| Re: [PATCH v6 1/8] SUNRPC: introduce helpers for reference counted rpcbind clients [message #43859 is a reply to message #43852] |
Tue, 25 October 2011 11:16   |
Trond Myklebust
Messages: 24
Registered: July 2006
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Junior Member |
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On Tue, 2011-10-25 at 14:16 +0300, Stanislav Kinsbursky wrote:
> v6:
> 1) added write memory barrier to rpcb_set_local to make sure, that rpcbind
> clients become valid before rpcb_users assignment
> 2) explicitly set rpcb_users to 1 instead of incrementing it (looks clearer from
> my pow).
>
> v5: fixed races with rpcb_users in rpcb_get_local()
>
> This helpers will be used for dynamical creation and destruction of rpcbind
> clients.
> Variable rpcb_users is actually a counter of lauched RPC services. If rpcbind
> clients has been created already, then we just increase rpcb_users.
>
> Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
>
> ---
> net/sunrpc/rpcb_clnt.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 54 insertions(+), 0 deletions(-)
>
> diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
> index e45d2fb..9fcdb42 100644
> --- a/net/sunrpc/rpcb_clnt.c
> +++ b/net/sunrpc/rpcb_clnt.c
> @@ -114,6 +114,9 @@ static struct rpc_program rpcb_program;
> static struct rpc_clnt * rpcb_local_clnt;
> static struct rpc_clnt * rpcb_local_clnt4;
>
> +DEFINE_SPINLOCK(rpcb_clnt_lock);
> +unsigned int rpcb_users;
> +
> struct rpcbind_args {
> struct rpc_xprt * r_xprt;
>
> @@ -161,6 +164,57 @@ static void rpcb_map_release(void *data)
> kfree(map);
> }
>
> +static int rpcb_get_local(void)
> +{
> + int cnt;
> +
> + spin_lock(&rpcb_clnt_lock);
> + if (rpcb_users)
> + rpcb_users++;
> + cnt = rpcb_users;
> + spin_unlock(&rpcb_clnt_lock);
> +
> + return cnt;
> +}
> +
> +void rpcb_put_local(void)
> +{
> + struct rpc_clnt *clnt = rpcb_local_clnt;
> + struct rpc_clnt *clnt4 = rpcb_local_clnt4;
> + int shutdown;
> +
> + spin_lock(&rpcb_clnt_lock);
> + if (--rpcb_users == 0) {
> + rpcb_local_clnt = NULL;
> + rpcb_local_clnt4 = NULL;
> + }
> + shutdown = !rpcb_users;
> + spin_unlock(&rpcb_clnt_lock);
> +
> + if (shutdown) {
> + /*
> + * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
> + */
> + if (clnt4)
> + rpc_shutdown_client(clnt4);
> + if (clnt)
> + rpc_shutdown_client(clnt);
> + }
> + return;
I'm removing this before applying...
> +}
> +
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@netapp.com
www.netapp.com
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