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><TT
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>__initcall()</TT
>/<TT
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<TT
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> Many parts of the kernel are well served as a module
(dynamically-loadable parts of the kernel). Using the
<TT
CLASS="FUNCTION"
>module_init()</TT
> and
<TT
CLASS="FUNCTION"
>module_exit()</TT
> macros it is easy to write code
without #ifdefs which can operate both as a module or built into
the kernel.
</P
><P
> The <TT
CLASS="FUNCTION"
>module_init()</TT
> macro defines which
function is to be called at module insertion time (if the file is
compiled as a module), or at boot time: if the file is not
compiled as a module the <TT
CLASS="FUNCTION"
>module_init()</TT
> macro
becomes equivalent to <TT
CLASS="FUNCTION"
>__initcall()</TT
>, which
through linker magic ensures that the function is called on boot.
</P
><P
> The function can return a negative error number to cause
module loading to fail (unfortunately, this has no effect if
the module is compiled into the kernel). For modules, this is
called in user context, with interrupts enabled, and the
kernel lock held, so it can sleep.
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