iwlwifi: return -ENOMEM instead of NULL when OOM in iwl_drv_start()

The callers of iwl_drv_start() are probe functions.  If a probe
function returns 0, it means it succeeded.  So if NULL was returned by
iwl_drv_start(), it would be considered as a success.

Fix this by returning -ENOMEM if the driver struct allocation fails in
iwl_drv_start().

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/iwl-drv.c

@@ -1032,8 +1032,10 @@ struct iwl_drv *iwl_drv_start(struct iwl_trans *trans,
 	int ret;
 
 	drv = kzalloc(sizeof(*drv), GFP_KERNEL);
-	if (!drv)
-		return NULL;
+	if (!drv) {
+		ret = -ENOMEM;
+		goto err;
+	}
 
 	drv->trans = trans;
 	drv->dev = trans->dev;
@@ -1078,7 +1080,7 @@ err_free_dbgfs:
 err_free_drv:
 #endif
 	kfree(drv);
-
+err:
 	return ERR_PTR(ret);
 }
 

drivers/net/wireless/iwlwifi/pcie/drv.c

@@ -332,7 +332,7 @@ static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	trans_pcie = IWL_TRANS_GET_PCIE_TRANS(iwl_trans);
 	trans_pcie->drv = iwl_drv_start(iwl_trans, cfg);
 
-	if (IS_ERR_OR_NULL(trans_pcie->drv)) {
+	if (IS_ERR(trans_pcie->drv)) {
 		ret = PTR_ERR(trans_pcie->drv);
 		goto out_free_trans;
 	}