b9732ca1cb
smp_rescan_cpus() calls get_online_cpus() from a multithreaded workqueue context. This may deadlock. This is the same bug as in arch/s390/kernel/topology.c. This patch can be reverted as soon as Oleg's patch gets merged. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
101 lines
2.2 KiB
C
101 lines
2.2 KiB
C
/*
|
|
* drivers/s390/char/sclp_config.c
|
|
*
|
|
* Copyright IBM Corp. 2007
|
|
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/kthread.h>
|
|
#include <linux/sysdev.h>
|
|
#include <linux/workqueue.h>
|
|
#include <asm/smp.h>
|
|
#include "sclp.h"
|
|
|
|
#define TAG "sclp_config: "
|
|
|
|
struct conf_mgm_data {
|
|
u8 reserved;
|
|
u8 ev_qualifier;
|
|
} __attribute__((packed));
|
|
|
|
#define EV_QUAL_CPU_CHANGE 1
|
|
#define EV_QUAL_CAP_CHANGE 3
|
|
|
|
static struct work_struct sclp_cpu_capability_work;
|
|
static struct work_struct sclp_cpu_change_work;
|
|
|
|
static void sclp_cpu_capability_notify(struct work_struct *work)
|
|
{
|
|
int cpu;
|
|
struct sys_device *sysdev;
|
|
|
|
printk(KERN_WARNING TAG "cpu capability changed.\n");
|
|
get_online_cpus();
|
|
for_each_online_cpu(cpu) {
|
|
sysdev = get_cpu_sysdev(cpu);
|
|
kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
|
|
}
|
|
put_online_cpus();
|
|
}
|
|
|
|
static int sclp_cpu_kthread(void *data)
|
|
{
|
|
smp_rescan_cpus();
|
|
return 0;
|
|
}
|
|
|
|
static void __ref sclp_cpu_change_notify(struct work_struct *work)
|
|
{
|
|
/* Can't call smp_rescan_cpus() from workqueue context since it may
|
|
* deadlock in case of cpu hotplug. So we have to create a kernel
|
|
* thread in order to call it.
|
|
*/
|
|
kthread_run(sclp_cpu_kthread, NULL, "cpu_rescan");
|
|
}
|
|
|
|
static void sclp_conf_receiver_fn(struct evbuf_header *evbuf)
|
|
{
|
|
struct conf_mgm_data *cdata;
|
|
|
|
cdata = (struct conf_mgm_data *)(evbuf + 1);
|
|
switch (cdata->ev_qualifier) {
|
|
case EV_QUAL_CPU_CHANGE:
|
|
schedule_work(&sclp_cpu_change_work);
|
|
break;
|
|
case EV_QUAL_CAP_CHANGE:
|
|
schedule_work(&sclp_cpu_capability_work);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static struct sclp_register sclp_conf_register =
|
|
{
|
|
.receive_mask = EVTYP_CONFMGMDATA_MASK,
|
|
.receiver_fn = sclp_conf_receiver_fn,
|
|
};
|
|
|
|
static int __init sclp_conf_init(void)
|
|
{
|
|
int rc;
|
|
|
|
INIT_WORK(&sclp_cpu_capability_work, sclp_cpu_capability_notify);
|
|
INIT_WORK(&sclp_cpu_change_work, sclp_cpu_change_notify);
|
|
|
|
rc = sclp_register(&sclp_conf_register);
|
|
if (rc) {
|
|
printk(KERN_ERR TAG "failed to register (%d).\n", rc);
|
|
return rc;
|
|
}
|
|
|
|
if (!(sclp_conf_register.sclp_send_mask & EVTYP_CONFMGMDATA_MASK)) {
|
|
printk(KERN_WARNING TAG "no configuration management.\n");
|
|
sclp_unregister(&sclp_conf_register);
|
|
rc = -ENOSYS;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
__initcall(sclp_conf_init);
|