Take advantage of pre-existing lock-free synchronization and type stable memory

to avoid acquiring SMP locks during expensive copyout process.

3 files changed, 10 insertions, 11 deletions

diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index cb9682d..d12c899 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -840,8 +840,8 @@ tcp_notify(inp, error)
 	 * can never complete.
 	 */
 	if (tp->t_state == TCPS_ESTABLISHED &&
-	     (error == EHOSTUNREACH || error == ENETUNREACH ||
-	      error == EHOSTDOWN)) {
+	    (error == EHOSTUNREACH || error == ENETUNREACH ||
+	     error == EHOSTDOWN)) {
 		return inp;
 	} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
 	    tp->t_softerror) {
@@ -922,7 +922,6 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 	error = 0;
 	for (i = 0; i < n; i++) {
 		inp = inp_list[i];
-		INP_LOCK(inp);
 		if (inp->inp_gencnt <= gencnt) {
 			struct xtcpcb xt;
 			caddr_t inp_ppcb;
@@ -936,9 +935,9 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 				bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
 			if (inp->inp_socket)
 				sotoxsocket(inp->inp_socket, &xt.xt_socket);
+			xt.xt_inp.inp_gencnt = inp->inp_gencnt;
 			error = SYSCTL_OUT(req, &xt, sizeof xt);
 		}
-		INP_UNLOCK(inp);
 	}
 	if (!error) {
 		/*
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
index cb9682d..d12c899 100644
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -840,8 +840,8 @@ tcp_notify(inp, error)
 	 * can never complete.
 	 */
 	if (tp->t_state == TCPS_ESTABLISHED &&
-	     (error == EHOSTUNREACH || error == ENETUNREACH ||
-	      error == EHOSTDOWN)) {
+	    (error == EHOSTUNREACH || error == ENETUNREACH ||
+	     error == EHOSTDOWN)) {
 		return inp;
 	} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
 	    tp->t_softerror) {
@@ -922,7 +922,6 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 	error = 0;
 	for (i = 0; i < n; i++) {
 		inp = inp_list[i];
-		INP_LOCK(inp);
 		if (inp->inp_gencnt <= gencnt) {
 			struct xtcpcb xt;
 			caddr_t inp_ppcb;
@@ -936,9 +935,9 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 				bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
 			if (inp->inp_socket)
 				sotoxsocket(inp->inp_socket, &xt.xt_socket);
+			xt.xt_inp.inp_gencnt = inp->inp_gencnt;
 			error = SYSCTL_OUT(req, &xt, sizeof xt);
 		}
-		INP_UNLOCK(inp);
 	}
 	if (!error) {
 		/*
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index 4331770..7d2a9f3 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -531,7 +531,7 @@ udp_ctlinput(cmd, sa, vip)
                     ip->ip_src, uh->uh_sport, 0, NULL);
 		if (inp != NULL) {
 			INP_LOCK(inp);
-			if(inp->inp_socket != NULL) {
+			if (inp->inp_socket != NULL) {
 				(*notify)(inp, inetctlerrmap[cmd]);
 			}
 			INP_UNLOCK(inp);
@@ -568,8 +568,10 @@ udp_pcblist(SYSCTL_HANDLER_ARGS)
 	 * OK, now we're committed to doing something.
 	 */
 	s = splnet();
+	INP_INFO_RLOCK(&udbinfo);
 	gencnt = udbinfo.ipi_gencnt;
 	n = udbinfo.ipi_count;
+	INP_INFO_RUNLOCK(&udbinfo);
 	splx(s);
 
 	sysctl_wire_old_buffer(req, 2 * (sizeof xig)
@@ -604,7 +606,6 @@ udp_pcblist(SYSCTL_HANDLER_ARGS)
 	error = 0;
 	for (i = 0; i < n; i++) {
 		inp = inp_list[i];
-		INP_LOCK(inp);
 		if (inp->inp_gencnt <= gencnt) {
 			struct xinpcb xi;
 			xi.xi_len = sizeof xi;
@@ -612,9 +613,9 @@ udp_pcblist(SYSCTL_HANDLER_ARGS)
 			bcopy(inp, &xi.xi_inp, sizeof *inp);
 			if (inp->inp_socket)
 				sotoxsocket(inp->inp_socket, &xi.xi_socket);
+			xi.xi_inp.inp_gencnt = inp->inp_gencnt;
 			error = SYSCTL_OUT(req, &xi, sizeof xi);
 		}
-		INP_UNLOCK(inp);
 	}
 	if (!error) {
 		/*