On Fri, Jul 27, 2012 at 03:08:21PM -0400, Matthew Wilcox wrote: > On Fri, Jul 27, 2012 at 11:25:46AM -0700, Greg KH wrote: > > On Fri, Jul 27, 2012 at 02:12:12PM -0400, Matthew Wilcox wrote: > > > I don't see a problem here, but I'm no expert at sysfs / character > > > devices. > > > Alan, Greg, anyone else see any problems with how this character device is > > > created / destroyed? > > > > Yes, see below: > > Thanks! > > > > > + device_create(nvme_char_cl, NULL, MKDEV(nvme_char_major, > > > > dev->instance), > > > > + NULL, "nvme%d", > > > > dev->instance); > > > > You just created a device at the "root" of sysfs, which is wrong, > > especially when you do have a parent device here. Please use it. > > OK, that makes sense; this device should be the child of the pci_dev that > it belongs to. > > > Also, why are you creating your own class? Can't this just be a misc > > device? And if you want to create your own class, please don't, use a > > bus, as that is what is really happening here, right? We are trying to > > move away from using 'struct class' wherever possible (one of these days > > we'll just remove it...) > > What we're trying to achieve here is to create one character device > per NVMe controller that gets plugged in. Each NVMe controller is-a > PCI function. The reason we're trying to do this is so that we can send > commands to the NVMe controller, even when there is no storage present > (eg a drive is shipped from the factory with no configured storage). > > So we have no particular desire to create a new struct class, or struct > bus. If we can create a misc device per PCIe function that's bound to our > driver, that's great! Can you recommend a driver that does this already?
I don't think there is one, but it shouldn't be that hard to just create a 'struct misdevice' for each one of the devices you want to create, would it? But, as you really are a "specific type", a bus_type might be overkill, so the original use of device_create() should be fine. Just be sure to fix the parent pointer issue, and you should be fine, right? greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
