Add rw_wowned() interface to rwlock(9), allowing a kernel thread to

determine if it holds an exclusive rwlock reference or not.  This is
non-ideal, but recursion scenarios in the network stack currently
require it.

Approved by:	jhb

2 files changed, 8 insertions, 0 deletions

diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c
index a59de60..18e9a54 100644
--- a/sys/kern/kern_rwlock.c
+++ b/sys/kern/kern_rwlock.c
@@ -108,6 +108,13 @@ rw_sysinit(void *arg)
 	rw_init(args->ra_rw, args->ra_desc);
 }
 
+int
+rw_wowned(struct rwlock *rw)
+{
+
+	return (rw_wowner(rw) == curthread);
+}
+
 void
 _rw_wlock(struct rwlock *rw, const char *file, int line)
 {
diff --git a/sys/sys/rwlock.h b/sys/sys/rwlock.h
index 98692a7..13a5436 100644
--- a/sys/sys/rwlock.h
+++ b/sys/sys/rwlock.h
@@ -124,6 +124,7 @@
 void	rw_init(struct rwlock *rw, const char *name);
 void	rw_destroy(struct rwlock *rw);
 void	rw_sysinit(void *arg);
+int	rw_wowned(struct rwlock *rw);
 void	_rw_wlock(struct rwlock *rw, const char *file, int line);
 void	_rw_wunlock(struct rwlock *rw, const char *file, int line);
 void	_rw_rlock(struct rwlock *rw, const char *file, int line);