Re: [linux-usb-devel] [PATCH 02/02] USB: add dynamic id functionality to USB core

From: Greg KH
Date: Thu Nov 17 2005 - 11:59:57 EST


On Thu, Nov 17, 2005 at 10:55:33AM -0500, Alan Stern wrote:
> A few minor comments...
>
> On Wed, 16 Nov 2005, Greg KH wrote:
>
> > +static ssize_t store_new_id(struct device_driver *driver,
> > + const char *buf, size_t count)
> > +{
> > + struct usb_driver *usb_drv = to_usb_driver(driver);
> > + struct usb_dynid *dynid;
> > + u32 idVendor = 0;
> > + u32 idProduct = 0;
> > + int fields = 0;
> > +
> > + fields = sscanf(buf, "%x %x", &idVendor, &idProduct);
> > + if (fields < 0)
> > + return -EINVAL;
>
> Don't you want to test (fields < 2)?

No, it's ok to just specify the vendor, if you want a product of 0 :)

PCI does it this way too.

> > + if (get_driver(&usb_drv->driver)) {
> > + driver_attach(&usb_drv->driver);
> > + put_driver(&usb_drv->driver);
> > + }
>
> Here you don't have to refer to &usb_drv->driver; you can just refer to
> driver.

Good point, changed, thanks.

> > +static int usb_create_newid_file(struct usb_driver *usb_drv)
> > +{
> > + int error = 0;
> > +
> > + if (usb_drv->probe != NULL)
> > + error = sysfs_create_file(&usb_drv->driver.kobj,
> > + &driver_attr_new_id.attr);
> > + return error;
> > +}
>
> This deserves to be an inline function.
>
> > +static void usb_free_dynids(struct usb_driver *usb_drv)
> > +{
> > + struct usb_dynid *dynid, *n;
> > +
> > + spin_lock(&usb_drv->dynids.lock);
> > + list_for_each_entry_safe(dynid, n, &usb_drv->dynids.list, node) {
> > + list_del(&dynid->node);
> > + kfree(dynid);
> > + }
> > + spin_unlock(&usb_drv->dynids.lock);
> > +}
>
> This could be inline as well, although being longer, its overhead is less
> noticeable.

It's just not worth it to inline these, it's not speed critical at all.
I prefer to not inline stuff unless it help out somehow.

thanks for the review,

greg k-h
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