Re: [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2]

David Howells
2010-03-31T17:37:40Z

Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> Protected by something that the caller did, be it holding the the correct
> lock, operating on it during initialization before other CPUs have access
> to it, operating on it during cleanup after other CPUs' access has been
> revoked, or whatever.

But the point I made very early this morning still stands: What if someone
simply wants to test the pointer, not actually to dereference it?

NFS was using rcu_dereference() for this in a couple of places - which is
overkill. I suggested stripping this off and you countered with the
suggestion that it should be using rcu_dereference_check().

Why do I need anything at all?

David