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From: Rusty Russell <rusty@rustcorp.com.au>
To: Dave Airlie <airlied@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
	adaplas@pol.net,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dwmw2@redhat.com
Subject: Re: [PATCH] kill symbol_get & friends
Date: Thu, 13 Jan 2005 13:25:47 +1100	[thread overview]
Message-ID: <1105583147.25553.28.camel@localhost.localdomain> (raw)
In-Reply-To: <21d7e997050112165935b89a27@mail.gmail.com>

On Thu, 2005-01-13 at 11:59 +1100, Dave Airlie wrote:
> > For optional module dependencies, weak symbols can be used, but there
> > seems to be a desire for genuine dynamic dependencies.  If you can get
> > rid of those, I'll apply your patch in a second!
> 
> what weak symbol support? can I actually use gcc weak symbols and have
> it all work?
> what happens if the module goes away? 

1) See kernel/module.c:1156 ("/* OK if weak. */").

2) Weak undefined symbols should "just work".  Overriding of weak
defined symbols is not implemented: noone has asked.

3) Like any statically-resolved symbol, this module will hold a
reference to the module exporting the symbol.  The only special thing
about weak symbols is that we don't fail to load if they are unresolved
(and the address will be NULL in this case).

Hope that clarifies,
Rusty.
-- 
A bad analogy is like a leaky screwdriver -- Richard Braakman


  reply	other threads:[~2005-01-13  8:29 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-12 20:31 [PATCH] kill symbol_get & friends Christoph Hellwig
2005-01-13  0:19 ` Rusty Russell
2005-01-13  0:59   ` Dave Airlie
2005-01-13  2:25     ` Rusty Russell [this message]
2005-01-13  8:42     ` David Woodhouse
2005-01-13  4:18   ` Dave Jones
2005-01-13  8:45   ` David Woodhouse
2005-01-13 17:05   ` Christoph Hellwig
2005-01-14  6:56     ` Rusty Russell
2005-01-16 20:46       ` Richard Purdie
2005-01-17  2:47         ` Rusty Russell

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