[S390] sclp: fix possible deadlock on cpu rescan.
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>
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@ -8,6 +8,7 @@
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#include <linux/init.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/errno.h>
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#include <linux/cpu.h>
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#include <linux/cpu.h>
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#include <linux/kthread.h>
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#include <linux/sysdev.h>
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#include <linux/sysdev.h>
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#include <linux/workqueue.h>
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#include <linux/workqueue.h>
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#include <asm/smp.h>
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#include <asm/smp.h>
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@ -40,9 +41,19 @@ static void sclp_cpu_capability_notify(struct work_struct *work)
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put_online_cpus();
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put_online_cpus();
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}
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}
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static void __ref sclp_cpu_change_notify(struct work_struct *work)
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static int sclp_cpu_kthread(void *data)
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{
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{
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smp_rescan_cpus();
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smp_rescan_cpus();
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return 0;
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}
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static void __ref sclp_cpu_change_notify(struct work_struct *work)
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{
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/* Can't call smp_rescan_cpus() from workqueue context since it may
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* deadlock in case of cpu hotplug. So we have to create a kernel
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* thread in order to call it.
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*/
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kthread_run(sclp_cpu_kthread, NULL, "cpu_rescan");
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}
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}
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static void sclp_conf_receiver_fn(struct evbuf_header *evbuf)
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static void sclp_conf_receiver_fn(struct evbuf_header *evbuf)
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