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[S390] sclp: fix possible deadlock on cpu rescan.

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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>
This commit is contained in:
Heiko Carstens 2008-07-14 09:57:28 +02:00
parent 0c3252d58c
commit b9732ca1cb
1 changed files with 12 additions and 1 deletions
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13
drivers/s390/char/sclp_config.c
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@ -8,6 +8,7 @@
#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>
@ -40,9 +41,19 @@ static void sclp_cpu_capability_notify(struct work_struct *work)
put_online_cpus();
}
static void __ref sclp_cpu_change_notify(struct work_struct *work)
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)