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workqueues: do CPU_UP_CANCELED if CPU_UP_PREPARE fails

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The bug was pointed out by Akinobu Mita <akinobu.mita@gmail.com>, and this
patch is based on his original patch.

workqueue_cpu_callback(CPU_UP_PREPARE) expects that if it returns
NOTIFY_BAD, _cpu_up() will send CPU_UP_CANCELED then.

However, this is not true since

	"cpu hotplug: cpu: deliver CPU_UP_CANCELED only to NOTIFY_OKed callbacks with CPU_UP_PREPARE"
	commit: a0d8cdb652

The callback which has returned NOTIFY_BAD will not receive
CPU_UP_CANCELED.  Change the code to fulfil the CPU_UP_CANCELED logic if
CPU_UP_PREPARE fails.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Reported-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2008-07-25 01:47:54 -07:00 committed by Linus Torvalds
parent 8de6d308ba
commit 8448502cfc
1 changed files with 6 additions and 3 deletions
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9
kernel/workqueue.c
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@ -911,6 +911,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
unsigned int cpu = (unsigned long)hcpu;
struct cpu_workqueue_struct *cwq;
struct workqueue_struct *wq;
int ret = NOTIFY_OK;
action &= ~CPU_TASKS_FROZEN;
@ -918,7 +919,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
case CPU_UP_PREPARE:
cpu_set(cpu, cpu_populated_map);
}
undo:
list_for_each_entry(wq, &workqueues, list) {
cwq = per_cpu_ptr(wq->cpu_wq, cpu);
@ -928,7 +929,9 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
break;
printk(KERN_ERR "workqueue [%s] for %i failed\n",
wq->name, cpu);
return NOTIFY_BAD;
action = CPU_UP_CANCELED;
ret = NOTIFY_BAD;
goto undo;
case CPU_ONLINE:
start_workqueue_thread(cwq, cpu);
@ -948,7 +951,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
cpu_clear(cpu, cpu_populated_map);
}
return NOTIFY_OK;
return ret;
}
void __init init_workqueues(void)