re #13613 rb4516 Tunables needs volatile keyword

*** 20,29 ****
--- 20,32 ----
   */
  /*
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
+ /*
+  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+  */
  
  #include <sys/systm.h>
  #include <sys/types.h>
  #include <sys/vnode.h>
  #include <sys/errno.h>
*** 37,48 ****
  #include <sys/fs/ufs_inode.h>
  #include <sys/fs/ufs_filio.h>
  #include <sys/fs/ufs_log.h>
  #include <sys/fs/ufs_bio.h>
  #include <sys/atomic.h>
  
- extern int              maxphys;
  extern uint_t           bypass_snapshot_throttle_key;
  
  extern struct kmem_cache        *lufs_sv;
  extern struct kmem_cache        *lufs_bp;
  
--- 40,51 ----
  #include <sys/fs/ufs_inode.h>
  #include <sys/fs/ufs_filio.h>
  #include <sys/fs/ufs_log.h>
  #include <sys/fs/ufs_bio.h>
  #include <sys/atomic.h>
+ #include <sys/sunddi.h>
  
  extern uint_t           bypass_snapshot_throttle_key;
  
  extern struct kmem_cache        *lufs_sv;
  extern struct kmem_cache        *lufs_bp;