Re: [Xen-devel] [PATCH 2/4] xen: Add xenbus device driver

[Ian Campbell <Ian.Campbell@citrix.com>]

On Wed, 2011-12-07 at 21:13 +0000, Bastian Blank wrote:
> Access to xenbus is currently handled via xenfs. This adds a device
> driver for xenbus and makes xenfs use this code.
> 
> Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

> ---
>  drivers/xen/xenbus/Makefile                        |    1 +
>  drivers/xen/xenbus/xenbus_comms.h                  |    4 ++
>  .../xenbus.c => xenbus/xenbus_dev_frontend.c}      |   37 ++++++++++++++++++--
>  drivers/xen/xenfs/Makefile                         |    2 +-
>  drivers/xen/xenfs/super.c                          |    3 +-
>  drivers/xen/xenfs/xenfs.h                          |    1 -
>  6 files changed, 42 insertions(+), 6 deletions(-)
>  rename drivers/xen/{xenfs/xenbus.c => xenbus/xenbus_dev_frontend.c} (95%)
> 
> diff --git a/drivers/xen/xenbus/Makefile b/drivers/xen/xenbus/Makefile
> index 8dca685..a2ea363 100644
> --- a/drivers/xen/xenbus/Makefile
> +++ b/drivers/xen/xenbus/Makefile
> @@ -1,4 +1,5 @@
>  obj-y	+= xenbus.o
> +obj-y	+= xenbus_dev_frontend.o
>  
>  xenbus-objs =
>  xenbus-objs += xenbus_client.o
> diff --git a/drivers/xen/xenbus/xenbus_comms.h b/drivers/xen/xenbus/xenbus_comms.h
> index c21db75..6e42800 100644
> --- a/drivers/xen/xenbus/xenbus_comms.h
> +++ b/drivers/xen/xenbus/xenbus_comms.h
> @@ -31,6 +31,8 @@
>  #ifndef _XENBUS_COMMS_H
>  #define _XENBUS_COMMS_H
>  
> +#include <linux/fs.h>
> +
>  int xs_init(void);
>  int xb_init_comms(void);
>  
> @@ -43,4 +45,6 @@ int xs_input_avail(void);
>  extern struct xenstore_domain_interface *xen_store_interface;
>  extern int xen_store_evtchn;
>  
> +extern const struct file_operations xen_xenbus_fops;
> +
>  #endif /* _XENBUS_COMMS_H */
> diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
> similarity index 95%
> rename from drivers/xen/xenfs/xenbus.c
> rename to drivers/xen/xenbus/xenbus_dev_frontend.c
> index bbd000f..fb30cff 100644
> --- a/drivers/xen/xenfs/xenbus.c
> +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
> @@ -52,13 +52,16 @@
>  #include <linux/namei.h>
>  #include <linux/string.h>
>  #include <linux/slab.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
>  
> -#include "xenfs.h"
> -#include "../xenbus/xenbus_comms.h"
> +#include "xenbus_comms.h"
>  
>  #include <xen/xenbus.h>
>  #include <asm/xen/hypervisor.h>
>  
> +MODULE_LICENSE("GPL");
> +
>  /*
>   * An element of a list of outstanding transactions, for which we're
>   * still waiting a reply.
> @@ -583,7 +586,7 @@ static unsigned int xenbus_file_poll(struct file *file, poll_table *wait)
>  	return 0;
>  }
>  
> -const struct file_operations xenbus_file_ops = {
> +const struct file_operations xen_xenbus_fops = {
>  	.read = xenbus_file_read,
>  	.write = xenbus_file_write,
>  	.open = xenbus_file_open,
> @@ -591,3 +594,31 @@ const struct file_operations xenbus_file_ops = {
>  	.poll = xenbus_file_poll,
>  	.llseek = no_llseek,
>  };
> +EXPORT_SYMBOL_GPL(xen_xenbus_fops);
> +
> +static struct miscdevice xenbus_dev = {
> +	.minor = MISC_DYNAMIC_MINOR,
> +	.name = "xen/xenbus",
> +	.fops = &xen_xenbus_fops,
> +};
> +
> +static int __init xenbus_init(void)
> +{
> +	int err;
> +
> +	if (!xen_domain())
> +		return -ENODEV;
> +
> +	err = misc_register(&xenbus_dev);
> +	if (err)
> +		printk(KERN_ERR "Could not register xenbus device\n");
> +	return err;
> +}
> +
> +static void __exit xenbus_exit(void)
> +{
> +	misc_deregister(&xenbus_dev);
> +}
> +
> +module_init(xenbus_init);
> +module_exit(xenbus_exit);
> diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile
> index 5d45ff1..b019865 100644
> --- a/drivers/xen/xenfs/Makefile
> +++ b/drivers/xen/xenfs/Makefile
> @@ -1,4 +1,4 @@
>  obj-$(CONFIG_XENFS) += xenfs.o
>  
> -xenfs-y			  = super.o xenbus.o
> +xenfs-y			  = super.o
>  xenfs-$(CONFIG_XEN_DOM0) += xenstored.o
> diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
> index a55fbf9..a84b53c 100644
> --- a/drivers/xen/xenfs/super.c
> +++ b/drivers/xen/xenfs/super.c
> @@ -17,6 +17,7 @@
>  
>  #include "xenfs.h"
>  #include "../privcmd.h"
> +#include "../xenbus/xenbus_comms.h"
>  
>  #include <asm/xen/hypervisor.h>
>  
> @@ -83,7 +84,7 @@ static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
>  {
>  	static struct tree_descr xenfs_files[] = {
>  		[1] = {},
> -		{ "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR },
> +		{ "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
>  		{ "capabilities", &capabilities_file_ops, S_IRUGO },
>  		{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
>  		{""},
> diff --git a/drivers/xen/xenfs/xenfs.h b/drivers/xen/xenfs/xenfs.h
> index 5056306..6b80c77 100644
> --- a/drivers/xen/xenfs/xenfs.h
> +++ b/drivers/xen/xenfs/xenfs.h
> @@ -1,7 +1,6 @@
>  #ifndef _XENFS_XENBUS_H
>  #define _XENFS_XENBUS_H
>  
> -extern const struct file_operations xenbus_file_ops;
>  extern const struct file_operations xsd_kva_file_ops;
>  extern const struct file_operations xsd_port_file_ops;
>