses register_symtab to export symbols of its own.

__GENKSYMS__

This macro is defined by make when preprocessing files to be read by genksyms to build new version codes. It is used to conditionally prevent inclusion of <linux/modversions.h> when building new checksums.

int set_persist(char *key, void *value, size_t length); , int get_persist(char *key, void *value, size_t length);

Support for persistent storage of module data relies on these two functions, which are defined in <linux/kerneld.h>.