From 95d0d388ac9c14373708101bce1a8922f43d6386 Mon Sep 17 00:00:00 2001
From: rwatson <rwatson@FreeBSD.org>
Date: Sun, 25 Mar 2007 21:44:24 +0000
Subject: [PATCH] Replace GIANT_REQUIRED's present for socket locking with
 NET_LOCK_GIANT(). If/when someone does the necessary MPSAFEty locking for the
 NFSv4 client, the socket code is generally MPSAFE now.

Spotted by:	kris
---
 sys/rpc/rpcclnt.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/sys/rpc/rpcclnt.c b/sys/rpc/rpcclnt.c
index 04e1bce0cf5a..d666e1b4f3a8 100644
--- a/sys/rpc/rpcclnt.c
+++ b/sys/rpc/rpcclnt.c
@@ -360,15 +360,15 @@ rpcclnt_connect(rpc, td)
 		RPC_RETURN(EFAULT);
 	}
 
-	GIANT_REQUIRED;		/* XXX until socket locking done */
-
 	/* create the socket */
 	rpc->rc_so = NULL;
 
 	saddr = rpc->rc_name;
 
+	NET_LOCK_GIANT();
 	error = socreate(saddr->sa_family, &rpc->rc_so, rpc->rc_sotype,
 			 rpc->rc_soproto, td->td_ucred, td);
+	NET_UNLOCK_GIANT();
 
 	if (error) {
 		RPCDEBUG("error %d in socreate()", error);
@@ -624,13 +624,13 @@ rpcclnt_disconnect(rpc)
 {
 	struct socket  *so;
 
-	GIANT_REQUIRED;		/* XXX until socket locking done */
-
 	if (rpc->rc_so) {
 		so = rpc->rc_so;
 		rpc->rc_so = NULL;
+		NET_LOCK_GIANT();
 		soshutdown(so, 2);
 		soclose(so);
+		NET_UNLOCK_GIANT();
 	}
 }
 
@@ -678,8 +678,6 @@ rpcclnt_send(so, nam, top, rep)
 #endif
 	int error, soflags, flags;
 
-	GIANT_REQUIRED;		/* XXX until socket locking done */
-
 	if (rep) {
 		if (rep->r_flags & R_SOFTTERM) {
 			m_freem(top);
@@ -705,7 +703,14 @@ rpcclnt_send(so, nam, top, rep)
 	else
 		flags = 0;
 
+	/*
+	 * XXXRW: If/when this code becomes MPSAFE itself, Giant might have
+	 * to be conditionally acquired earlier for the stack so has to avoid
+	 * lock order reversals with any locks held over rpcclnt_send().
+	 */
+	NET_LOCK_GIANT();
 	error = sosend(so, sendnam, NULL, top, NULL, flags, td);
+	NET_UNLOCK_GIANT();
 
 	if (error) {
 		if (rep) {
@@ -763,8 +768,6 @@ rpcclnt_receive(rep, aname, mp, td)
 #endif
 	int error, sotype, rcvflg;
 
-	GIANT_REQUIRED;		/* XXX until socket locking done */
-
 	/*
 	 * Set up arguments for soreceive()
 	 */
@@ -835,7 +838,9 @@ rpcclnt_receive(rep, aname, mp, td)
 #endif
 			do {
 				rcvflg = MSG_WAITALL;
+				NET_LOCK_GIANT();
 				error = soreceive(so, NULL, &auio, NULL, NULL, &rcvflg);
+				NET_UNLOCK_GIANT();
 				if (error == EWOULDBLOCK && rep) {
 					if (rep->r_flags & R_SOFTTERM)
 						RPC_RETURN(EINTR);
@@ -868,7 +873,9 @@ rpcclnt_receive(rep, aname, mp, td)
 			auio.uio_resid = len;
 			do {
 				rcvflg = MSG_WAITALL;
+				NET_LOCK_GIANT();
 				error = soreceive(so, NULL, &auio, mp, NULL, &rcvflg);
+				NET_UNLOCK_GIANT();
 			} while (error == EWOULDBLOCK || error == EINTR ||
 				 error == ERESTART);
 			if (!error && auio.uio_resid > 0) {
@@ -894,7 +901,9 @@ rpcclnt_receive(rep, aname, mp, td)
 #endif
 			do {
 				rcvflg = 0;
+				NET_LOCK_GIANT();
 				error = soreceive(so, NULL, &auio, mp, &control, &rcvflg);
+				NET_UNLOCK_GIANT();
 				if (control)
 					m_freem(control);
 				if (error == EWOULDBLOCK && rep) {
@@ -940,8 +949,10 @@ rpcclnt_receive(rep, aname, mp, td)
 
 		do {
 			rcvflg = 0;
+			NET_LOCK_GIANT();
 			error = soreceive(so, getnam, &auio, mp, NULL, &rcvflg);
-			RPCDEBUG("soreceivce returns %d", error);
+			NET_UNLOCK_GIANT();
+			RPCDEBUG("soreceive returns %d", error);
 			if (error == EWOULDBLOCK && (rep->r_flags & R_SOFTTERM)) {
 				RPCDEBUG("wouldblock && softerm -> EINTR");
 				RPC_RETURN(EINTR);