From: mvs <mvs@openbsd.org>
Date: Tue, 16 May 2023 19:36:00 +0000 (+0000)
Subject: Introduce temporary PR_MPSYSCTL flag to mark (*pr_sysctl)() handler MP
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=df71082dc8b610585991393266cb6deb2a4bea37;p=openbsd

Introduce temporary PR_MPSYSCTL flag to mark (*pr_sysctl)() handler MP
safe. We have may of them, so use flag instead of pushing kernel lock
within.

Unlock ip_sysctl(). Still take kernel lock within IPCTL_MRTSTATS case.
It looks like `mrtstat' protection is inconsistent, so keep locking as
it was. Since `mrtstat' are counters, it make sense to rework them into
per CPU counters with separate diffs.

Feedback and ok from bluhm@
---

diff --git a/sys/kern/uipc_domain.c b/sys/kern/uipc_domain.c
index 3b5c0bbbc9a..aa38e09d03a 100644
--- a/sys/kern/uipc_domain.c
+++ b/sys/kern/uipc_domain.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_domain.c,v 1.61 2023/05/04 09:40:36 mvs Exp $	*/
+/*	$OpenBSD: uipc_domain.c,v 1.62 2023/05/16 19:36:00 mvs Exp $	*/
 /*	$NetBSD: uipc_domain.c,v 1.14 1996/02/09 19:00:44 christos Exp $	*/
 
 /*
@@ -244,10 +244,12 @@ net_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 	protocol = name[1];
 	for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
 		if (pr->pr_protocol == protocol && pr->pr_sysctl) {
-			KERNEL_LOCK();
+			if ((pr->pr_flags & PR_MPSYSCTL) == 0)
+				KERNEL_LOCK();
 			error = (*pr->pr_sysctl)(name + 2, namelen - 2,
 			    oldp, oldlenp, newp, newlen);
-			KERNEL_UNLOCK();
+			if ((pr->pr_flags & PR_MPSYSCTL) == 0)
+				KERNEL_UNLOCK();
 			return (error);
 		}
 	return (ENOPROTOOPT);
diff --git a/sys/netinet/in_proto.c b/sys/netinet/in_proto.c
index c4087a7a993..2a49df55c5d 100644
--- a/sys/netinet/in_proto.c
+++ b/sys/netinet/in_proto.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in_proto.c,v 1.99 2022/08/15 09:11:38 mvs Exp $	*/
+/*	$OpenBSD: in_proto.c,v 1.100 2023/05/16 19:36:00 mvs Exp $	*/
 /*	$NetBSD: in_proto.c,v 1.14 1996/02/18 18:58:32 christos Exp $	*/
 
 /*
@@ -177,6 +177,7 @@ u_char ip_protox[IPPROTO_MAX];
 const struct protosw inetsw[] = {
 {
   .pr_domain	= &inetdomain,
+  .pr_flags	= PR_MPSYSCTL,
   .pr_init	= ip_init,
   .pr_slowtimo	= ip_slowtimo,
   .pr_sysctl	= ip_sysctl
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 42c1c72d78d..cfa703cca3e 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_input.c,v 1.383 2023/04/05 21:51:47 bluhm Exp $	*/
+/*	$OpenBSD: ip_input.c,v 1.384 2023/05/16 19:36:00 mvs Exp $	*/
 /*	$NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $	*/
 
 /*
@@ -1704,8 +1704,11 @@ ip_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 		return (ip_sysctl_ipstat(oldp, oldlenp, newp));
 #ifdef MROUTING
 	case IPCTL_MRTSTATS:
-		return (sysctl_rdstruct(oldp, oldlenp, newp,
-		    &mrtstat, sizeof(mrtstat)));
+		KERNEL_LOCK();
+		error = sysctl_rdstruct(oldp, oldlenp, newp,
+		    &mrtstat, sizeof(mrtstat));
+		KERNEL_UNLOCK();
+		return (error);
 	case IPCTL_MRTMFC:
 		if (newp)
 			return (EPERM);
diff --git a/sys/sys/protosw.h b/sys/sys/protosw.h
index 0109c076039..d96fe610a4a 100644
--- a/sys/sys/protosw.h
+++ b/sys/sys/protosw.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: protosw.h,v 1.59 2022/11/26 17:52:35 mvs Exp $	*/
+/*	$OpenBSD: protosw.h,v 1.60 2023/05/16 19:36:00 mvs Exp $	*/
 /*	$NetBSD: protosw.h,v 1.10 1996/04/09 20:55:32 cgd Exp $	*/
 
 /*-
@@ -123,14 +123,16 @@ struct protosw {
  * PR_ADDR requires PR_ATOMIC;
  * PR_ADDR and PR_CONNREQUIRED are mutually exclusive.
  */
-#define	PR_ATOMIC	0x01		/* exchange atomic messages only */
-#define	PR_ADDR		0x02		/* addresses given with messages */
-#define	PR_CONNREQUIRED	0x04		/* connection required by protocol */
-#define	PR_WANTRCVD	0x08		/* want PRU_RCVD calls */
-#define	PR_RIGHTS	0x10		/* passes capabilities */
-#define	PR_ABRTACPTDIS	0x20		/* abort on accept(2) to disconnected
+#define	PR_ATOMIC	0x0001		/* exchange atomic messages only */
+#define	PR_ADDR		0x0002		/* addresses given with messages */
+#define	PR_CONNREQUIRED	0x0004		/* connection required by protocol */
+#define	PR_WANTRCVD	0x0008		/* want PRU_RCVD calls */
+#define	PR_RIGHTS	0x0010		/* passes capabilities */
+#define	PR_ABRTACPTDIS	0x0020		/* abort on accept(2) to disconnected
 					   socket */
-#define	PR_SPLICE	0x40		/* socket splicing is possible */
+#define	PR_SPLICE	0x0040		/* socket splicing is possible */
+#define	PR_MPSYSCTL	0x0080		/* (*pr_sysctl)() doesn't require
+					   kernel lock */
 
 /*
  * The arguments to usrreq are: