This fixes two conditions that can incur when migration

is being done in the callout code and harmonizes the macro
use.:
1) The callout_active() will lie. Basically if a migration
   is occuring and the callout is about to expire and the
   migration has been deferred, the callout_active will no
   longer return true until after the migration. This confuses
   and breaks callers that are doing callout_init(&c, 1); such
   as TCP.
2) The migration code had a bug in it where when migrating, if
   a two calls to callout_reset came in and they both collided with
   the callout on the wheel about to run, then the second call to
   callout_reset would corrupt the list the callout wheel uses
   putting the callout thread into a endless loop.
3) Per imp, I have fixed all the macro occurance in the code that
   were for the most part being ignored.

Phabricator D1711 and looked at by lstewart and jhb and sbruno.
Reviewed by:	kostikbel, imp, adrian, hselasky
MFC after:	3 days
Sponsored by:	Netflix Inc.

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/sys/callout.h b/sys/sys/callout.h
index 1096cb2..910d652 100644
--- a/sys/sys/callout.h
+++ b/sys/sys/callout.h
@@ -64,6 +64,7 @@ struct callout_handle {
 
 #ifdef _KERNEL
 #define	callout_active(c)	((c)->c_flags & CALLOUT_ACTIVE)
+#define	callout_migrating(c)	((c)->c_flags & CALLOUT_DFRMIGRATION)
 #define	callout_deactivate(c)	((c)->c_flags &= ~CALLOUT_ACTIVE)
 #define	callout_drain(c)	_callout_stop_safe(c, 1)
 void	callout_init(struct callout *, int);