cpumask: Use modern cpumask style in Xen
[linux-2.6.git] / drivers / xen / cpu_hotplug.c
1 #include <linux/notifier.h>
2
3 #include <xen/xenbus.h>
4
5 #include <asm/xen/hypervisor.h>
6 #include <asm/cpu.h>
7
8 static void enable_hotplug_cpu(int cpu)
9 {
10         if (!cpu_present(cpu))
11                 arch_register_cpu(cpu);
12
13         set_cpu_present(cpu, true);
14 }
15
16 static void disable_hotplug_cpu(int cpu)
17 {
18         if (cpu_present(cpu))
19                 arch_unregister_cpu(cpu);
20
21         set_cpu_present(cpu, false);
22 }
23
24 static int vcpu_online(unsigned int cpu)
25 {
26         int err;
27         char dir[32], state[32];
28
29         sprintf(dir, "cpu/%u", cpu);
30         err = xenbus_scanf(XBT_NIL, dir, "availability", "%s", state);
31         if (err != 1) {
32                 printk(KERN_ERR "XENBUS: Unable to read cpu state\n");
33                 return err;
34         }
35
36         if (strcmp(state, "online") == 0)
37                 return 1;
38         else if (strcmp(state, "offline") == 0)
39                 return 0;
40
41         printk(KERN_ERR "XENBUS: unknown state(%s) on CPU%d\n", state, cpu);
42         return -EINVAL;
43 }
44 static void vcpu_hotplug(unsigned int cpu)
45 {
46         if (!cpu_possible(cpu))
47                 return;
48
49         switch (vcpu_online(cpu)) {
50         case 1:
51                 enable_hotplug_cpu(cpu);
52                 break;
53         case 0:
54                 (void)cpu_down(cpu);
55                 disable_hotplug_cpu(cpu);
56                 break;
57         default:
58                 break;
59         }
60 }
61
62 static void handle_vcpu_hotplug_event(struct xenbus_watch *watch,
63                                         const char **vec, unsigned int len)
64 {
65         unsigned int cpu;
66         char *cpustr;
67         const char *node = vec[XS_WATCH_PATH];
68
69         cpustr = strstr(node, "cpu/");
70         if (cpustr != NULL) {
71                 sscanf(cpustr, "cpu/%u", &cpu);
72                 vcpu_hotplug(cpu);
73         }
74 }
75
76 static int setup_cpu_watcher(struct notifier_block *notifier,
77                               unsigned long event, void *data)
78 {
79         int cpu;
80         static struct xenbus_watch cpu_watch = {
81                 .node = "cpu",
82                 .callback = handle_vcpu_hotplug_event};
83
84         (void)register_xenbus_watch(&cpu_watch);
85
86         for_each_possible_cpu(cpu) {
87                 if (vcpu_online(cpu) == 0) {
88                         (void)cpu_down(cpu);
89                         set_cpu_present(cpu, false);
90                 }
91         }
92
93         return NOTIFY_DONE;
94 }
95
96 static int __init setup_vcpu_hotplug_event(void)
97 {
98         static struct notifier_block xsn_cpu = {
99                 .notifier_call = setup_cpu_watcher };
100
101         if (!xen_pv_domain())
102                 return -ENODEV;
103
104         register_xenstore_notifier(&xsn_cpu);
105
106         return 0;
107 }
108
109 arch_initcall(setup_vcpu_hotplug_event);
110