Defer the vrele() on a jail's root vnode reference from prison_free()

to a new prison_complete() task run by a task queue.  This removes
a requirement for grabbing Giant in crfree().  Embed the 'struct task'
in 'struct prison' so that we don't have to allocate memory from
prison_free() (which means we also defer the FREE()).

With this change, I believe grabbing Giant from crfree() can now be
removed, but need to check the uidinfo code paths.

To avoid header pollution, move the definition of 'struct task'
to _task.h, and recursively include from taskqueue.h and jail.h; much
preferably to all files including jail.h picking up a requirement to
include taskqueue.h.

Bumped into by:	sam
Reviewed by:	bde, tjr

1 files changed, 54 insertions, 0 deletions

diff --git a/sys/sys/_task.h b/sys/sys/_task.h
new file mode 100644
index 0000000..c5c5a68
--- /dev/null
+++ b/sys/sys/_task.h
@@ -0,0 +1,54 @@
+/*-
+ * Copyright (c) 2000 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS__TASK_H_
+#define _SYS__TASK_H_
+
+#ifndef _KERNEL
+#error "no user-servicable parts inside"
+#endif
+
+#include <sys/queue.h>
+
+/*
+ * Each task includes a function which is called from
+ * taskqueue_run().  The first argument is taken from the 'ta_context'
+ * field of struct task and the second argument is a count of how many
+ * times the task was enqueued before the call to taskqueue_run().
+ */
+typedef void task_fn_t(void *context, int pending);
+
+struct task {
+	STAILQ_ENTRY(task) ta_link;	/* link for queue */
+	int	ta_pending;		/* count times queued */
+	int	ta_priority;		/* priority of task in queue */
+	task_fn_t *ta_func;		/* task handler */
+	void	*ta_context;		/* argument for handler */
+};
+
+#endif /* !_SYS__TASK_H_ */