Page MenuHomeFreeBSD
Files F150247102

D12561.diff
No OneTemporary
Actions

D12561.diff
View Options

Index: head/share/man/man9/EVENTHANDLER.9
===================================================================
--- head/share/man/man9/EVENTHANDLER.9
+++ head/share/man/man9/EVENTHANDLER.9
@@ -23,7 +23,7 @@
.\" SUCH DAMAGE.
.\" $FreeBSD$
.\"
-.Dd March 27, 2017
+.Dd October 1, 2017
.Dt EVENTHANDLER 9
.Os
.Sh NAME
@@ -37,6 +37,7 @@
.Ft eventhandler_tag
.Fn EVENTHANDLER_REGISTER name func arg priority
.Fn EVENTHANDLER_DEREGISTER name tag
+.Fn EVENTHANDLER_DEREGISTER_NOWAIT name tag
.Ft eventhandler_tag
.Fo eventhandler_register
.Fa "struct eventhandler_list *list"
@@ -50,6 +51,11 @@
.Fa "struct eventhandler_list *list"
.Fa "eventhandler_tag tag"
.Fc
+.Ft void
+.Fo eventhandler_deregister_nowait
+.Fa "struct eventhandler_list *list"
+.Fa "eventhandler_tag tag"
+.Fc
.Ft "struct eventhandler_list *"
.Fn eventhandler_find_list "const char *name"
.Ft void
@@ -121,6 +127,18 @@
.Fa tag
from the event handler named by argument
.Fa name .
+It waits until no threads are running handlers for this event before
+returning, making it safe to unload a module immediately upon return
+from this function.
+.It Fn EVENTHANDLER_DEREGISTER_NOWAIT
+This macro removes a previously registered callback associated with tag
+.Fa tag
+from the event handler named by argument
+.Fa name .
+Upon return, one or more threads could still be running the removed
+function(s), but no new calls will be made.
+To remove a handler function from within that function, use this
+version of deregister, to avoid a deadlock.
.It Fn EVENTHANDLER_INVOKE
This macro is used to invoke all the callbacks associated with event
handler
@@ -176,6 +194,21 @@
.Fn eventhandler_deregister
to remove the particular callback function.
.It Fn eventhandler_deregister
+The
+.Fn eventhandler_deregister
+function removes the callback associated with tag
+.Fa tag
+from the event handler list pointed to by
+.Fa list .
+If
+.Fa tag
+is
+.Va NULL ,
+all callback functions for the event are removed.
+This function will not return until all threads have exited from the
+removed handler callback function(s).
+This function is not safe to call from inside an event handler callback.
+.It Fn eventhandler_deregister_nowait
The
.Fn eventhandler_deregister
function removes the callback associated with tag
Index: head/sys/kern/subr_eventhandler.c
===================================================================
--- head/sys/kern/subr_eventhandler.c
+++ head/sys/kern/subr_eventhandler.c
@@ -180,8 +180,9 @@
}
#endif
-void
-eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
+static void
+_eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag,
+ bool wait)
{
struct eventhandler_entry *ep = tag;
@@ -215,9 +216,24 @@
ep->ee_priority = EHE_DEAD_PRIORITY;
}
}
- while (list->el_runcount > 0)
+ while (wait && list->el_runcount > 0)
mtx_sleep(list, &list->el_lock, 0, "evhrm", 0);
EHL_UNLOCK(list);
+}
+
+void
+eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
+{
+
+ _eventhandler_deregister(list, tag, true);
+}
+
+void
+eventhandler_deregister_nowait(struct eventhandler_list *list,
+ eventhandler_tag tag)
+{
+
+ _eventhandler_deregister(list, tag, false);
}
/*
Index: head/sys/sys/eventhandler.h
===================================================================
--- head/sys/sys/eventhandler.h
+++ head/sys/sys/eventhandler.h
@@ -141,11 +141,20 @@
if ((_el = eventhandler_find_list(#name)) != NULL) \
eventhandler_deregister(_el, tag); \
} while(0)
-
+#define EVENTHANDLER_DEREGISTER_NOWAIT(name, tag) \
+do { \
+ struct eventhandler_list *_el; \
+ \
+ if ((_el = eventhandler_find_list(#name)) != NULL) \
+ eventhandler_deregister_nowait(_el, tag); \
+} while(0)
+
eventhandler_tag eventhandler_register(struct eventhandler_list *list,
const char *name, void *func, void *arg, int priority);
void eventhandler_deregister(struct eventhandler_list *list,
+ eventhandler_tag tag);
+void eventhandler_deregister_nowait(struct eventhandler_list *list,
eventhandler_tag tag);
struct eventhandler_list *eventhandler_find_list(const char *name);
void eventhandler_prune_list(struct eventhandler_list *list);

File Metadata

Mime Type
text/plain
Expires
Tue, Mar 31, 2:41 PM (20 h, 46 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
30638846
Default Alt Text
D12561.diff (4 KB)

Event Timeline