On Fri, Dec 17, 2010 at 01:20:02PM -0500, andros@xxxxxxxxxx wrote:
> From: Andy Adamson <andros@xxxxxxxxxx>
>
> Create a new transport for the shared back channel.l Move the current sock
> create and destroy routines into the new transport ops.
>
> Reference the back channel transport across message processing (recv/send).
>
> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
> ---
> include/linux/sunrpc/svcsock.h | 1 +
> net/sunrpc/svc.c | 18 +++---
> net/sunrpc/svcsock.c | 122 +++++++++++++++++++++++++++++++++-------
> 3 files changed, 112 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
> index 1b353a7..3a45a80 100644
> --- a/include/linux/sunrpc/svcsock.h
> +++ b/include/linux/sunrpc/svcsock.h
> @@ -45,6 +45,7 @@ int svc_sock_names(struct svc_serv *serv, char *buf,
> int svc_addsock(struct svc_serv *serv, const int fd,
> char *name_return, const size_t len);
> void svc_init_xprt_sock(void);
> +void svc_init_bc_xprt_sock(void);
> void svc_cleanup_xprt_sock(void);
> struct svc_xprt *svc_sock_create(struct svc_serv *serv, int prot);
> void svc_sock_destroy(struct svc_xprt *);
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index 6359c42..3520cb3 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -488,10 +488,6 @@ svc_destroy(struct svc_serv *serv)
> if (svc_serv_is_pooled(serv))
> svc_pool_map_put();
>
> -#if defined(CONFIG_NFS_V4_1)
> - svc_sock_destroy(serv->bc_xprt);
> -#endif /* CONFIG_NFS_V4_1 */
> -
> svc_unregister(serv);
> kfree(serv->sv_pools);
> kfree(serv);
> @@ -1264,7 +1260,7 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
> {
> struct kvec *argv = &rqstp->rq_arg.head[0];
> struct kvec *resv = &rqstp->rq_res.head[0];
> - int error;
> + int ret;
>
> /* Build the svc_rqst used by the common processing routine */
> rqstp->rq_xprt = serv->bc_xprt;
> @@ -1292,12 +1288,16 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
> svc_getu32(argv); /* XID */
> svc_getnl(argv); /* CALLDIR */
>
> - error = svc_process_common(rqstp, argv, resv);
> - if (error <= 0)
> - return error;
> + /* Hold a reference to the back channel socket across the call */
> + svc_xprt_get(serv->bc_xprt);
Either we already have a reference, in which case this is unnecessary,
or we don't, in which case this is risky.
The nfs client code knows when it wants to create and destroy the
backchannel, so I think all you want is to create the svc_xprt when you
create the backchannel and then put it once when you bring it down.
--b.
> + ret = svc_process_common(rqstp, argv, resv);
> + if (ret <= 0)
> + return ret;
>
> memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
> - return bc_send(req);
> + ret = bc_send(req);
> + svc_xprt_put(serv->bc_xprt);
> + return ret;
> }
> EXPORT_SYMBOL(bc_svc_process);
> #endif /* CONFIG_NFS_V4_1 */
> diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
> index 07919e1..5875551 100644
> --- a/net/sunrpc/svcsock.c
> +++ b/net/sunrpc/svcsock.c
> @@ -66,6 +66,13 @@ static void svc_sock_free(struct svc_xprt *);
> static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
> struct net *, struct sockaddr *,
> int, int);
> +#if defined(CONFIG_NFS_V4_1)
> +static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
> + struct net *, struct sockaddr *,
> + int, int);
> +static void svc_bc_sock_free(struct svc_xprt *xprt);
> +#endif /* CONFIG_NFS_V4_1 */
> +
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> static struct lock_class_key svc_key[2];
> static struct lock_class_key svc_slock_key[2];
> @@ -1184,6 +1191,79 @@ static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
> return svc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
> }
>
> +#if defined(CONFIG_NFS_V4_1)
> +static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
