Re: [PATCH net-next] mdio_bus: Fix PTR_ERR() usage after initialization to constant

On Tue, Jan 29, 2019 at 11:30:27AM +0800, YueHaibing wrote:

quoted

quoted

 		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
 					       "reset-gpios", 0, GPIOD_OUT_LOW,
 					       "PHY reset");
-	if (PTR_ERR(gpiod) == -ENOENT ||
-	    PTR_ERR(gpiod) == -ENOSYS)
-		gpiod = NULL;
-	else if (IS_ERR(gpiod))
-		return PTR_ERR(gpiod);
+	if (IS_ERR(gpiod)) {
+		ret = PTR_ERR(gpiod);
+		if (ret == -ENOENT || ret == -ENOSYS)
+			gpiod = NULL;
+		else
+			return ret;
+	}

Rule of the thumb: PTR_ERR(p) == -E... is almost always better off
as p == ERR_PTR(-E...)