svc: Add a generic transport svc_create_xprt function

The svc_create_xprt function is a transport independent version
of the svc_makesock function.

Since transport instance creation contains transport dependent and
independent components, add an xpo_create transport function. The
transport implementation of this function allocates the memory for the
endpoint, implements the transport dependent initialization logic, and
calls svc_xprt_init to initialize the transport independent field (svc_xprt)
in it's data structure.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

3 files changed, 85 insertions, 15 deletions

diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 31a44f441fd1..986a5a07044b 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -10,6 +10,9 @@
 #include <linux/sunrpc/svc.h>
 
 struct svc_xprt_ops {
+        struct svc_xprt *(*xpo_create)(struct svc_serv *,
+                                       struct sockaddr *, int,
+                                       int);
         struct svc_xprt *(*xpo_accept)(struct svc_xprt *);
         int             (*xpo_has_wspace)(struct svc_xprt *);
         int             (*xpo_recvfrom)(struct svc_rqst *);
@@ -36,5 +39,6 @@ struct svc_xprt {
 int     svc_reg_xprt_class(struct svc_xprt_class *);
 void    svc_unreg_xprt_class(struct svc_xprt_class *);
 void    svc_xprt_init(struct svc_xprt_class *, struct svc_xprt *);
+int     svc_create_xprt(struct svc_serv *, char *, unsigned short, int);
 
 #endif /* SUNRPC_SVC_XPRT_H */
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index fe5270fae336..6ff5ca71602f 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -81,3 +81,40 @@ void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt)
         xprt->xpt_ops = xcl->xcl_ops;
 }
 EXPORT_SYMBOL_GPL(svc_xprt_init);
+
+int svc_create_xprt(struct svc_serv *serv, char *xprt_name, unsigned short port,
+                    int flags)
+{
+        struct svc_xprt_class *xcl;
+        int ret = -ENOENT;
+        struct sockaddr_in sin = {
+                .sin_family             = AF_INET,
+                .sin_addr.s_addr        = INADDR_ANY,
+                .sin_port               = htons(port),
+        };
+        dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
+        spin_lock(&svc_xprt_class_lock);
+        list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
+                if (strcmp(xprt_name, xcl->xcl_name) == 0) {
+                        spin_unlock(&svc_xprt_class_lock);
+                        if (try_module_get(xcl->xcl_owner)) {
+                                struct svc_xprt *newxprt;
+                                ret = 0;
+                                newxprt = xcl->xcl_ops->xpo_create
+                                        (serv,
+                                         (struct sockaddr *)&sin, sizeof(sin),
+                                         flags);
+                                if (IS_ERR(newxprt)) {
+                                        module_put(xcl->xcl_owner);
+                                        ret = PTR_ERR(newxprt);
+                                }
+                        }
+                        goto out;
+                }
+        }
+        spin_unlock(&svc_xprt_class_lock);
+        dprintk("svc: transport %s not found\n", xprt_name);
+ out:
+        return ret;
+}
+EXPORT_SYMBOL_GPL(svc_create_xprt);
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 6e9dc8f96495..9f0f6d088969 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -91,6 +91,8 @@ static void		svc_sock_free(struct svc_xprt *);
 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk);
 static int svc_deferred_recv(struct svc_rqst *rqstp);
 static struct cache_deferred_req *svc_defer(struct cache_req *req);
+static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
+                                          struct sockaddr *, int, int);
 
 /* apparently the "standard" is that clients close
  * idle connections after 5 minutes, servers after
@@ -365,6 +367,7 @@ svc_sock_put(struct svc_sock *svsk)
 {
         if (atomic_dec_and_test(&svsk->sk_inuse)) {
                 BUG_ON(!test_bit(SK_DEAD, &svsk->sk_flags));
+                module_put(svsk->sk_xprt.xpt_class->xcl_owner);
                 svsk->sk_xprt.xpt_ops->xpo_free(&svsk->sk_xprt);
         }
 }
@@ -902,7 +905,15 @@ static struct svc_xprt *svc_udp_accept(struct svc_xprt *xprt)
         return NULL;
 }
 
