Re: [PATCH 60/80] tty: extract the pty init time special cases

From: Alan Cox
Date: Wed Jan 28 2009 - 15:59:08 EST


> So you are saying that if I merge my ptyx module into the kernel tree THEN
> these
> exports would be added? They would have to be, since I would still want

It would then seem reasonable to do so

> my
> driver to be a module instead of statically linked with the kernel like
> pty is.

Sure - although it might make more sense to add any neede features to the
generic pty driver - hard to tell when you don't seem interested in
discussing that.

> I think the fact that you had to "ask at the time what other PTY drivers
> there
> were" indicates that these symbols should have been simply exported to
> avoid
> any problems with out of tree PTY drivers.

The linux kernel doesn't carry extra symbols for out of tree drivers. Why
should it - even keeping an index of them would be hard and it would be
impossible to know which ones are in use. Plus they change regularly -
the tty layer will change further soon for example, it's just having a
settling in period before the next big changes.

> By not exporting these symbols it means that the Linux kernel is now
> forcing
> anyone who wants to develop a PTY type TTY driver to be merged into the
> kernel
> tree by not exporting these TTY functions. This doesn't seem very "open
> and
> flexible".

No you can provide the GPL symbol exports with the same patch as your pty
driver. There are millions of Linux users and each unused EXPORT_SYMBOL
costs memory to all those people - why should they carry that burden ?

Alan
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