From: cl349@firebug.cl.cam.ac.uk <cl349@firebug.cl.cam.ac.uk>
Date: Tue, 13 Sep 2005 21:29:28 +0000 (+0000)
Subject: Perform xenbus operations in shutdown_handler in a transaction.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~16806^2~25
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=49917db5e9842a569854d34cabf8436285fdde69;p=xen.git

Perform xenbus operations in shutdown_handler in a transaction.
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
---

diff --git a/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c b/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c
index b6608cef49..12c7610e90 100644
--- a/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c
+++ b/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c
@@ -320,20 +320,28 @@ static void __shutdown_handler(void *unused)
 static void shutdown_handler(struct xenbus_watch *watch, const char *node)
 {
     static DECLARE_WORK(shutdown_work, __shutdown_handler, NULL);
-
     char *str;
+    int err;
 
+ again:
+    err = xenbus_transaction_start("control");
+    if (err)
+	return;
     str = (char *)xenbus_read("control", "shutdown", NULL);
-    /* Ignore read errors. */
-    if (IS_ERR(str))
-        return;
-    if (strlen(str) == 0) {
-        kfree(str);
-        return;
+    /* Ignore read errors and empty reads. */
+    if (XENBUS_IS_ERR_READ(str)) {
+	xenbus_transaction_end(1);
+	return;
     }
 
     xenbus_write("control", "shutdown", "", O_CREAT);
 
+    err = xenbus_transaction_end(0);
+    if (err == -ETIMEDOUT) {
+	kfree(str);
+	goto again;
+    }
+
     if (strcmp(str, "poweroff") == 0)
         shutting_down = SHUTDOWN_POWEROFF;
     else if (strcmp(str, "reboot") == 0)