Re: [PATCH] New operation for kref to help avoid locks

From: Greg KH
Date: Tue Mar 01 2005 - 15:58:26 EST


On Sat, Feb 26, 2005 at 04:23:04PM -0600, Corey Minyard wrote:
> Add a routine to kref that allows the kref_put() routine to be
> unserialized even when the get routine attempts to kref_get()
> an object without first holding a valid reference to it. This is
> useful in situations where this happens multiple times without
> freeing the object, as it will avoid having to do a lock/semaphore
> except on the final kref_put().
>
> This also adds some kref documentation to the Documentation
> directory.

I like the first part of the documentation, that's nice.

But I don't like the new kref_get_with_check() function that you
implemented. If you look in the -mm tree, kref_put() now returns if
this was the last put on the reference count or not, to help with lists
of objects with a kref in it.

Perhaps you can use that to implement what you need instead?

thanks,

greg k-h
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