Re: [patch] Add kref_read and kref_put_last primitives

[Dipankar Sarma <dipankar@in.ibm.com>]

On Mon, Aug 02, 2004 at 01:08:49PM -0700, Greg KH wrote:
> On Mon, Jul 26, 2004 at 05:31:51PM +0100, Christoph Hellwig wrote:
> > Why don't you simply use an atomic_t if that's what you seem to
> > want?
> 
> Exactly.  In cases like this, where the user, for some reason, wants to
> know the state of the reference count, they should not use a struct
> kref.  I'm not going to add these functions to the kref api, sorry.
> 

Really, there is no need to use kref in where Ravikiran is using
them (VFS) under the current circumstances. However, if lock-free 
lookup using RCU is to be used, Ravikiran needs to use an abstracted reference 
counter API. This is to optimally support platforms with and without 
cmpxchg. kref is the standard reference counter API at the moment and 
that is where it made sense to add the abstracted lockfree reference counter
support.

So, kref_read() as it is would look weird. But if we consider merging
the rest of the kref APIs (lock-free extensions) in future, then the
entire set including kref_read() would make sense.

Thanks
Dipankar