linux/drivers/xen/cpu_hotplug.c
Juergen Gross 5584ea250a xen: modify xenstore watch event interface
Today a Xenstore watch event is delivered via a callback function
declared as:

void (*callback)(struct xenbus_watch *,
                 const char **vec, unsigned int len);

As all watch events only ever come with two parameters (path and token)
changing the prototype to:

void (*callback)(struct xenbus_watch *,
                 const char *path, const char *token);

is the natural thing to do.

Apply this change and adapt all users.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com
Cc: wei.liu2@citrix.com
Cc: paul.durrant@citrix.com
Cc: netdev@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-02-09 11:26:49 -05:00

122 lines
2.2 KiB
C

#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
#include <linux/notifier.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
#include <asm/xen/hypervisor.h>
#include <asm/cpu.h>
static void enable_hotplug_cpu(int cpu)
{
if (!cpu_present(cpu))
xen_arch_register_cpu(cpu);
set_cpu_present(cpu, true);
}
static void disable_hotplug_cpu(int cpu)
{
if (cpu_online(cpu)) {
lock_device_hotplug();
device_offline(get_cpu_device(cpu));
unlock_device_hotplug();
}
if (cpu_present(cpu))
xen_arch_unregister_cpu(cpu);
set_cpu_present(cpu, false);
}
static int vcpu_online(unsigned int cpu)
{
int err;
char dir[16], state[16];
sprintf(dir, "cpu/%u", cpu);
err = xenbus_scanf(XBT_NIL, dir, "availability", "%15s", state);
if (err != 1) {
if (!xen_initial_domain())
pr_err("Unable to read cpu state\n");
return err;
}
if (strcmp(state, "online") == 0)
return 1;
else if (strcmp(state, "offline") == 0)
return 0;
pr_err("unknown state(%s) on CPU%d\n", state, cpu);
return -EINVAL;
}
static void vcpu_hotplug(unsigned int cpu)
{
if (!cpu_possible(cpu))
return;
switch (vcpu_online(cpu)) {
case 1:
enable_hotplug_cpu(cpu);
break;
case 0:
disable_hotplug_cpu(cpu);
break;
default:
break;
}
}
static void handle_vcpu_hotplug_event(struct xenbus_watch *watch,
const char *path, const char *token)
{
unsigned int cpu;
char *cpustr;
cpustr = strstr(path, "cpu/");
if (cpustr != NULL) {
sscanf(cpustr, "cpu/%u", &cpu);
vcpu_hotplug(cpu);
}
}
static int setup_cpu_watcher(struct notifier_block *notifier,
unsigned long event, void *data)
{
int cpu;
static struct xenbus_watch cpu_watch = {
.node = "cpu",
.callback = handle_vcpu_hotplug_event};
(void)register_xenbus_watch(&cpu_watch);
for_each_possible_cpu(cpu) {
if (vcpu_online(cpu) == 0) {
(void)cpu_down(cpu);
set_cpu_present(cpu, false);
}
}
return NOTIFY_DONE;
}
static int __init setup_vcpu_hotplug_event(void)
{
static struct notifier_block xsn_cpu = {
.notifier_call = setup_cpu_watcher };
#ifdef CONFIG_X86
if (!xen_pv_domain() && !xen_pvh_domain())
#else
if (!xen_domain())
#endif
return -ENODEV;
register_xenstore_notifier(&xsn_cpu);
return 0;
}
arch_initcall(setup_vcpu_hotplug_event);