+static struct svc_xprt *svc_udp_create(struct svc_serv *serv,
+                                       struct sockaddr *sa, int salen,
+                                       int flags)
+{
+        return svc_create_socket(serv, IPPROTO_UDP, sa, salen, flags);
+}
+
 static struct svc_xprt_ops svc_udp_ops = {
+        .xpo_create = svc_udp_create,
         .xpo_recvfrom = svc_udp_recvfrom,
         .xpo_sendto = svc_udp_sendto,
         .xpo_release_rqst = svc_release_skb,
@@ -915,6 +926,7 @@ static struct svc_xprt_ops svc_udp_ops = {
 
 static struct svc_xprt_class svc_udp_class = {
         .xcl_name = "udp",
+        .xcl_owner = THIS_MODULE,
         .xcl_ops = &svc_udp_ops,
         .xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
 };
@@ -1384,7 +1396,15 @@ static int svc_tcp_has_wspace(struct svc_xprt *xprt)
         return 1;
 }
 
+static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
+                                       struct sockaddr *sa, int salen,
+                                       int flags)
+{
+        return svc_create_socket(serv, IPPROTO_TCP, sa, salen, flags);
+}
+
 static struct svc_xprt_ops svc_tcp_ops = {
+        .xpo_create = svc_tcp_create,
         .xpo_recvfrom = svc_tcp_recvfrom,
         .xpo_sendto = svc_tcp_sendto,
         .xpo_release_rqst = svc_release_skb,
@@ -1397,6 +1417,7 @@ static struct svc_xprt_ops svc_tcp_ops = {
 
 static struct svc_xprt_class svc_tcp_class = {
         .xcl_name = "tcp",
+        .xcl_owner = THIS_MODULE,
         .xcl_ops = &svc_tcp_ops,
         .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
 };
@@ -1573,8 +1594,14 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
         } else if (test_bit(SK_LISTENER, &svsk->sk_flags)) {
                 struct svc_xprt *newxpt;
                 newxpt = svsk->sk_xprt.xpt_ops->xpo_accept(&svsk->sk_xprt);
-                if (newxpt)
+                if (newxpt) {
+                        /*
+                         * We know this module_get will succeed because the
+                         * listener holds a reference too
+                         */
+                        __module_get(newxpt->xpt_class->xcl_owner);
                         svc_check_conn_limits(svsk->sk_server);
+                }
                 svc_sock_received(svsk);
         } else {
                 dprintk("svc: server %p, pool %u, socket %p, inuse=%d\n",
@@ -1814,8 +1841,10 @@ EXPORT_SYMBOL_GPL(svc_addsock);
 /*
  * Create socket for RPC service.
  */
-static int svc_create_socket(struct svc_serv *serv, int protocol,
-                                struct sockaddr *sin, int len, int flags)
+static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
+                                          int protocol,
+                                          struct sockaddr *sin, int len,
+                                          int flags)
 {
         struct svc_sock *svsk;
         struct socket   *sock;
@@ -1830,13 +1859,13 @@ static int svc_create_socket(struct svc_serv *serv, int protocol,
         if (protocol != IPPROTO_UDP && protocol != IPPROTO_TCP) {
                 printk(KERN_WARNING "svc: only UDP and TCP "
                                 "sockets supported\n");
-                return -EINVAL;
+                return ERR_PTR(-EINVAL);
         }
         type = (protocol == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
 
         error = sock_create_kern(sin->sa_family, type, protocol, &sock);
         if (error < 0)
-                return error;
+                return ERR_PTR(error);
 
         svc_reclassify_socket(sock);
 
@@ -1853,13 +1882,13 @@ static int svc_create_socket(struct svc_serv *serv, int protocol,
 
         if ((svsk = svc_setup_socket(serv, sock, &error, flags)) != NULL) {
                 svc_sock_received(svsk);
-                return ntohs(inet_sk(svsk->sk_sk)->sport);
+                return (struct svc_xprt *)svsk;
         }
 
 bummer:
         dprintk("svc: svc_create_socket error = %d\n", -error);
         sock_release(sock);
-        return error;
+        return ERR_PTR(error);
 }
 
 /*
@@ -1970,15 +1999,15 @@ void svc_force_close_socket(struct svc_sock *svsk)
 int svc_makesock(struct svc_serv *serv, int protocol, unsigned short port,
                         int flags)
 {
-        struct sockaddr_in sin = {
-                .sin_family             = AF_INET,
-                .sin_addr.s_addr        = INADDR_ANY,
-                .sin_port               = htons(port),
-        };
-
         dprintk("svc: creating socket proto = %d\n", protocol);
-        return svc_create_socket(serv, protocol, (struct sockaddr *) &sin,
-                                                        sizeof(sin), flags);
+        switch (protocol) {
+        case IPPROTO_TCP:
+                return svc_create_xprt(serv, "tcp", port, flags);
+        case IPPROTO_UDP:
+                return svc_create_xprt(serv, "udp", port, flags);
+        default:
+                return -EINVAL;
+        }
 }
 
 /*