Mfp4 CH=177274,177280,177284-177285,177297,177324-177325

  VNET socket push back:
  try to minimize the number of places where we have to switch vnets
  and narrow down the time we stay switched.  Add assertions to the
  socket code to catch possibly unset vnets as seen in r204147.

  While this reduces the number of vnet recursion in some places like
  NFS, POSIX local sockets and some netgraph, .. recursions are
  impossible to fix.

  The current expectations are documented at the beginning of
  uipc_socket.c along with the other information there.

  Sponsored by: The FreeBSD Foundation
  Sponsored by: CK Software GmbH
  Reviewed by:  jhb
  Tested by:    zec

Tested by:	Mikolaj Golub (to.my.trociny gmail.com)
MFC after:	2 weeks

1 files changed, 78 insertions, 20 deletions

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 738bef9..54a050f 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -92,6 +92,12 @@
  * from a listen queue to a file descriptor, in order to prevent garbage
  * collection of the socket at an untimely moment.  For a number of reasons,
  * these interfaces are not preferred, and should be avoided.
+ * 
+ * NOTE: With regard to VNETs the general rule is that callers do not set
+ * curvnet. Exceptions to this rule include soabort(), sodisconnect(),
+ * sofree() (and with that sorele(), sotryfree()), as well as sonewconn()
+ * and sorflush(), which are usually called from a pre-set VNET context.
+ * sopoll() currently does not need a VNET context to be set.
  */
 
 #include <sys/cdefs.h>
@@ -175,6 +181,10 @@ int	maxsockets;
 MALLOC_DEFINE(M_SONAME, "soname", "socket name");
 MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");
 
+#define	VNET_SO_ASSERT(so)						\
+	VNET_ASSERT(curvnet != NULL,					\
+	    ("%s:%d curvnet is NULL, so=%p", __func__, __LINE__, (so)));
+
 static int somaxconn = SOMAXCONN;
 static int sysctl_somaxconn(SYSCTL_HANDLER_ARGS);
 /* XXX: we dont have SYSCTL_USHORT */
@@ -295,6 +305,8 @@ soalloc(struct vnet *vnet)
 	so->so_gencnt = ++so_gencnt;
 	++numopensockets;
 #ifdef VIMAGE
+	VNET_ASSERT(vnet != NULL, ("%s:%d vnet is NULL, so=%p",
+	    __func__, __LINE__, so));
 	vnet->vnet_sockcnt++;
 	so->so_vnet = vnet;
 #endif
@@ -318,6 +330,8 @@ sodealloc(struct socket *so)
 	so->so_gencnt = ++so_gencnt;
 	--numopensockets;	/* Could be below, but faster here. */
 #ifdef VIMAGE
+	VNET_ASSERT(so->so_vnet != NULL, ("%s:%d so_vnet is NULL, so=%p",
+	    __func__, __LINE__, so));
 	so->so_vnet->vnet_sockcnt--;
 #endif
 	mtx_unlock(&so_global_mtx);
@@ -457,6 +471,7 @@ sonewconn(struct socket *head, int connstatus)
 #endif
 	knlist_init_mtx(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv));
 	knlist_init_mtx(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd));
+	VNET_SO_ASSERT(head);
 	if (soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat) ||
 	    (*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL)) {
 		sodealloc(so);
@@ -531,8 +546,12 @@ sobind(struct socket *so, struct sockaddr *nam, struct thread *td)
 int
 solisten(struct socket *so, int backlog, struct thread *td)
 {
+	int error;
 
-	return ((*so->so_proto->pr_usrreqs->pru_listen)(so, backlog, td));
+	CURVNET_SET(so->so_vnet);
+	error = (*so->so_proto->pr_usrreqs->pru_listen)(so, backlog, td);
+	CURVNET_RESTORE();
+	return error;
 }
 
 int
@@ -620,6 +639,7 @@ sofree(struct socket *so)
 	SOCK_UNLOCK(so);
 	ACCEPT_UNLOCK();
 
