On Wed, Mar 31, 2021 at 09:04:32AM -0700, Dan Williams wrote: > On Wed, Mar 31, 2021 at 6:10 AM Jason Gunthorpe <[email protected]> wrote: > > > > On Tue, Mar 30, 2021 at 04:36:42PM -0700, Dan Williams wrote: > > > +static int cxl_mem_add_memdev(struct cxl_mem *cxlm) > > > +{ > > > + struct cxl_memdev *cxlmd; > > > + struct device *dev; > > > + struct cdev *cdev; > > > + int rc; > > > + > > > + cxlmd = cxl_memdev_alloc(cxlm); > > > + if (IS_ERR(cxlmd)) > > > + return PTR_ERR(cxlmd); > > > + > > > + dev = &cxlmd->dev; > > > + rc = dev_set_name(dev, "mem%d", cxlmd->id); > > > + if (rc) > > > + goto err; > > > > > > + cdev = &cxlmd->cdev; > > > cxl_memdev_activate(cxlmd, cxlm); > > > rc = cdev_device_add(cdev, dev); > > > if (rc) > > > - goto err_add; > > > + goto err; > > > > It might read nicer to have the error unwind here just call > > cxl_memdev_unregister() > > Perhaps, but I don't think cdev_del() and device_del() are prepared to > deal with an object that was not successfully added.
Oh, probably not, yuk yuk yuk. Ideally cdev_device_add should not fail in a way that allows an open, I think that is just an artifact of it being composed of smaller functions.. For instance if we replace the kobj_map with xarray then we can use xa_reserve and xa_store to avoid this condition. This actually looks like a good fit because the dev_t has pretty "lumpy" allocations and this isn't really performance sensitive. A clever person could then make the dev_t self allocating and solve another pain point with this interface. Hum.. Jason
