Re: [RFC as402] Delaying module memory release

[Alan Stern]

On Wed, 27 Oct 2004, Rusty Russell wrote:

> On Tue, 2004-10-26 at 15:52 -0400, Alan Stern wrote:
> > This issue has come up in the past, without much in the way of visible 
> > results.
> > 
> > The problem is that sometimes the memory for a kernel module needs to be
> > freed _after_ rmmod has exited.  The classic example is where the standard
> > input to the rmmod process has been redirected to a pseudo-file that pins
> > a kobject whose release method calls into the module.  Another example
> > (which could be worked around with some effort) is multiple kernel threads
> > executing in the module -- the module exit routine would have to wait for 
> > each one of them to terminate.
> > 
> > In these cases it's not desirable/feasible to increment the module's 
> > refcount.
> 
> Why not?  In the former the module is still in use, in the latter the
> module_exit routine is expected to clean up.

I have to apologize.  Shortly after sending off the earlier email message, 
I realized that the problem with sysfs pinning kobjects had already been 
fixed by taking a reference to the attribute's owner module.  The other 
problem can be handled by other means.  So my proposed change really is 
not needed.

Consider the patch revoked.

Alan Stern

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