Revert "Remove misguided HAVE_MUTEX_OWNER check"

This reverts commit d89616fda8 which
introduced some build failures which need to be resolved before
this can be merged.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #633

include/sys/mutex.h

@@ -40,8 +40,10 @@ typedef enum {
 typedef struct {
 	struct mutex		m_mutex;
 	spinlock_t		m_lock;	/* used for serializing mutex_exit */
+#ifndef HAVE_MUTEX_OWNER
 	/* only when kernel doesn't have owner */
 	kthread_t		*m_owner;
+#endif
 #ifdef CONFIG_LOCKDEP
 	kmutex_type_t		m_type;
 #endif /* CONFIG_LOCKDEP */
@@ -56,16 +58,24 @@ spl_mutex_set_owner(kmutex_t *mp)
 	 * kernel will handle its owner, so we don't need to do anything if it
 	 * is defined.
 	 */
+#ifndef HAVE_MUTEX_OWNER
 	mp->m_owner = current;
+#endif
 }
 
 static inline void
 spl_mutex_clear_owner(kmutex_t *mp)
 {
+#ifndef HAVE_MUTEX_OWNER
 	mp->m_owner = NULL;
+#endif
 }
 
+#ifdef HAVE_MUTEX_OWNER
 #define	mutex_owner(mp)		(ACCESS_ONCE(MUTEX(mp)->owner))
+#else
+#define	mutex_owner(mp)		(ACCESS_ONCE((mp)->m_owner))
+#endif
 #define	mutex_owned(mp)		(mutex_owner(mp) == current)
 #define	MUTEX_HELD(mp)		mutex_owned(mp)
 #define	MUTEX_NOT_HELD(mp)	(!MUTEX_HELD(mp))