iw_cxgb4: invalidate the mr when posting a read_w_inv wr

Also, rearrange things a bit to have a common c4iw_invalidate_mr()
function used everywhere that we need to invalidate.

Fixes: 49b53a93a6 ("iw_cxgb4: add fast-path for small REG_MR operations")
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/cxgb4/mem.c

@@ -770,3 +770,15 @@ int c4iw_dereg_mr(struct ib_mr *ib_mr)
 	kfree(mhp);
 	return 0;
 }
+
+void c4iw_invalidate_mr(struct c4iw_dev *rhp, u32 rkey)
+{
+	struct c4iw_mr *mhp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rhp->lock, flags);
+	mhp = get_mhp(rhp, rkey >> 8);
+	if (mhp)
+		mhp->attr.state = 0;
+	spin_unlock_irqrestore(&rhp->lock, flags);
+}