From 1bf93686367c8096f6a4f78a97a49a1702687cef Mon Sep 17 00:00:00 2001 From: ed Date: Wed, 12 Aug 2015 17:46:26 +0000 Subject: [PATCH] Perform cleanups in response to D3307. - Document the kern_kevent_anonymous() function. - Add assertions to ensure that we don't silently leave the kqueue linked from a file descriptor table. Reviewed by: jmg Differential Revision: https://reviews.freebsd.org/D3364 --- sys/kern/kern_event.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c index 2b43632c0b7..a4388aaf68d 100644 --- a/sys/kern/kern_event.c +++ b/sys/kern/kern_event.c @@ -975,6 +975,10 @@ kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, return (error); } +/* + * Performs a kevent() call on a temporarily created kqueue. This can be + * used to perform one-shot polling, similar to poll() and select(). + */ int kern_kevent_anonymous(struct thread *td, int nevents, struct kevent_copyops *k_ops) @@ -1831,6 +1835,8 @@ static void kqueue_destroy(struct kqueue *kq) { + KASSERT(kq->kq_fdp == NULL, + ("kqueue still attached to a file descriptor")); seldrain(&kq->kq_sel); knlist_destroy(&kq->kq_sel.si_note); mtx_destroy(&kq->kq_lock); @@ -1863,6 +1869,7 @@ kqueue_close(struct file *fp, struct thread *td) * take the sleepable lock after non-sleepable. */ fdp = kq->kq_fdp; + kq->kq_fdp = NULL; if (!sx_xlocked(FILEDESC_LOCK(fdp))) { FILEDESC_XLOCK(fdp); filedesc_unlock = 1; -- 2.45.0