Date: Wed, 27 Apr 2016 10:41:37 -0700
From: Greg KH <gregkh@linuxfoundation.org>
To: "Simon A. F. Lund" <slund@cnexlabs.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, mb@lightnvm.io
Subject: Re: [RFC PATCH] lightnvm: expose configuration through sysfs
Message-ID: <20160427174137.GA10513@kroah.com>
References: <1461777537-8145-1-git-send-email-slund@cnexlabs.com>
 <1461777537-8145-2-git-send-email-slund@cnexlabs.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1461777537-8145-2-git-send-email-slund@cnexlabs.com>
User-Agent: Mutt/1.6.0 (2016-04-01)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1128
Lines: 42

On Wed, Apr 27, 2016 at 10:18:57AM -0700, Simon A. F. Lund wrote:
> --- a/include/linux/lightnvm.h
> +++ b/include/linux/lightnvm.h
> @@ -174,6 +174,7 @@ struct nvm_id_group {
>  	u16	cpar;
>  
>  	struct nvm_id_lp_tbl lptbl;
> +	struct kobject kobj;
>  };
>  
>  struct nvm_addr_format {
> @@ -205,6 +206,7 @@ struct nvm_target {
>  	struct list_head list;
>  	struct nvm_tgt_type *type;
>  	struct gendisk *disk;
> +	struct kobject kobj;
>  };
>  
>  struct nvm_tgt_instance {
> @@ -360,6 +362,8 @@ struct nvm_dev {
>  
>  	struct mutex mlock;
>  	spinlock_t lock;
> +
> +	struct kobject kobj;
>  };
>  
>  static inline struct ppa_addr generic_to_dev_addr(struct nvm_dev *dev,

Never use "raw" kobjects in a driver for a device.  You just guaranteed
that userspace tools will not see these devices or attributes, which
implies you didn't really test this using libudev :(

Please use real devices, attached to the real devices your disks already
have in the tree.

And are you sure you didn't just mess up your reference counting by
now having the lifecycle of these structures be dictated by the kobject?

thanks,

greg k-h