usb: gadget: f_hid: fix error handling in ghid_setup()

PATCH New Dan Carpenter 1 participant 1 message Nov 13, 2014

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Dan Carpenter

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2014-11-13 06:20 UTC #0 lore raw

PATCH 2/2 usb: gadget: f_hid: fix error handling in ghid_setup()

There were a two issues here.

1) We returned PTR_ERR(NULL) which means success if class_create() failed.
2) If alloc_chrdev_region() failed then we should clean up before returning.

Also kernel style is to have "error handling" as opposed to "success handling". In the original code checking for "if (!status) " is confusing and this bad style is what lead to bug #2.

Signed-off-by Dan Carpenter <[email protected]>

drivers/usb/gadget/function/f_hid.c +10 -5

index 220035f..cecdc75 100644
@@ -972,17 +972,22 @@ int ghid_setup(struct usb_gadget *g, int count)
 
 	hidg_class = class_create(THIS_MODULE, "hidg");
 	if (IS_ERR(hidg_class)) {
+		status = PTR_ERR(hidg_class);
 		hidg_class = NULL;
-		return PTR_ERR(hidg_class);
+		return status;
 	}
 
 	status = alloc_chrdev_region(&dev, 0, count, "hidg");
-	if (!status) {
-		major = MAJOR(dev);
-		minors = count;
+	if (status) {
+		class_destroy(hidg_class);
+		hidg_class = NULL;
+		return status;
 	}
 
-	return status;
+	major = MAJOR(dev);
+	minors = count;
+
+	return 0;
 }
 
 void ghid_cleanup(void)