[PATCH v3 09/16] sunrpc: introduce rpc_pipefs_add_destroy_cb()

[Kirill A. Shutemov]

On Fri, Jan 14, 2011 at 03:49:07PM +0200, Kirill A. Shutemov wrote:
> Add facility to do some action on destroying of rpc_pipefs superblock.
> 
> Signed-off-by: Kirill A. Shutemov <kas at openvz.org>
> ---
>  include/linux/sunrpc/rpc_pipe_fs.h |    3 ++
>  net/sunrpc/rpc_pipe.c              |   51 ++++++++++++++++++++++++++++++++++-
>  2 files changed, 52 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/sunrpc/rpc_pipe_fs.h b/include/linux/sunrpc/rpc_pipe_fs.h
> index b09bfa5..f5216f1 100644
> --- a/include/linux/sunrpc/rpc_pipe_fs.h
> +++ b/include/linux/sunrpc/rpc_pipe_fs.h
> @@ -46,6 +46,9 @@ RPC_I(struct inode *inode)
>  
>  extern struct vfsmount *init_rpc_pipefs;
>  
> +extern int rpc_pipefs_add_destroy_cb(struct super_block *sb,
> +		void (*destroy_cb)(void *data), void *data);
> +
>  extern int rpc_queue_upcall(struct inode *, struct rpc_pipe_msg *);
>  
>  struct rpc_clnt;
> diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
> index 484c9a3..39511e3 100644
> --- a/net/sunrpc/rpc_pipe.c
> +++ b/net/sunrpc/rpc_pipe.c
> @@ -939,6 +939,31 @@ static const struct super_operations s_ops = {
>  
>  #define RPCAUTH_GSSMAGIC 0x67596969
>  
> +struct destroy_cb {
> +	struct list_head list;
> +	void (*callback)(void *data);
> +	void *data;
> +};
> +
> +int rpc_pipefs_add_destroy_cb(struct super_block *sb,
> +		void (*destroy_cb)(void *data), void *data)
> +{
> +	struct destroy_cb *dcb;
> +	struct list_head *destroy_cb_list = sb->s_fs_info;
> +
> +	dcb = kmalloc(sizeof(*dcb), GFP_KERNEL);
> +	if (!dcb)
> +		return -ENOMEM;
> +
> +	dcb->callback = destroy_cb;
> +	dcb->data = data;
> +	INIT_LIST_HEAD(&dcb->list);
> +	list_add(&dcb->list, destroy_cb_list);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(rpc_pipefs_add_destroy_cb);
> +
>  /*
>   * We have a single directory with 1 node in it.
>   */
> @@ -1004,8 +1029,16 @@ rpc_fill_super(struct super_block *sb, void *data, int silent)
>  		iput(inode);
>  		return -ENOMEM;
>  	}
> -	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
> +	/* List of destroy callbacks */
> +	sb->s_fs_info = kmalloc(sizeof(struct list_head), GFP_KERNEL);
> +	if (!sb->s_fs_info)
> +		return -ENOMEM;
> +	INIT_LIST_HEAD((struct list_head*) &sb->s_fs_info);

'&' is by mistake here.

> +	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL)) {
> +		kfree(sb->s_fs_info);
>  		return -ENOMEM;
> +	}
> +
>  	return 0;
>  }

-- 
 Kirill A. Shutemov