Need of MODULE_LICENSE("GPL")

[Ivan Nikolaev]

On Thu 20 Dec 2012 11:34:13 AM CET, Niroj Pokhrel wrote:
>
>
> On Thu, Dec 20, 2012 at 4:00 PM, Ivan Nikolaev <voidexp at gmail.com
> <mailto:voidexp at gmail.com>> wrote:
>
>     Modules which are not declared.as <http://declared.as> GPL, by
>     default are considered proprietary. Proprietary code can't make
>     use of GPLed modules.
>
>     20.12.2012 12:03 пользователь "Niroj Pokhrel"
>     <nirojpokhrel at gmail.com <mailto:nirojpokhrel at gmail.com>> написал:
>
>         Hi,
>         While writing a device driver, I noticed
>         MODULE_LICENSE("GPL"). When I omitted it, I got several error
>         like device_create, device_destroy, class_create,
>         class_destroy is not recognized symbol. I am just wondering
>         what is the use of this macro and how does it helps in
>         defining the symbols. Thanks in advance.
>
>         --
>         Niroj Pokhrel
>         Software Engineer,
>         Samsung India Software Operations
>
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>
>
> Thank you Ivan. But can you please give me some insight on proprietary
> code and GPLed modules. Thanking you in advance.
>
> --
> Niroj Pokhrel
> Software Engineer,
> Samsung India Software Operations

Well, basically, all drivers and code shipped with kernel are GPL'ed. 
Kernel's API can be called from any kind of module, proprietary or open 
source. This does not extend for modules. If I write a module and 
release it under GPL, everyone else who wants to use that module must 
also release it under GPL.