Re: [RFC][PATCH] identify in_dev_get rcu read-side critical sections

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Wed, Sep 28, 2005 at 07:51:10AM -0700, Paul E. McKenney wrote:
> 
> The reference-count approach is only guaranteed to work if the kernel
> thread that did the reference-count increment is later referencing that
> same data element.  Otherwise, one has the following possible situation
> on DEC Alpha:

You're quite right.  Without the rcu_dereference users of in_dev_get()
may see pre-initialisation contents of in_dev.

So these barriers are definitely needed.

Thanks,
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