[Xen-changelog] [linux-2.6.18-xen] evtchn: adjust CPU notifier registration

[Xen patchbot-linux-2.6.18-xen <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1378807571 -7200
# Node ID b94250095e987b539baa08c82d0f2861fa3c85fe
# Parent  f2d05cf62925cc1146c8ac37964b8f8bd82a69c3
evtchn: adjust CPU notifier registration

While mostly benign in 2.6.18 (apart from avoiding registration of a
notifier that would never do anything useful under !HOTPLUG_CPU), the
distinction is quite relevant when backporting the driver to 2.6.16:
register_cpu_notifier() is available to modules there even when
!HOTPLUG_CPU, and thus no such notifier block must live in
.cpuinit.data (or else modules calling register_cpu_notifier() will
result in hitting an unmapped page when traversing the linked list of
notifiers).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---


diff -r f2d05cf62925 -r b94250095e98 drivers/xen/evtchn/evtchn.c
--- a/drivers/xen/evtchn/evtchn.c       Thu Jun 20 14:38:29 2013 +0200
+++ b/drivers/xen/evtchn/evtchn.c       Tue Sep 10 12:06:11 2013 +0200
@@ -492,7 +492,8 @@ static struct miscdevice evtchn_miscdev 
        .fops         = &evtchn_fops,
 };
 
-static int __cpuinit evtchn_cpu_notify(struct notifier_block *nfb,
+#ifdef CONFIG_HOTPLUG_CPU
+static int evtchn_cpu_notify(struct notifier_block *nfb,
                        unsigned long action, void *hcpu)
 {
        int hotcpu = (unsigned long)hcpu;
@@ -522,9 +523,10 @@ static int __cpuinit evtchn_cpu_notify(s
        return NOTIFY_OK;
 }
 
-static struct notifier_block __cpuinitdata evtchn_cpu_nfb = {
+static struct notifier_block evtchn_cpu_nfb = {
        .notifier_call = evtchn_cpu_notify
 };
+#endif
 
 static int __init evtchn_init(void)
 {
@@ -543,7 +545,7 @@ static int __init evtchn_init(void)
                return err;
        }
 
-       register_cpu_notifier(&evtchn_cpu_nfb);
+       register_hotcpu_notifier(&evtchn_cpu_nfb);
 
        printk("Event-channel device installed.\n");
 
@@ -553,7 +555,7 @@ static int __init evtchn_init(void)
 static void __exit evtchn_cleanup(void)
 {
        misc_deregister(&evtchn_miscdev);
-       unregister_cpu_notifier(&evtchn_cpu_nfb);
+       unregister_hotcpu_notifier(&evtchn_cpu_nfb);
 }
 
 module_init(evtchn_init);

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog