SUNRPC: Allow svc_reserve() to notify TCP socket that space has been freed

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

include/linux/sunrpc/svc_xprt.h

@@ -25,6 +25,7 @@ struct svc_xprt_ops {
 	void		(*xpo_detach)(struct svc_xprt *);
 	void		(*xpo_free)(struct svc_xprt *);
 	int		(*xpo_secure_port)(struct svc_rqst *);
+	void		(*xpo_adjust_wspace)(struct svc_xprt *);
 };
 
 struct svc_xprt_class {

net/sunrpc/svc_xprt.c

@@ -448,6 +448,8 @@ void svc_reserve(struct svc_rqst *rqstp, int space)
 		atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
 		rqstp->rq_reserved = space;
 
+		if (xprt->xpt_ops->xpo_adjust_wspace)
+			xprt->xpt_ops->xpo_adjust_wspace(xprt);
 		svc_xprt_enqueue(xprt);
 	}
 }

net/sunrpc/svcsock.c

@@ -475,6 +475,14 @@ static void svc_tcp_write_space(struct sock *sk)
 	svc_write_space(sk);
 }
 
+static void svc_tcp_adjust_wspace(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+	if (svc_tcp_has_wspace(xprt))
+		clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+}
+
 /*
  * See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
  */
@@ -1289,6 +1297,7 @@ static struct svc_xprt_ops svc_tcp_ops = {
 	.xpo_has_wspace = svc_tcp_has_wspace,
 	.xpo_accept = svc_tcp_accept,
 	.xpo_secure_port = svc_sock_secure_port,
+	.xpo_adjust_wspace = svc_tcp_adjust_wspace,
 };
 
 static struct svc_xprt_class svc_tcp_class = {