Messages in this thread | | | Date | Wed, 10 Sep 2008 08:03:18 -0700 | From | "Paul Menage" <> | Subject | Re: [PATCH] cgroups: fix probable race with put_css_set[_taskexit] and find_css_set |
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On Tue, Sep 9, 2008 at 11:29 PM, Greg KH <greg@kroah.com> wrote: > > But you can't put such logic in the release() function as you are > finding out, that's not going to work either.
Right - that's why a kref_put_and_write_lock() function would be handy - it would take the lock only when necessary. It would delegate most of its work to the (as-yet nonexistant) atomic_dec_and_write_lock() function, which would be an rwlock equivalent of atomic_dec_and_lock()
> > Maybe you need to just "open-code" an atomic counter here and not use > kref as it sounds like you are needing to do something very "special" > here. >
It's basically the same situation as the dentry cache - ref-counted objects that are also referenced from a hash table protected by a global lock.
If you're opposed to the addition of kref_put_and_write_lock() then yes, I'll replace kref with a custom refcount.
Paul
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