[PATCH retry] drivers/usb/class/usblp.c: adjust error handling code

From: Julia Lawall
Date: Wed Jul 16 2008 - 12:01:00 EST


From: Julia Lawall <julia@xxxxxxx>

In this code, it is possible to tell statically whether usblp will be NULL
in the error handling code.

Oliver Neukum suggested to make a goto to the final return rather than
return directly.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
identifier f,err,l,l1;
type T;
expression x,E;
statement S;
@@

x = NULL
... when != goto l1;
* x = f(...)
... when != x
err = E;
goto l;
...
* if (x != NULL)
S
return err;
// </smpl>

Signed-off-by: Julia Lawall <julia@xxxxxxx>

---
diff -u -p a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -1076,15 +1076,16 @@ static int usblp_probe(struct usb_interf
const struct usb_device_id *id)
{
struct usb_device *dev = interface_to_usbdev (intf);
- struct usblp *usblp = NULL;
+ struct usblp *usblp;
int protocol;
int retval;

/* Malloc and start initializing usblp structure so we can use it
* directly. */
- if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
+ usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL);
+ if (!usblp) {
retval = -ENOMEM;
- goto abort;
+ goto abort_ret;
}
usblp->dev = dev;
mutex_init(&usblp->wmut);
@@ -1179,12 +1180,11 @@ abort_intfdata:
usb_set_intfdata (intf, NULL);
device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
abort:
- if (usblp) {
- kfree(usblp->readbuf);
- kfree(usblp->statusbuf);
- kfree(usblp->device_id_string);
- kfree(usblp);
- }
+ kfree(usblp->readbuf);
+ kfree(usblp->statusbuf);
+ kfree(usblp->device_id_string);
+ kfree(usblp);
+abort_ret:
return retval;
}

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