+	VNET_SO_ASSERT(so);
 	if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
 		(*pr->pr_domain->dom_dispose)(so->so_rcv.sb_mb);
 	if (pr->pr_usrreqs->pru_detach != NULL)
@@ -749,6 +769,7 @@ soabort(struct socket *so)
 	KASSERT(so->so_state & SS_NOFDREF, ("soabort: !SS_NOFDREF"));
 	KASSERT((so->so_state & SQ_COMP) == 0, ("soabort: SQ_COMP"));
 	KASSERT((so->so_state & SQ_INCOMP) == 0, ("soabort: SQ_INCOMP"));
+	VNET_SO_ASSERT(so);
 
 	if (so->so_proto->pr_usrreqs->pru_abort != NULL)
 		(*so->so_proto->pr_usrreqs->pru_abort)(so);
@@ -766,7 +787,10 @@ soaccept(struct socket *so, struct sockaddr **nam)
 	KASSERT((so->so_state & SS_NOFDREF) != 0, ("soaccept: !NOFDREF"));
 	so->so_state &= ~SS_NOFDREF;
 	SOCK_UNLOCK(so);
+
+	CURVNET_SET(so->so_vnet);
 	error = (*so->so_proto->pr_usrreqs->pru_accept)(so, nam);
+	CURVNET_RESTORE();
 	return (error);
 }
 
@@ -804,8 +828,12 @@ soconnect(struct socket *so, struct sockaddr *nam, struct thread *td)
 int
 soconnect2(struct socket *so1, struct socket *so2)
 {
+	int error;
 
-	return ((*so1->so_proto->pr_usrreqs->pru_connect2)(so1, so2));
+	CURVNET_SET(so1->so_vnet);
+	error = (*so1->so_proto->pr_usrreqs->pru_connect2)(so1, so2);
+	CURVNET_RESTORE();
+	return (error);
 }
 
 int
@@ -817,6 +845,7 @@ sodisconnect(struct socket *so)
 		return (ENOTCONN);
 	if (so->so_state & SS_ISDISCONNECTING)
 		return (EALREADY);
+	VNET_SO_ASSERT(so);
 	error = (*so->so_proto->pr_usrreqs->pru_disconnect)(so);
 	return (error);
 }
@@ -1080,6 +1109,7 @@ sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio,
 	 * there are probably other places that this also happens.  We must
 	 * rethink this.
 	 */
+	VNET_SO_ASSERT(so);
 	error = (*so->so_proto->pr_usrreqs->pru_send)(so,
 	    (flags & MSG_OOB) ? PRUS_OOB :
 	/*
@@ -1267,6 +1297,7 @@ restart:
 			 * places that this also happens.  We must rethink
 			 * this.
 			 */
+			VNET_SO_ASSERT(so);
 			error = (*so->so_proto->pr_usrreqs->pru_send)(so,
 			    (flags & MSG_OOB) ? PRUS_OOB :
 			/*
@@ -1333,6 +1364,7 @@ soreceive_rcvoob(struct socket *so, struct uio *uio, int flags)
 	int error;
 
 	KASSERT(flags & MSG_OOB, ("soreceive_rcvoob: (flags & MSG_OOB) == 0"));
+	VNET_SO_ASSERT(so);
 
 	m = m_get(M_WAIT, MT_DATA);
 	error = (*pr->pr_usrreqs->pru_rcvoob)(so, m, flags & MSG_PEEK);
@@ -1441,8 +1473,10 @@ soreceive_generic(struct socket *so, struct sockaddr **psa, struct uio *uio,
 	if (mp != NULL)
 		*mp = NULL;
 	if ((pr->pr_flags & PR_WANTRCVD) && (so->so_state & SS_ISCONFIRMING)
-	    && uio->uio_resid)
+	    && uio->uio_resid) {
+		VNET_SO_ASSERT(so);
 		(*pr->pr_usrreqs->pru_rcvd)(so, 0);
+	}
 
