From 1107ba885e46964316c083d441d5dd185b6c9e49 Mon Sep 17 00:00:00 2001
From: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Date: Wed, 7 Jan 2009 18:07:11 -0800
Subject: xen: add xenfs to allow usermode <-> Xen interaction

The xenfs filesystem exports various interfaces to usermode.  Initially
this exports a file to allow usermode to interact with xenbus/xenstore.

Traditionally this appeared in /proc/xen.  Rather than extending procfs,
this patch adds a backward-compat mountpoint on /proc/xen, and provides
a xenfs filesystem which can be mounted there.

Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/xen/xenbus/xenbus_probe.c | 28 ++++++++++++++++++++++------
 drivers/xen/xenbus/xenbus_xs.c    |  1 +
 2 files changed, 23 insertions(+), 6 deletions(-)

(limited to 'drivers/xen/xenbus')

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index b2a0318..773d1cf 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -40,6 +40,7 @@
 #include <linux/ctype.h>
 #include <linux/fcntl.h>
 #include <linux/mm.h>
+#include <linux/proc_fs.h>
 #include <linux/notifier.h>
 #include <linux/kthread.h>
 #include <linux/mutex.h>
@@ -55,7 +56,10 @@
 #include "xenbus_comms.h"
 #include "xenbus_probe.h"
 
+
 int xen_store_evtchn;
+EXPORT_SYMBOL(xen_store_evtchn);
+
 struct xenstore_domain_interface *xen_store_interface;
 static unsigned long xen_store_mfn;
 
@@ -166,6 +170,9 @@ static int read_backend_details(struct xenbus_device *xendev)
 	return read_otherend_details(xendev, "backend-id", "backend");
 }
 
+static struct device_attribute xenbus_dev_attrs[] = {
+	__ATTR_NULL
+};
 
 /* Bus type for frontend drivers. */
 static struct xen_bus_type xenbus_frontend = {
@@ -174,12 +181,13 @@ static struct xen_bus_type xenbus_frontend = {
 	.get_bus_id = frontend_bus_id,
 	.probe = xenbus_probe_frontend,
 	.bus = {
-		.name     = "xen",
-		.match    = xenbus_match,
-		.uevent   = xenbus_uevent,
-		.probe    = xenbus_dev_probe,
-		.remove   = xenbus_dev_remove,
-		.shutdown = xenbus_dev_shutdown,
+		.name      = "xen",
+		.match     = xenbus_match,
+		.uevent    = xenbus_uevent,
+		.probe     = xenbus_dev_probe,
+		.remove    = xenbus_dev_remove,
+		.shutdown  = xenbus_dev_shutdown,
+		.dev_attrs = xenbus_dev_attrs,
 	},
 };
 
@@ -852,6 +860,14 @@ static int __init xenbus_probe_init(void)
 	if (!xen_initial_domain())
 		xenbus_probe(NULL);
 
+#ifdef CONFIG_XEN_COMPAT_XENFS
+	/*
+	 * Create xenfs mountpoint in /proc for compatibility with
+	 * utilities that expect to find "xenbus" under "/proc/xen".
+	 */
+	proc_mkdir("xen", NULL);
+#endif
+
 	return 0;
 
   out_unreg_back:
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 7f2f91c..e325eab 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -184,6 +184,7 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 
 	return ret;
 }
+EXPORT_SYMBOL(xenbus_dev_request_and_reply);
 
 /* Send message to xs, get kmalloc'ed reply.  ERR_PTR() on error. */
 static void *xs_talkv(struct xenbus_transaction t,
-- 
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