IB/srpt: Cache global L_Key

This patch is a micro-optimization for the hot path.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/srpt/ib_srpt.h

@@ -343,7 +343,7 @@ struct srpt_port {
  * struct srpt_device - Information associated by SRPT with a single HCA.
  * @device:        Backpointer to the struct ib_device managed by the IB core.
  * @pd:            IB protection domain.
- * @mr:            L_Key (local key) with write access to all local memory.
+ * @lkey:          L_Key (local key) with write access to all local memory.
  * @srq:           Per-HCA SRQ (shared receive queue).
  * @cm_id:         Connection identifier.
  * @srq_size:      SRQ size.
@@ -358,6 +358,7 @@ struct srpt_port {
 struct srpt_device {
 	struct ib_device	*device;
 	struct ib_pd		*pd;
+	u32			lkey;
 	struct ib_srq		*srq;
 	struct ib_cm_id		*cm_id;
 	int			srq_size;