svc: Make svc_send transport neutral

Move the sk_mutex field to the transport independent svc_xprt structure.
Now all the fields that svc_send touches are transport neutral. Change the
svc_send function to use the transport independent svc_xprt directly instead
of the transport dependent svc_sock 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>

include/linux/sunrpc/svc_xprt.h

@@ -54,6 +54,7 @@ struct svc_xprt {
 	struct svc_pool		*xpt_pool;	/* current pool iff queued */
 	struct svc_serv		*xpt_server;	/* service for transport */
 	atomic_t    	    	xpt_reserved;	/* space on outq that is rsvd */
+	struct mutex		xpt_mutex;	/* to serialize sending data */
 };
 
 int	svc_reg_xprt_class(struct svc_xprt_class *);

include/linux/sunrpc/svcsock.h

@@ -24,7 +24,6 @@ struct svc_sock {
 						 * sk_info_authunix */
 	struct list_head	sk_deferred;	/* deferred requests that need to
 						 * be revisted */
-	struct mutex		sk_mutex;	/* to serialize sending data */
 
 	/* We keep the old state_change and data_ready CB's here */
 	void			(*sk_ostate)(struct sock *);

net/sunrpc/svc_xprt.c

@@ -99,6 +99,7 @@ void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
 	xprt->xpt_server = serv;
 	INIT_LIST_HEAD(&xprt->xpt_list);
 	INIT_LIST_HEAD(&xprt->xpt_ready);
+	mutex_init(&xprt->xpt_mutex);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_init);
 

net/sunrpc/svcsock.c

@@ -1632,15 +1632,13 @@ svc_drop(struct svc_rqst *rqstp)
 int
 svc_send(struct svc_rqst *rqstp)
 {
-	struct svc_sock	*svsk;
+	struct svc_xprt	*xprt;
 	int		len;
 	struct xdr_buf	*xb;
 
-	if ((svsk = rqstp->rq_sock) == NULL) {
-		printk(KERN_WARNING "NULL socket pointer in %s:%d\n",
-				__FILE__, __LINE__);
+	xprt = rqstp->rq_xprt;
+	if (!xprt)
 		return -EFAULT;
-	}
 
 	/* release the receive skb before sending the reply */
 	rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
@@ -1651,13 +1649,13 @@ svc_send(struct svc_rqst *rqstp)
 		xb->page_len +
 		xb->tail[0].iov_len;
 
-	/* Grab svsk->sk_mutex to serialize outgoing data. */
-	mutex_lock(&svsk->sk_mutex);
-	if (test_bit(XPT_DEAD, &svsk->sk_xprt.xpt_flags))
+	/* Grab mutex to serialize outgoing data. */
+	mutex_lock(&xprt->xpt_mutex);
+	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
 		len = -ENOTCONN;
 	else
-		len = svsk->sk_xprt.xpt_ops->xpo_sendto(rqstp);
-	mutex_unlock(&svsk->sk_mutex);
+		len = xprt->xpt_ops->xpo_sendto(rqstp);
+	mutex_unlock(&xprt->xpt_mutex);
 	svc_sock_release(rqstp);
 
 	if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
@@ -1759,7 +1757,6 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
 	svsk->sk_lastrecv = get_seconds();
 	spin_lock_init(&svsk->sk_lock);
 	INIT_LIST_HEAD(&svsk->sk_deferred);
-	mutex_init(&svsk->sk_mutex);
 
 	/* Initialize the socket */
 	if (sock->type == SOCK_DGRAM)