iwlwifi: pcie: don't swallow error codes in iwl_trans_pcie_alloc()

The iwl_trans_pcie_alloc() function doesn't pass up error codes
returned from functions it calls, swallowing them and returning NULL
in all failure cases.  The caller checks if the return value is NULL
and returns -ENOMEM.  This is not correct, because in certain cases
the failure was not due to an OOM situation.

To fix this, modify the iwl_trans_pcie_alloc() function to use
ERR_PTR() to return error codes and clean up the error handling code
a bit.

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

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

@@ -324,8 +324,8 @@ static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	int ret;
 
 	iwl_trans = iwl_trans_pcie_alloc(pdev, ent, cfg);
-	if (iwl_trans == NULL)
-		return -ENOMEM;
+	if (IS_ERR(iwl_trans))
+		return PTR_ERR(iwl_trans);
 
 	pci_set_drvdata(pdev, iwl_trans);
 

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

@@ -1381,9 +1381,10 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
 
 	trans = kzalloc(sizeof(struct iwl_trans) +
 			sizeof(struct iwl_trans_pcie), GFP_KERNEL);
-
-	if (!trans)
-		return NULL;
+	if (!trans) {
+		err = -ENOMEM;
+		goto out;
+	}
 
 	trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 
@@ -1406,10 +1407,9 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
 				       PCIE_LINK_STATE_CLKPM);
 	}
 
-	if (pci_enable_device(pdev)) {
-		err = -ENODEV;
+	err = pci_enable_device(pdev);
+	if (err)
 		goto out_no_pci;
-	}
 
 	pci_set_master(pdev);
 
@@ -1478,17 +1478,20 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
 				  SLAB_HWCACHE_ALIGN,
 				  NULL);
 
-	if (!trans->dev_cmd_pool)
+	if (!trans->dev_cmd_pool) {
+		err = -ENOMEM;
 		goto out_pci_disable_msi;
+	}
 
 	trans_pcie->inta_mask = CSR_INI_SET_MASK;
 
 	if (iwl_pcie_alloc_ict(trans))
 		goto out_free_cmd_pool;
 
-	if (request_threaded_irq(pdev->irq, iwl_pcie_isr_ict,
-				 iwl_pcie_irq_handler,
-				 IRQF_SHARED, DRV_NAME, trans)) {
+	err = request_threaded_irq(pdev->irq, iwl_pcie_isr_ict,
+				   iwl_pcie_irq_handler,
+				   IRQF_SHARED, DRV_NAME, trans);
+	if (err) {
 		IWL_ERR(trans, "Error allocating IRQ %d\n", pdev->irq);
 		goto out_free_ict;
 	}
@@ -1507,5 +1510,6 @@ out_pci_disable_device:
 	pci_disable_device(pdev);
 out_no_pci:
 	kfree(trans);
-	return NULL;
+out:
+	return ERR_PTR(err);
 }