reset: hisilicon: fix potential NULL pointer dereference

There is a potential execution path in which function platform_get_resource() returns NULL. If this happens, we will end up having a NULL pointer dereference.

Fix this by replacing devm_ioremap with devm_ioremap_resource, which has the NULL check and the memory region request.

This code was detected with the help of Coccinelle.

---
Changes in v2:
- Use devm_ioremap_resource. Thanks to Stephen Boyd for pointing it out.

 drivers/clk/hisilicon/reset.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

index 2a5015c..43e82fa 100644
@@ -109,9 +109,8 @@ struct hisi_reset_controller *hisi_reset_init(struct platform_device *pdev)
 		return NULL;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	rstc->membase = devm_ioremap(&pdev->dev,
-				res->start, resource_size(res));
-	if (!rstc->membase)
+	rstc->membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rstc->membase))
 		return NULL;
 
 	spin_lock_init(&rstc->lock);

2.7.4

Quoting Gustavo A. R. Silva (2018-07-25 17:47:19)

et_init")

Nobody has reviewed, so I guess applied to clk-next unless someone complains.

Thanks, Stephen.

--
Gustavo