Messages in this thread | | | Date | Tue, 4 Apr 2006 14:15:05 -0700 | From | Greg KH <> | Subject | Re: patch bus_add_device-losing-an-error-return-from-the-probe-method.patch added to gregkh-2.6 tree |
| |
On Tue, Apr 04, 2006 at 02:00:48PM -0700, Greg KH wrote: > On Tue, Apr 04, 2006 at 04:23:43PM -0400, Dmitry Torokhov wrote: > > On 4/4/06, gregkh@suse.de <gregkh@suse.de> wrote: > > > > > > --- gregkh-2.6.orig/drivers/base/bus.c > > > +++ gregkh-2.6/drivers/base/bus.c > > > @@ -372,14 +372,17 @@ int bus_add_device(struct device * dev) > > > > > > if (bus) { > > > pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id); > > > - device_attach(dev); > > > + error = device_attach(dev); > > > + if (error < 0) > > > + goto exit; > > > > I do not believe that this is correct. The fact that _some_ driver > > failed to attach to a device does not necessarily mean that device > > itself does not exist. While this assuption might work for platform > > devices it won't work for other busses. > > Hm, no, I unwound this mess, and found the following: > > - bus_add_device() calls device_attach() > - device_attach() calls bus_for_each_drv() for every driver on the bus > - bus_for_each_drv() walks all drivers on the bus and calls > __device_attach() for every individual driver > - __device_attach() calls driver_probe_device() for that driver and device > - driver_probe_device() calls down to the probe() function for the > driver, passing it that driver, if match() for the bus matches this > device. > - if that probe() function returns -ENODEV or -ENXIO[1] then the error > is ignored and 0 is returned, causing the loop to continue to try > more drivers > - if the probe() function returns any other error code, it is > propagated up, all the way back to bus_add_device. > - if the probe() function returns 0, the device is bound to the driver, > and it returns 0. Hm, looks like we continue to loop here too, we > could probably stop now that we have bound a driver to the device. > > So, I'm pretty sure that this is safe and should work just fine. To be > sure, let me go reboot my box with this change on it after I finish this > email :)
Yup, things still seem to work properly for me. The patch will show up in the next -mm for others to beat on...
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |