-/* $OpenBSD: uipc_usrreq.c,v 1.159 2021/12/07 01:19:47 mvs Exp $ */
+/* $OpenBSD: uipc_usrreq.c,v 1.160 2021/12/26 23:41:41 mvs Exp $ */
/* $NetBSD: uipc_usrreq.c,v 1.18 1996/02/09 19:00:50 christos Exp $ */
/*
void uipc_setaddr(const struct unpcb *, struct mbuf *);
void unp_discard(struct fdpass *, int);
-void unp_mark(struct fdpass *, int);
+void unp_remove_gcrefs(struct fdpass *, int);
+void unp_restore_gcrefs(struct fdpass *, int);
void unp_scan(struct mbuf *, void (*)(struct fdpass *, int));
int unp_nam2sun(struct mbuf *, struct sockaddr_un **, size_t *);
}
rw_exit_write(&unp_df_lock);
+ nunref = 0;
+
rw_enter_write(&unp_gc_lock);
- unp_defer = 0;
- LIST_FOREACH(unp, &unp_head, unp_link)
+
+ /*
+ * Determine sockets which may be prospectively dead. Such
+ * sockets have their `unp_msgcount' equal to the `f_count'.
+ * If `unp_msgcount' is 0, the socket has not been passed
+ * and can't be unreferenced.
+ */
+ LIST_FOREACH(unp, &unp_head, unp_link) {
unp->unp_gcflags = 0;
+
+ if (unp->unp_msgcount == 0)
+ continue;
+ if ((fp = unp->unp_file) == NULL)
+ continue;
+ if (fp->f_count == unp->unp_msgcount) {
+ unp->unp_gcflags |= UNP_GCDEAD;
+ unp->unp_gcrefs = unp->unp_msgcount;
+ nunref++;
+ }
+ }
+
+ /*
+ * Scan all sockets previously marked as dead. Remove
+ * the `unp_gcrefs' reference each socket holds on any
+ * dead socket in its buffer.
+ */
+ LIST_FOREACH(unp, &unp_head, unp_link) {
+ if ((unp->unp_gcflags & UNP_GCDEAD) == 0)
+ continue;
+ so = unp->unp_socket;
+ solock(so);
+ unp_scan(so->so_rcv.sb_mb, unp_remove_gcrefs);
+ sounlock(so, SL_LOCKED);
+ }
+
+ /*
+ * If the dead socket has `unp_gcrefs' reference counter
+ * greater than 0, it can't be unreferenced. Mark it as
+ * alive and increment the `unp_gcrefs' reference for each
+ * dead socket within its buffer. Repeat this until we
+ * have no new alive sockets found.
+ */
do {
- nunref = 0;
+ unp_defer = 0;
+
LIST_FOREACH(unp, &unp_head, unp_link) {
- fp = unp->unp_file;
- if (unp->unp_gcflags & UNP_GCDEFER) {
- /*
- * This socket is referenced by another
- * socket which is known to be live,
- * so it's certainly live.
- */
- unp->unp_gcflags &= ~UNP_GCDEFER;
- unp_defer--;
- } else if (unp->unp_gcflags & UNP_GCMARK) {
- /* marked as live in previous pass */
+ if ((unp->unp_gcflags & UNP_GCDEAD) == 0)
+ continue;
+ if (unp->unp_gcrefs == 0)
continue;
- } else if (fp == NULL) {
- /* not being passed, so can't be in loop */
- } else if (fp->f_count == 0) {
- /*
- * Already being closed, let normal close
- * path take its course
- */
- } else {
- /*
- * Unreferenced by other sockets so far,
- * so if all the references (f_count) are
- * from passing (unp_msgcount) then this
- * socket is prospectively dead
- */
- if (fp->f_count == unp->unp_msgcount) {
- nunref++;
- unp->unp_gcflags |= UNP_GCDEAD;
- continue;
- }
- }
- /*
- * This is the first time we've seen this socket on
- * the mark pass and known it has a live reference,
- * so mark it, then scan its receive buffer for
- * sockets and note them as deferred (== referenced,
- * but not yet marked).
- */
- unp->unp_gcflags |= UNP_GCMARK;
+ unp->unp_gcflags &= ~UNP_GCDEAD;
so = unp->unp_socket;
solock(so);
- unp_scan(so->so_rcv.sb_mb, unp_mark);
+ unp_scan(so->so_rcv.sb_mb, unp_restore_gcrefs);
sounlock(so, SL_LOCKED);
+
+ KASSERT(nunref > 0);
+ nunref--;
}
- } while (unp_defer);
+ } while (unp_defer > 0);
/*
* If there are any unreferenced sockets, then for each dispose
}
}
}
+
unp_gcing = 0;
unlock:
rw_exit_write(&unp_gc_lock);
}
void
-unp_mark(struct fdpass *rp, int nfds)
+unp_discard(struct fdpass *rp, int nfds)
+{
+ struct unp_deferral *defer;
+
+ /* copy the file pointers to a deferral structure */
+ defer = malloc(sizeof(*defer) + sizeof(*rp) * nfds, M_TEMP, M_WAITOK);
+ defer->ud_n = nfds;
+ memcpy(&defer->ud_fp[0], rp, sizeof(*rp) * nfds);
+ memset(rp, 0, sizeof(*rp) * nfds);
+
+ rw_enter_write(&unp_df_lock);
+ SLIST_INSERT_HEAD(&unp_deferred, defer, ud_link);
+ rw_exit_write(&unp_df_lock);
+
+ task_add(systqmp, &unp_gc_task);
+}
+
+void
+unp_remove_gcrefs(struct fdpass *rp, int nfds)
{
struct unpcb *unp;
int i;
for (i = 0; i < nfds; i++) {
if (rp[i].fp == NULL)
continue;
-
- unp = fptounp(rp[i].fp);
- if (unp == NULL)
- continue;
-
- if (unp->unp_gcflags & (UNP_GCMARK|UNP_GCDEFER))
+ if ((unp = fptounp(rp[i].fp)) == NULL)
continue;
-
- unp_defer++;
- unp->unp_gcflags |= UNP_GCDEFER;
- unp->unp_gcflags &= ~UNP_GCDEAD;
+ if (unp->unp_gcflags & UNP_GCDEAD) {
+ KASSERT(unp->unp_gcrefs > 0);
+ unp->unp_gcrefs--;
+ }
}
}
void
-unp_discard(struct fdpass *rp, int nfds)
+unp_restore_gcrefs(struct fdpass *rp, int nfds)
{
- struct unp_deferral *defer;
-
- /* copy the file pointers to a deferral structure */
- defer = malloc(sizeof(*defer) + sizeof(*rp) * nfds, M_TEMP, M_WAITOK);
- defer->ud_n = nfds;
- memcpy(&defer->ud_fp[0], rp, sizeof(*rp) * nfds);
- memset(rp, 0, sizeof(*rp) * nfds);
+ struct unpcb *unp;
+ int i;
- rw_enter_write(&unp_df_lock);
- SLIST_INSERT_HEAD(&unp_deferred, defer, ud_link);
- rw_exit_write(&unp_df_lock);
+ rw_assert_wrlock(&unp_gc_lock);
- task_add(systqmp, &unp_gc_task);
+ for (i = 0; i < nfds; i++) {
+ if (rp[i].fp == NULL)
+ continue;
+ if ((unp = fptounp(rp[i].fp)) == NULL)
+ continue;
+ if (unp->unp_gcflags & UNP_GCDEAD) {
+ unp->unp_gcrefs++;
+ unp_defer++;
+ }
+ }
}
int
projects / openbsd / commitdiff