Re: [PATCH 5/5] sunrpc/auth_gss: Call rcu_barrier() on module unload.

Jesper Dangaard Brouer
2009-06-08T19:49:41Z

(trimmed Cc)

On Mon, 8 Jun 2009, Trond Myklebust wrote:

> Hmm... If this is about ensuring that all the call_rcu() callbacks
> complete before we remove the module, then don't we also need similar
> barriers in

Well, Trond that was a hard question, as I don't know this code... but if
it uses call_rcu() callbacks its most likely.

I have not done a complete sweep of the tree, I have only looked at the
netdev parts, as this is where I usually snoop around. So there is
probably plenty of work for some kernel-janitors (Cc'ing the list ;-))

> net/sunrpc/sunrpc_syms.c:cleanup_sunrpc()

Looking at the code that end up in sunrpc.ko, I see that both
net/sunrpc/auth_unix.c and net/sunrpc/auth_generic.c uses call_rcu()
callbacks.

> and in fs/nfs/inode.c:exit_nfs_fs()?

Looking at the code which end up into nfs.ko (which includes
fs/nfs/inode.c) I see that the fs/nfs/delegation.c uses call_rcu()
callbacks.

But its hard for me to figure out how this code interacts. Don't know if
we need to document a code path that can occur fast enough, before we add
this safe guard? It should be Paul's saying...

Cheers,
Jesper Brouer

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