> + struct net *, struct sockaddr *,
> + int, int);
> +static void svc_bc_sock_free(struct svc_xprt *xprt);
> +
> +static struct svc_xprt *svc_bc_tcp_create(struct svc_serv *serv,
> + struct net *net,
> + struct sockaddr *sa, int salen,
> + int flags)
> +{
> + return svc_bc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
> +}
> +
> +static void svc_bc_tcp_sock_detach(struct svc_xprt *xprt)
> +{
> +}
> +
> +/* These bc ops are never called. The shared fore channel is used instead */
> +static int svc_bc_tcp_recvfrom(struct svc_rqst *rqstp)
> +{
> + return 0;
> +}
> +
> +static int svc_bc_tcp_sendto(struct svc_rqst *rqstp)
> +{
> + return 0;
> +}
> +
> +static void svc_bc_tcp_prep_reply_hdr(struct svc_rqst *rqstp)
> +{
> +}
> +
> +static void svc_bc_release_skb(struct svc_rqst *rqstp)
> +{
> +}
> +
> +static int svc_bc_tcp_has_wspace(struct svc_xprt *xprt)
> +{
> + return 0;
> +}
> +
> +static struct svc_xprt *svc_bc_tcp_accept(struct svc_xprt *xprt)
> +{
> + return NULL;
> +}
> +
> +static struct svc_xprt_ops svc_tcp_bc_ops = {
> + .xpo_create = svc_bc_tcp_create,
> + .xpo_recvfrom = svc_bc_tcp_recvfrom,
> + .xpo_sendto = svc_bc_tcp_sendto,
> + .xpo_release_rqst = svc_bc_release_skb,
> + .xpo_detach = svc_bc_tcp_sock_detach,
> + .xpo_free = svc_bc_sock_free,
> + .xpo_prep_reply_hdr = svc_bc_tcp_prep_reply_hdr,
> + .xpo_has_wspace = svc_bc_tcp_has_wspace,
> + .xpo_accept = svc_bc_tcp_accept,
> +};
> +
> +static struct svc_xprt_class svc_tcp_bc_class = {
> + .xcl_name = "tcp-bc",
> + .xcl_owner = THIS_MODULE,
> + .xcl_ops = &svc_tcp_bc_ops,
> + .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
> +};
> +
> +void svc_init_bc_xprt_sock(void)
> +{
> + svc_reg_xprt_class(&svc_tcp_bc_class);
> +}
> +EXPORT_SYMBOL_GPL(svc_init_bc_xprt_sock);
> +#endif /* CONFIG_NFS_V4_1 */
> +
> static struct svc_xprt_ops svc_tcp_ops = {
> .xpo_create = svc_tcp_create,
> .xpo_recvfrom = svc_tcp_recvfrom,
> @@ -1509,41 +1589,43 @@ static void svc_sock_free(struct svc_xprt *xprt)
> kfree(svsk);
> }
>
> +#if defined(CONFIG_NFS_V4_1)
> /*
> - * Create a svc_xprt.
> - *
> - * For internal use only (e.g. nfsv4.1 backchannel).
> - * Callers should typically use the xpo_create() method.
> + * Create a back channel svc_xprt which shares the fore channel socket.
> */
> -struct svc_xprt *svc_sock_create(struct svc_serv *serv, int prot)
> +static struct svc_xprt *svc_bc_create_socket(struct svc_serv *serv,
> + int protocol,
> + struct net *net,
> + struct sockaddr *sin, int len,
> + int flags)
> {
> struct svc_sock *svsk;
> - struct svc_xprt *xprt = NULL;
> + struct svc_xprt *xprt;
> +
> + if (protocol != IPPROTO_TCP) {
> + printk(KERN_WARNING "svc: only and TCP sockets"
> + " supported on shared back channel\n");
> + return ERR_PTR(-EINVAL);
> + }
>
> - dprintk("svc: %s\n", __func__);
> svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
> if (!svsk)
> - goto out;
> + return ERR_PTR(-ENOMEM);
>
> xprt = &svsk->sk_xprt;
> - if (prot == IPPROTO_TCP)
> - svc_xprt_init(&svc_tcp_class, xprt, serv);
> - else if (prot == IPPROTO_UDP)
> - svc_xprt_init(&svc_udp_class, xprt, serv);
> - else
> - BUG();
> -out:
> - dprintk("svc: %s return %p\n", __func__, xprt);
> + svc_xprt_init(&svc_tcp_bc_class, xprt, serv);
> +
> + serv->bc_xprt = xprt;
> +
> return xprt;
> }
> -EXPORT_SYMBOL_GPL(svc_sock_create);
>
> /*
> - * Destroy a svc_sock.
> + * Free a back channel svc_sock.
> */
> -void svc_sock_destroy(struct svc_xprt *xprt)
> +static void svc_bc_sock_free(struct svc_xprt *xprt)
> {
> if (xprt)
> kfree(container_of(xprt, struct svc_sock, sk_xprt));
> }
> -EXPORT_SYMBOL_GPL(svc_sock_destroy);
> +#endif /* CONFIG_NFS_V4_1 */
> --
> 1.6.6
>
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