FreeBSD kernel 笔记(9)——modeventtype_t定义

modeventtype_t定义如下:

typedef enum modeventtype {
    MOD_LOAD,
    MOD_UNLOAD,
    MOD_SHUTDOWN,
    MOD_QUIESCE
} modeventtype_t;
typedef int (*modeventhand_t)(module_t, int /* modeventtype_t */, void *);

MOD_LOADMOD_UNLOADMOD_SHUTDOWN都好理解。分别是在加载,卸载模块,还有关机时传入模块处理函数的值。而关于MOD_QUIESCE可以参考FreeBSD Device Drivers

When one issues the kldunload(8) command, MOD_QUIESCE is run before MOD_UNLOAD . If MOD_QUIESCE returns an error, MOD_UNLOAD does not get executed. In other words, MOD_QUIESCE verifies that it is safe to unload your module.

NOTE The kldunload -f command ignores every error returned by MOD_QUIESCE . So you can always unload a module, but it may not be the best idea.

另外,关于MOD_QUIESCEMOD_SHUTDOWN区别,也可参考FreeBSD Kernel Developer’s Manual

The difference between MOD_QUIESCE and MOD_UNLOAD is that the module should fail MOD_QUIESCE if it is currently in use, whereas MOD_UNLOAD should only fail if it is impossible to unload the module, for instance because there are memory references to the module which cannot be revoked.

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