@@ -231,6 +231,17 @@ static int iwl_pcie_gen2_set_tb(struct iwl_trans *trans,
int idx = iwl_pcie_gen2_get_num_tbs(trans, tfd);
struct iwl_tfh_tb *tb;
+ /*
+ * Only WARN here so we know about the issue, but we mess up our
+ * unmap path because not every place currently checks for errors
+ * returned from this function - it can only return an error if
+ * there's no more space, and so when we know there is enough we
+ * don't always check ...
+ */
+ WARN(crosses_4g_boundary(addr, len),
+ "possible DMA problem with iova:0x%llx, len:%d\n",
+ (unsigned long long)addr, len);
+
if (WARN_ON(idx >= IWL_TFH_NUM_TBS))
return -EINVAL;
tb = &tfd->tbs[idx];