 	error = sblock(&so->so_rcv, SBLOCKWAIT(flags));
 	if (error)
@@ -1589,6 +1623,7 @@ dontblock:
 			cm->m_next = NULL;
 			if (pr->pr_domain->dom_externalize != NULL) {
 				SOCKBUF_UNLOCK(&so->so_rcv);
+				VNET_SO_ASSERT(so);
 				error = (*pr->pr_domain->dom_externalize)
 				    (cm, controlp);
 				SOCKBUF_LOCK(&so->so_rcv);
@@ -1804,6 +1839,7 @@ dontblock:
 			 */
 			if (pr->pr_flags & PR_WANTRCVD) {
 				SOCKBUF_UNLOCK(&so->so_rcv);
+				VNET_SO_ASSERT(so);
 				(*pr->pr_usrreqs->pru_rcvd)(so, flags);
 				SOCKBUF_LOCK(&so->so_rcv);
 			}
@@ -1850,6 +1886,7 @@ dontblock:
 		if (!(flags & MSG_SOCALLBCK) &&
 		    (pr->pr_flags & PR_WANTRCVD)) {
 			SOCKBUF_UNLOCK(&so->so_rcv);
+			VNET_SO_ASSERT(so);
 			(*pr->pr_usrreqs->pru_rcvd)(so, flags);
 			SOCKBUF_LOCK(&so->so_rcv);
 		}
@@ -2046,6 +2083,7 @@ deliver:
 		    (((flags & MSG_WAITALL) && uio->uio_resid > 0) ||
 		     !(flags & MSG_SOCALLBCK))) {
 			SOCKBUF_UNLOCK(sb);
+			VNET_SO_ASSERT(so);
 			(*so->so_proto->pr_usrreqs->pru_rcvd)(so, flags);
 			SOCKBUF_LOCK(sb);
 		}
@@ -2256,9 +2294,13 @@ int
 soreceive(struct socket *so, struct sockaddr **psa, struct uio *uio,
     struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
 {
+	int error;
 
-	return (so->so_proto->pr_usrreqs->pru_soreceive(so, psa, uio, mp0,
+	CURVNET_SET(so->so_vnet);
+	error = (so->so_proto->pr_usrreqs->pru_soreceive(so, psa, uio, mp0,
 	    controlp, flagsp));
+	CURVNET_RESTORE();
+	return (error);
 }
 
 int
@@ -2269,17 +2311,19 @@ soshutdown(struct socket *so, int how)
 
 	if (!(how == SHUT_RD || how == SHUT_WR || how == SHUT_RDWR))
 		return (EINVAL);
+
+	CURVNET_SET(so->so_vnet);
 	if (pr->pr_usrreqs->pru_flush != NULL) {
 	        (*pr->pr_usrreqs->pru_flush)(so, how);
 	}
 	if (how != SHUT_WR)
 		sorflush(so);
 	if (how != SHUT_RD) {
-		CURVNET_SET(so->so_vnet);
 		error = (*pr->pr_usrreqs->pru_shutdown)(so);
 		CURVNET_RESTORE();
 		return (error);
 	}
+	CURVNET_RESTORE();
 	return (0);
 }
 
@@ -2290,6 +2334,8 @@ sorflush(struct socket *so)
 	struct protosw *pr = so->so_proto;
 	struct sockbuf asb;
 
+	VNET_SO_ASSERT(so);
+
 	/*
 	 * In order to avoid calling dom_dispose with the socket buffer mutex
 	 * held, and in order to generally avoid holding the lock for a long
@@ -2303,7 +2349,6 @@ sorflush(struct socket *so)
 	 * socket buffer.  Don't let our acquire be interrupted by a signal
 	 * despite any existing socket disposition on interruptable waiting.
 	 */
-	CURVNET_SET(so->so_vnet);
 	socantrcvmore(so);
 	(void) sblock(sb, SBL_WAIT | SBL_NOINTR);
 
@@ -2327,7 +2372,6 @@ sorflush(struct socket *so)
 	if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
 		(*pr->pr_domain->dom_dispose)(asb.sb_mb);
 	sbrelease_internal(&asb, so);
-	CURVNET_RESTORE();
 }
 
 /*
@@ -2392,11 +2436,14 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 	struct mac extmac;
 #endif
 
+	CURVNET_SET(so->so_vnet);
 	error = 0;
 	if (sopt->sopt_level != SOL_SOCKET) {
-		if (so->so_proto && so->so_proto->pr_ctloutput)
-			return ((*so->so_proto->pr_ctloutput)
-				  (so, sopt));
+		if (so->so_proto && so->so_proto->pr_ctloutput) {
+			error = (*so->so_proto->pr_ctloutput)(so, sopt);
+			CURVNET_RESTORE();
+			return (error);
+		}
 		error = ENOPROTOOPT;
 	} else {
 		switch (sopt->sopt_name) {
@@ -2592,6 +2639,7 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 		}
 	}
 bad:
+	CURVNET_RESTORE();
 	return (error);
 }
 
@@ -2635,13 +2683,15 @@ sogetopt(struct socket *so, struct sockopt *sopt)
 	struct mac extmac;
 #endif
 
+	CURVNET_SET(so->so_vnet);
 	error = 0;
 	if (sopt->sopt_level != SOL_SOCKET) {
-		if (so->so_proto && so->so_proto->pr_ctloutput) {
-			return ((*so->so_proto->pr_ctloutput)
-				  (so, sopt));
-		} else
-			return (ENOPROTOOPT);
+		if (so->so_proto && so->so_proto->pr_ctloutput)
+			error = (*so->so_proto->pr_ctloutput)(so, sopt);
+		else
+			error = ENOPROTOOPT;
+		CURVNET_RESTORE();
+		return (error);
 	} else {
 		switch (sopt->sopt_name) {
 #ifdef INET
@@ -2725,11 +2775,11 @@ integer:
 			error = sooptcopyin(sopt, &extmac, sizeof(extmac),
 			    sizeof(extmac));
 			if (error)
-				return (error);
+				goto bad;
 			error = mac_getsockopt_label(sopt->sopt_td->td_ucred,
 			    so, &extmac);
 			if (error)
-				return (error);
+				goto bad;
 			error = sooptcopyout(sopt, &extmac, sizeof extmac);
 #else
 			error = EOPNOTSUPP;
@@ -2741,11 +2791,11 @@ integer:
 			error = sooptcopyin(sopt, &extmac, sizeof(extmac),
 			    sizeof(extmac));
 			if (error)
-				return (error);
+				goto bad;
 			error = mac_getsockopt_peerlabel(
 			    sopt->sopt_td->td_ucred, so, &extmac);
 			if (error)
-				return (error);
+				goto bad;
 			error = sooptcopyout(sopt, &extmac, sizeof extmac);
 #else
 			error = EOPNOTSUPP;
@@ -2768,8 +2818,12 @@ integer:
 			error = ENOPROTOOPT;
 			break;
 		}
-		return (error);
 	}
+#ifdef MAC
+bad:
+#endif
+	CURVNET_RESTORE();
+	return (error);
 }
 
 /* XXX; prepare mbuf for (__FreeBSD__ < 3) routines. */
@@ -2903,6 +2957,10 @@ sopoll(struct socket *so, int events, struct ucred *active_cred,
     struct thread *td)
 {
 
+	/*
+	 * We do not need to set or assert curvnet as long as everyone uses
+	 * sopoll_generic().
+	 */
 	return (so->so_proto->pr_usrreqs->pru_sopoll(so, events, active_cred,
 	    td));
 }