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> - struct device *dev = &cxlmd->dev; > + cxlmd->cxlm = cxlm; > + down_write(&cxl_memdev_rwsem); > + up_write(&cxl_memdev_rwsem); > +} No reason not to put the assignment inside the lock. Though using the lock at all is overkill as the pointer hasn't left the local stack frame at this point. > err_add: > - ida_free(&cxl_memdev_ida, cxlmd->id); > -err_id: > /* > - * Theoretically userspace could have already entered the fops, > - * so flush ops_active. > + * The cdev was briefly live, shutdown any ioctl operations that > + * saw that state. > */ Wow it is really subtle that cdev_device_add has this tiny hole where it can fail but have already allowed open() :< Other than the lock it looks OK Reviewed-by: Jason Gunthorpe Jason