this is a tiny slice off a big pfsync diff i've been working on. when
you bring pfsync down i need it to wait until all the work it's been
doing in the network stack has finished, which means i need a barrier
for all the network taskqs. that's what this implements.
a barrier per taskq would mean iterating over the taskqs and waiting for
a barrier on each one. by using a refcnt and shoving a task onto each of
them in one go, i only have to wait for the slowest one, not all
of them in series.
ok?
Index: if.c
===================================================================
RCS file: /cvs/src/sys/net/if.c,v
retrieving revision 1.696
diff -u -p -r1.696 if.c
--- if.c 14 May 2023 01:46:53 -0000 1.696
+++ if.c 19 May 2023 03:50:10 -0000
@@ -3481,3 +3481,19 @@ net_tq(unsigned int ifindex)
return (sn->sn_taskq);
}
+
+void
+net_tq_barriers(const char *wmesg)
+{
+ struct task barriers[NET_TASKQ];
+ struct refcnt r = REFCNT_INITIALIZER();
+ int i;
+
+ for (i = 0; i < nitems(barriers); i++) {
+ task_set(&barriers[i], (void (*)(void *))refcnt_rele_wake, &r);
+ refcnt_take(&r);
+ task_add(softnets[i].sn_taskq, &barriers[i]);
+ }
+
+ refcnt_finalize(&r, wmesg);
+}
Index: if.h
===================================================================
RCS file: /cvs/src/sys/net/if.h,v
retrieving revision 1.212
diff -u -p -r1.212 if.h
--- if.h 15 May 2023 16:34:56 -0000 1.212
+++ if.h 19 May 2023 03:50:10 -0000
@@ -560,6 +560,7 @@ int if_congested(void);
__dead void unhandled_af(int);
int if_setlladdr(struct ifnet *, const uint8_t *);
struct taskq * net_tq(unsigned int);
+void net_tq_barriers(const char *);
#endif /* _KERNEL */
