From e6636b47d6f31b0f7a0a85d62650c28c5ebb69e8 Mon Sep 17 00:00:00 2001
From: mav <mav@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Wed, 22 Jan 2014 23:51:12 +0000
Subject: [PATCH] MFC r260036: Introduce xprt_inactive_self()  -- variant for
 use when sure that port is assigned to thread.  For example, withing receive
 handlers.  In that case the function reduces to single assignment and can
 avoid locking.

git-svn-id: svn://svn.freebsd.org/base/stable/10@261053 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 sys/rpc/svc.c    | 13 +++++++++++++
 sys/rpc/svc.h    |  1 +
 sys/rpc/svc_dg.c |  8 ++++----
 sys/rpc/svc_vc.c | 14 +++++++-------
 4 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/sys/rpc/svc.c b/sys/rpc/svc.c
index 96d011a59..f63300de0 100644
--- a/sys/rpc/svc.c
+++ b/sys/rpc/svc.c
@@ -405,6 +405,19 @@ xprt_inactive(SVCXPRT *xprt)
 	mtx_unlock(&pool->sp_lock);
 }
 
+/*
+ * Variant of xprt_inactive() for use only when sure that port is
+ * assigned to thread. For example, withing receive handlers.
+ */
+void
+xprt_inactive_self(SVCXPRT *xprt)
+{
+
+	KASSERT(xprt->xp_thread != NULL,
+	    ("xprt_inactive_self(%p) with NULL xp_thread", xprt));
+	xprt->xp_active = FALSE;
+}
+
 /*
  * Add a service program to the callout list.
  * The dispatch routine will be called when a rpc request for this
diff --git a/sys/rpc/svc.h b/sys/rpc/svc.h
index 0b2884f3e..051ebfbc7 100644
--- a/sys/rpc/svc.h
+++ b/sys/rpc/svc.h
@@ -523,6 +523,7 @@ __BEGIN_DECLS
 extern void	xprt_active(SVCXPRT *);
 extern void	xprt_inactive(SVCXPRT *);
 extern void	xprt_inactive_locked(SVCXPRT *);
+extern void	xprt_inactive_self(SVCXPRT *);
 __END_DECLS
 
 #endif
diff --git a/sys/rpc/svc_dg.c b/sys/rpc/svc_dg.c
index 861c26ec7..79f8429fa 100644
--- a/sys/rpc/svc_dg.c
+++ b/sys/rpc/svc_dg.c
@@ -196,10 +196,10 @@ svc_dg_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 		 * from racing the upcall after our soreadable() call
 		 * returns false.
 		 */
-		mtx_lock(&xprt->xp_pool->sp_lock);
+		SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
 		if (!soreadable(xprt->xp_socket))
-			xprt_inactive_locked(xprt);
-		mtx_unlock(&xprt->xp_pool->sp_lock);
+			xprt_inactive_self(xprt);
+		SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
 		sx_xunlock(&xprt->xp_lock);
 		return (FALSE);
 	}
@@ -208,7 +208,7 @@ svc_dg_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 		SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
 		soupcall_clear(xprt->xp_socket, SO_RCV);
 		SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
-		xprt_inactive(xprt);
+		xprt_inactive_self(xprt);
 		sx_xunlock(&xprt->xp_lock);
 		return (FALSE);
 	}
diff --git a/sys/rpc/svc_vc.c b/sys/rpc/svc_vc.c
index f9ff0e6f5..314091535 100644
--- a/sys/rpc/svc_vc.c
+++ b/sys/rpc/svc_vc.c
@@ -385,7 +385,7 @@ svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 		 */
 		ACCEPT_LOCK();
 		if (TAILQ_EMPTY(&xprt->xp_socket->so_comp))
-			xprt_inactive(xprt);
+			xprt_inactive_self(xprt);
 		ACCEPT_UNLOCK();
 		sx_xunlock(&xprt->xp_lock);
 		return (FALSE);
@@ -398,7 +398,7 @@ svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 			soupcall_clear(xprt->xp_socket, SO_RCV);
 		}
 		SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
-		xprt_inactive(xprt);
+		xprt_inactive_self(xprt);
 		sx_xunlock(&xprt->xp_lock);
 		return (FALSE);
 	}
@@ -667,7 +667,7 @@ svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 			if (cd->mreq == NULL || cd->resid != 0) {
 				SOCKBUF_LOCK(&so->so_rcv);
 				if (!soreadable(so))
-					xprt_inactive(xprt);
+					xprt_inactive_self(xprt);
 				SOCKBUF_UNLOCK(&so->so_rcv);
 			}
 
@@ -709,7 +709,7 @@ svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 			 */
 			SOCKBUF_LOCK(&so->so_rcv);
 			if (!soreadable(so))
-				xprt_inactive(xprt);
+				xprt_inactive_self(xprt);
 			SOCKBUF_UNLOCK(&so->so_rcv);
 			sx_xunlock(&xprt->xp_lock);
 			return (FALSE);
@@ -722,7 +722,7 @@ svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 				soupcall_clear(so, SO_RCV);
 			}
 			SOCKBUF_UNLOCK(&so->so_rcv);
-			xprt_inactive(xprt);
+			xprt_inactive_self(xprt);
 			cd->strm_stat = XPRT_DIED;
 			sx_xunlock(&xprt->xp_lock);
 			return (FALSE);
@@ -732,7 +732,7 @@ svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 			/*
 			 * EOF - the other end has closed the socket.
 			 */
-			xprt_inactive(xprt);
+			xprt_inactive_self(xprt);
 			cd->strm_stat = XPRT_DIED;
 			sx_xunlock(&xprt->xp_lock);
 			return (FALSE);
@@ -763,7 +763,7 @@ svc_vc_backchannel_recv(SVCXPRT *xprt, struct rpc_msg *msg,
 	mtx_lock(&ct->ct_lock);
 	m = cd->mreq;
 	if (m == NULL) {
-		xprt_inactive(xprt);
+		xprt_inactive_self(xprt);
 		mtx_unlock(&ct->ct_lock);
 		sx_xunlock(&xprt->xp_lock);
 		return (FALSE);
-- 
2.45.0