From f7c1a9cd63c03f6f5843c0e918c445303d861d94 Mon Sep 17 00:00:00 2001
From: "kaf24@firebug.cl.cam.ac.uk" <kaf24@firebug.cl.cam.ac.uk>
Date: Wed, 12 Oct 2005 09:33:03 +0100
Subject: [PATCH] This patch implements select() functionality on /dev/vtpm and
 fixes some other problems.

Signed-off-by: Stefan Berger <stefanb@us.ibm.com>
---
 linux-2.6-xen-sparse/drivers/xen/tpmback/tpmback.c   | 10 ++++++++--
 linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c |  9 ++++++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/linux-2.6-xen-sparse/drivers/xen/tpmback/tpmback.c b/linux-2.6-xen-sparse/drivers/xen/tpmback/tpmback.c
index f5c0ccb10a..0a8d70528c 100644
--- a/linux-2.6-xen-sparse/drivers/xen/tpmback/tpmback.c
+++ b/linux-2.6-xen-sparse/drivers/xen/tpmback/tpmback.c
@@ -17,6 +17,7 @@
 #include <linux/types.h>
 #include <linux/list.h>
 #include <linux/miscdevice.h>
+#include <linux/poll.h>
 #include <asm/uaccess.h>
 #include <asm-xen/xenbus.h>
 #include <asm-xen/xen-public/grant_table.h>
@@ -680,9 +681,14 @@ vtpm_op_release(struct inode *inode, struct file *file)
 }
 
 static unsigned int
-vtpm_op_poll(struct file *file, struct poll_table_struct *pst)
+vtpm_op_poll(struct file *file, struct poll_table_struct *pts)
 {
-	return 0;
+	unsigned int flags = POLLOUT | POLLWRNORM;
+	poll_wait(file, &dataex.wait_queue, pts);
+	if (!list_empty(&dataex.pending_pak)) {
+		flags |= POLLIN | POLLRDNORM;
+	}
+	return flags;
 }
 
 static struct file_operations vtpm_ops = {
diff --git a/linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c b/linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c
index 09ffb02002..9276c19354 100644
--- a/linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c
+++ b/linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c
@@ -39,6 +39,7 @@
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/tpmfe.h>
+#include <linux/err.h>
 
 #include <asm/semaphore.h>
 #include <asm/io.h>
@@ -372,7 +373,7 @@ again:
 	info->watch.callback = watch_for_status;
 	err = register_xenbus_watch(&info->watch);
 	if (err) {
-		message = "registering watch on backend";
+		xenbus_dev_error(dev, err, "registering watch on backend");
 		goto destroy_tpmring;
 	}
 
@@ -398,6 +399,8 @@ static int tpmfront_probe(struct xenbus_device *dev,
 	int err;
 	struct tpmfront_info *info;
 	int handle;
+	int len = max(XS_WATCH_PATH, XS_WATCH_TOKEN) + 1;
+	const char *vec[len];
 
 	err = xenbus_scanf(NULL, dev->nodename,
 	                   "handle", "%i", &handle);
@@ -427,6 +430,10 @@ static int tpmfront_probe(struct xenbus_device *dev,
 		return err;
 	}
 
+	vec[XS_WATCH_PATH]  = info->watch.node;
+	vec[XS_WATCH_TOKEN] = NULL;
+	watch_for_status(&info->watch, vec, len);
+
 	return 0;
 }
 
-- 
2.30.2