Re: [PATCH v4 1/8] SUNRPC: introduce helpers for reference countedrpcbind clients

[Stanislav Kinsbursky]

20.09.2011 18:14, Myklebust, Trond ÐÐÑÐÑ:

> > > Doesn't it  need to be protected by rpcb_clnt_lock too?
> >
> > Nope from my pow. It's protected by rpcb_create_local_mutex. I.e. no one
> > will change rpcb_users since it's zero. If it's non zero - we willn't get to
> > rpcb_set_local().
>
> OK, so you are saying that the rpcb_users++ below could be replaced by rpcb_users=1?

Yes, you right.

> In that case, don't you need a smp_wmb() between the setting of rpcb_local_clnt/4 and the setting of rpcb_users? Otherwise, how do you guarantee that rpcb_users != 0 implies rpbc_local_clnt/4 != NULL?

We check rpcb_users under spinlock. Gain spinlock forces memory barrier, doesn't it?

--
Best regards,
Stanislav Kinsbursky
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