diff options
Diffstat (limited to 'sys/kern/uipc_usrreq.c')
| -rw-r--r-- | sys/kern/uipc_usrreq.c | 165 |
1 files changed, 96 insertions, 69 deletions
diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c index 7cb3cc39494..160ff15738d 100644 --- a/sys/kern/uipc_usrreq.c +++ b/sys/kern/uipc_usrreq.c @@ -1,4 +1,4 @@ -/* $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 $ */ /* @@ -85,7 +85,8 @@ struct unp_deferral { 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 *); @@ -1162,61 +1163,71 @@ unp_gc(void *arg __unused) } 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 @@ -1238,6 +1249,7 @@ unp_gc(void *arg __unused) } } } + unp_gcing = 0; unlock: rw_exit_write(&unp_gc_lock); @@ -1281,7 +1293,25 @@ unp_scan(struct mbuf *m0, void (*op)(struct fdpass *, int)) } 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; @@ -1291,36 +1321,33 @@ unp_mark(struct fdpass *rp, int nfds) 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 |