On Tue, Jan 04, 2011 at 05:48:49AM +0000, Jukka Ruohonen wrote:
> "Do not queue functions via sysmon_taskq(9) in the pmf(9) resume hooks.
> There is a small and unlikely race when the drivers are loaded as modules;
> suspend, resume, queue a function, and immediately unload the module."
Anything against adding for instance the following to sysmon_taskq(9)? Or
better ideas how this should be handled?
- Jukka.
Index: sysmon_taskq.c
===================================================================
RCS file: /cvsroot/src/sys/dev/sysmon/sysmon_taskq.c,v
retrieving revision 1.14
diff -u -p -r1.14 sysmon_taskq.c
--- sysmon_taskq.c 5 Sep 2008 22:06:52 -0000 1.14
+++ sysmon_taskq.c 4 Jan 2011 06:17:45 -0000
@@ -209,3 +209,30 @@ sysmon_task_queue_sched(u_int pri, void
return 0;
}
+
+/*
+ * sysmon_task_queue_cancel:
+ *
+ * Cancel a scheduled task.
+ */
+int
+sysmon_task_queue_cancel(void (*func)(void *))
+{
+ struct sysmon_task *st;
+
+ if (func == NULL)
+ return EINVAL;
+
+ mutex_enter(&sysmon_task_queue_mtx);
+ TAILQ_FOREACH(st, &sysmon_task_queue, st_list) {
+ if (st->st_func == func) {
+ TAILQ_REMOVE(&sysmon_task_queue, st, st_list);
+ mutex_exit(&sysmon_task_queue_mtx);
+ free(st, M_TEMP);
+ mutex_enter(&sysmon_task_queue_mtx);
+ }
+ }
+ mutex_exit(&sysmon_task_queue_mtx);
+
+ return 0;
+}
Index: sysmon_taskq.h
===================================================================
RCS file: /cvsroot/src/sys/dev/sysmon/sysmon_taskq.h,v
retrieving revision 1.2
diff -u -p -r1.2 sysmon_taskq.h
--- sysmon_taskq.h 21 Jul 2007 23:15:17 -0000 1.2
+++ sysmon_taskq.h 4 Jan 2011 06:17:45 -0000
@@ -42,5 +42,6 @@ void sysmon_task_queue_preinit(void);
void sysmon_task_queue_init(void);
void sysmon_task_queue_fini(void);
int sysmon_task_queue_sched(u_int, void (*)(void *), void *);
+int sysmon_task_queue_cancel(void (*func)(void *));
#endif /* _DEV_SYSMON_SYSMON_TASKQ_H_ */
Index: sysmon_taskq.9
===================================================================
RCS file: /cvsroot/src/share/man/man9/sysmon_taskq.9,v
retrieving revision 1.6
diff -u -p -r1.6 sysmon_taskq.9
--- sysmon_taskq.9 26 Jan 2010 08:48:39 -0000 1.6
+++ sysmon_taskq.9 4 Jan 2011 06:18:23 -0000
@@ -43,6 +43,8 @@
.Fn sysmon_task_queue_fini "void"
.Ft int
.Fn sysmon_task_queue_sched "u_int pri" "void (*func)(void *)" "void *arg"
+.Ft int
+.Fn sysmon_task_queue_cancel "void (*func)(void *)"
.Sh DESCRIPTION
The machine-independent
.Nm
@@ -78,10 +80,15 @@ The single argument passed to
.Fa func
is specified by
.Fa arg .
+The
+.Fn sysmon_task_queue_cancel
+function can be used to cancel the execution of already scheduled function.
.Sh RETURN VALUES
-Upon successful completion,
+Both
.Fn sysmon_task_queue_sched
-returns 0.
+and
+.Fn sysmon_task_queue_cancel
+return 0 upon successful completion,
Otherwise, the following error values are returned:
.Bl -tag -width [EINVAL]
.It Bq Er EINVAL
