IB/qib: Fix local access validation for user MRs

Commit 8aac4cc3a9 ("IB/qib: RCU locking for MR validation") introduced
a bug that broke user post sends.  The proper validation of the MR
was lost in the patch.

This patch corrects that validation.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/qib/qib_keys.c

@@ -186,8 +186,9 @@ int qib_lkey_ok(struct qib_lkey_table *rkt, struct qib_pd *pd,
 		goto bail;
 
 	off = sge->addr - mr->user_base;
-	if (unlikely(sge->addr < mr->iova || off + sge->length > mr->length ||
-		     (mr->access_flags & acc) == 0))
+	if (unlikely(sge->addr < mr->user_base ||
+		     off + sge->length > mr->length ||
+		     (mr->access_flags & acc) != acc))
 		goto bail;
 	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
 		goto bail;