Re: [1/1] Export __lock_page_killable()

Evgeniy Polyakov
2008-05-14T14:32:44Z

Hi Alan.

On Wed, May 14, 2008 at 03:13:56PM +0100, Alan Cox (alan@lxorguk.ukuu.org.uk) wrote:
> > There are users, who would like to use lock_page_killable() in modules,
> > so far there are no users in kernel, but for consistency it can be
> > exported without them.
>
> Missing information #1: Who are the users and what are the URLs to the
> code in question

POHMELFS wants to use that in two places: one to lock page in writeback,
another one is about second part of the message - it waits for timeout
or signal or locks the page. If page can not be locked, it performs own
steps, not sleeps forever...

POHMELFS is a high performance network filesystem, homepage for interested
reader:
http://tservice.net.ru/~s0mbre/old/?section=projects&item=pohmelfs
or yesterdays mail to mail lists:
http://lwn.net/Articles/282010/

> > Not that it is particulary needed
>
> Humm..

I copied page_waitqueue() and use wait_on_bit() logic myself.
Andrew choked with his breakfast when saw that.

> > +EXPORT_SYMBOL(__lock_page_killable);
>
> _GPL - or better yet this could be added *when* we have an actual in tree
> user who really needs it and can show it is appropriate to export.
> That'll also save Adrian from removing it again ;)

No problem wiht GPL-only exporting, but carring it over the whole
release means no ability to build out-of-tree module.

Actually what I want to hear, is that it is needed or not at all...

--
Evgeniy Polyakov