IB/rdmavt: Add mechanism to invalidate MR keys

In order to support extended memory management, add the mechanism to
invalidate MR keys. This includes a flag "lkey_invalid" in the MR data
structure that is to be checked when validating access to the MR via
the associated key, and two utility functions to perform fast memory
registration and memory key invalidate operations.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

include/rdma/rdmavt_mr.h

@@ -81,6 +81,7 @@ struct rvt_mregion {
 	u32 mapsz;              /* size of the map array */
 	u8  page_shift;         /* 0 - non unform/non powerof2 sizes */
 	u8  lkey_published;     /* in global table */
+	atomic_t lkey_invalid;	/* true if current lkey is invalid */
 	struct completion comp; /* complete when refcount goes to zero */
 	atomic_t refcount;
 	struct rvt_segarray *map[0];    /* the segments */