Turn `pflow_softc' list into SMR list.

Since the revision 1.1182 of net/pf.c netlock is not taken while
export_pflow() called from pf_purge_states(). Current locks order
requires netlock to be taken before PF_LOCK(), so there is no reason
to turn it back into this path only for optional export_pflow() call.

The `pflowif_list' foreach loop has no context switch within, so SMR
list is better than mutex(9).

Tested by Hrvoje Popovski.

ok sashan bluhm

diff --git a/sys/net/if_pflow.c b/sys/net/if_pflow.c
index 67e8282..364b0a5 100644 (file)
--- a/sys/net/if_pflow.c
+++ b/sys/net/if_pflow.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_pflow.c,v 1.102 2023/12/08 23:15:44 mvs Exp $      */
+/*     $OpenBSD: if_pflow.c,v 1.103 2023/12/11 14:25:09 mvs Exp $      */
 
 /*
  * Copyright (c) 2011 Florian Obser <florian@narrans.de>
@@ -62,7 +62,7 @@
 #define DPRINTF(x)
 #endif
 
-SLIST_HEAD(, pflow_softc) pflowif_list;
+SMR_SLIST_HEAD(, pflow_softc) pflowif_list;
 struct pflowstats       pflowstats;
 
 void   pflowattach(int);
@@ -113,7 +113,7 @@ struct if_clone     pflow_cloner =
 void
 pflowattach(int npflow)
 {
-       SLIST_INIT(&pflowif_list);
+       SMR_SLIST_INIT(&pflowif_list);
        if_clone_attach(&pflow_cloner);
 }
 
@@ -268,9 +268,8 @@ pflow_clone_create(struct if_clone *ifc, int unit)
        task_set(&pflowif->sc_outputtask, pflow_output_process, pflowif);
 
        /* Insert into list of pflows */
-       NET_LOCK();
-       SLIST_INSERT_HEAD(&pflowif_list, pflowif, sc_next);
-       NET_UNLOCK();
+       KERNEL_ASSERT_LOCKED();
+       SMR_SLIST_INSERT_HEAD_LOCKED(&pflowif_list, pflowif, sc_next);
        return (0);
 }
 
@@ -284,9 +283,12 @@ pflow_clone_destroy(struct ifnet *ifp)
 
        NET_LOCK();
        sc->sc_dying = 1;
-       SLIST_REMOVE(&pflowif_list, sc, pflow_softc, sc_next);
        NET_UNLOCK();
 
+       KERNEL_ASSERT_LOCKED();
+       SMR_SLIST_REMOVE_LOCKED(&pflowif_list, sc, pflow_softc, sc_next);
+       smr_barrier();
+
        timeout_del(&sc->sc_tmo);
        timeout_del(&sc->sc_tmo6);
        timeout_del(&sc->sc_tmo_tmpl);
@@ -812,7 +814,7 @@ export_pflow(struct pf_state *st)
 
        sk = st->key[st->direction == PF_IN ? PF_SK_WIRE : PF_SK_STACK];
 
-       SLIST_FOREACH(sc, &pflowif_list, sc_next) {
+       SMR_SLIST_FOREACH(sc, &pflowif_list, sc_next) {
                mtx_enter(&sc->sc_mtx);
                switch (sc->sc_version) {
                case PFLOW_PROTO_5:

diff --git a/sys/net/if_pflow.h b/sys/net/if_pflow.h
index 430ddb3..1aacf25 100644 (file)
--- a/sys/net/if_pflow.h
+++ b/sys/net/if_pflow.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_pflow.h,v 1.20 2023/12/08 23:13:40 mvs Exp $       */
+/*     $OpenBSD: if_pflow.h,v 1.21 2023/12/11 14:25:09 mvs Exp $       */
 
 /*
  * Copyright (c) 2008 Henning Brauer <henning@openbsd.org>
@@ -169,6 +169,8 @@ struct pflow_ipfix_flow6 {
 
 #ifdef _KERNEL
 
+#include <sys/smr.h>
+
 /*
  * Locks used to protect struct members and global data
  *       I       immutable after creation
@@ -207,7 +209,7 @@ struct pflow_softc {
                                                    mbuf */
        struct mbuf             *sc_mbuf6;      /* [m] current cumulative
                                                    mbuf */
-       SLIST_ENTRY(pflow_softc) sc_next;
+       SMR_SLIST_ENTRY(pflow_softc) sc_next;
 };
 
 extern struct pflow_softc      *pflowif;