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

4 files changed, 8 insertions, 14 deletions

diff --git a/sys/nfsclient/bootp_subr.c b/sys/nfsclient/bootp_subr.c
index cff72c7..9fcd03f 100644
--- a/sys/nfsclient/bootp_subr.c
+++ b/sys/nfsclient/bootp_subr.c
@@ -584,8 +584,6 @@ bootpc_call(struct bootpc_globalcontext *gctx, struct thread *td)
 	int retry;
 	const char *s;
 
-	CURVNET_SET(TD_TO_VNET(td));
-
 	/*
 	 * Create socket and set its recieve timeout.
 	 */
@@ -962,7 +960,6 @@ gotreply:
 out:
 	soclose(so);
 out0:
-	CURVNET_RESTORE();
 	return error;
 }
 
@@ -977,8 +974,6 @@ bootpc_fakeup_interface(struct bootpc_ifcontext *ifctx,
 	struct ifaddr *ifa;
 	struct sockaddr_dl *sdl;
 
-	CURVNET_SET(TD_TO_VNET(td));
-
 	error = socreate(AF_INET, &ifctx->so, SOCK_DGRAM, 0, td->td_ucred, td);
 	if (error != 0)
 		panic("nfs_boot: socreate, error=%d", error);
@@ -1053,8 +1048,6 @@ bootpc_fakeup_interface(struct bootpc_ifcontext *ifctx,
 		      ifctx->ireq.ifr_name);
 	ifctx->sdl = sdl;
 
-	CURVNET_RESTORE();
-
 	return error;
 }
 
@@ -1630,6 +1623,7 @@ bootpc_init(void)
 	/*
 	 * Find a network interface.
 	 */
+	CURVNET_SET(TD_TO_VNET(td));
 #ifdef BOOTP_WIRED_TO
 	printf("bootpc_init: wired to interface '%s'\n",
 	       __XSTRING(BOOTP_WIRED_TO));
@@ -1676,6 +1670,7 @@ bootpc_init(void)
 		ifctx = ifctx->next;
 	}
 	IFNET_RUNLOCK();
+	CURVNET_RESTORE();
 
 	if (gctx->interfaces == NULL || gctx->interfaces->ifp == NULL) {
 #ifdef BOOTP_WIRED_TO
diff --git a/sys/nfsclient/krpc_subr.c b/sys/nfsclient/krpc_subr.c
index c2a8450..0639b6c 100644
--- a/sys/nfsclient/krpc_subr.c
+++ b/sys/nfsclient/krpc_subr.c
@@ -216,8 +216,6 @@ krpc_call(struct sockaddr_in *sa, u_int prog, u_int vers, u_int func,
 	nam = mhead = NULL;
 	from = NULL;
 
-	CURVNET_SET(TD_TO_VNET(td));
-
 	/*
 	 * Create socket and set its recieve timeout.
 	 */
@@ -430,7 +428,6 @@ krpc_call(struct sockaddr_in *sa, u_int prog, u_int vers, u_int func,
 	if (mhead) m_freem(mhead);
 	if (from) free(from, M_SONAME);
 	soclose(so);
-	CURVNET_RESTORE();
 	return error;
 }
 
diff --git a/sys/nfsclient/nfs_diskless.c b/sys/nfsclient/nfs_diskless.c
index aacecff..b574945 100644
--- a/sys/nfsclient/nfs_diskless.c
+++ b/sys/nfsclient/nfs_diskless.c
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/jail.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/mount.h>
@@ -202,6 +203,7 @@ nfs_setup_diskless(void)
 		return;
 	}
 	ifa = NULL;
+	CURVNET_SET(TD_TO_VNET(curthread));
 	IFNET_RLOCK();
 	TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
@@ -213,12 +215,14 @@ nfs_setup_diskless(void)
 					  LLADDR(&ourdl),
 					  sdl->sdl_alen)) {
 				    IFNET_RUNLOCK();
+				    CURVNET_RESTORE();
 				    goto match_done;
 				}
 			}
 		}
 	}
 	IFNET_RUNLOCK();
+	CURVNET_RESTORE();
 	printf("nfs_diskless: no interface\n");
 	return;	/* no matching interface */
 match_done:
diff --git a/sys/nfsclient/nfs_vfsops.c b/sys/nfsclient/nfs_vfsops.c
index fc54ff6..3700708 100644
--- a/sys/nfsclient/nfs_vfsops.c
+++ b/sys/nfsclient/nfs_vfsops.c
@@ -428,7 +428,6 @@ nfs_mountroot(struct mount *mp)
 	char buf[128];
 	char *cp;
 
-	CURVNET_SET(TD_TO_VNET(td));
 
 #if defined(BOOTP_NFSROOT) && defined(BOOTP)
 	bootpc_init();		/* use bootp to get nfs_diskless filled in */
@@ -437,7 +436,6 @@ nfs_mountroot(struct mount *mp)
 #endif
 
 	if (nfs_diskless_valid == 0) {
-		CURVNET_RESTORE();
 		return (-1);
 	}
 	if (nfs_diskless_valid == 1)
@@ -504,10 +502,12 @@ nfs_mountroot(struct mount *mp)
 		sin.sin_family = AF_INET;
 		sin.sin_len = sizeof(sin);
                 /* XXX MRT use table 0 for this sort of thing */
+		CURVNET_SET(TD_TO_VNET(td));
 		error = rtrequest(RTM_ADD, (struct sockaddr *)&sin,
 		    (struct sockaddr *)&nd->mygateway,
 		    (struct sockaddr *)&mask,
 		    RTF_UP | RTF_GATEWAY, NULL);
+		CURVNET_RESTORE();
 		if (error)
 			panic("nfs_mountroot: RTM_ADD: %d", error);
 	}
@@ -525,7 +525,6 @@ nfs_mountroot(struct mount *mp)
 	nd->root_args.hostname = buf;
 	if ((error = nfs_mountdiskless(buf,
 	    &nd->root_saddr, &nd->root_args, td, &vp, mp)) != 0) {
-		CURVNET_RESTORE();
 		return (error);
 	}
 
@@ -539,7 +538,6 @@ nfs_mountroot(struct mount *mp)
 	    sizeof (prison0.pr_hostname));
 	mtx_unlock(&prison0.pr_mtx);
 	inittodr(ntohl(nd->root_time));
-	CURVNET_RESTORE();
 	return (0);
 }