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cpu-hotplug: return better errno on cpu hotplug failure

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Currently, onlining or offlining a CPU failure by one of the cpu notifiers
error always cause -EINVAL error.  (i.e.  writing 0 or 1 to
/sys/devices/system/cpu/cpuX/online gets EINVAL)

To get better error reporting rather than always getting -EINVAL, This
changes cpu_notify() to return -errno value with notifier_to_errno() and
fix the callers.  Now that cpu notifiers can return encapsulate errno
value.

Currently, all cpu hotplug notifiers return NOTIFY_OK, NOTIFY_BAD, or
NOTIFY_DONE.  So cpu_notify() can returns 0 or -EPERM with this change for
now.

(notifier_to_errno(NOTIFY_OK) == 0, notifier_to_errno(NOTIFY_DONE) == 0,
notifier_to_errno(NOTIFY_BAD) == -EPERM)

Forthcoming patches convert several cpu notifiers to return encapsulate
errno value with notifier_from_errno().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2010-05-26 14:43:29 -07:00 committed by Linus Torvalds
parent e9fb7631eb
commit e6bde73b07
1 changed files with 8 additions and 6 deletions
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14
kernel/cpu.c
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@ -137,8 +137,12 @@ int __ref register_cpu_notifier(struct notifier_block *nb)
static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
int *nr_calls)
{
return __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
int ret;
ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
nr_calls);
return notifier_to_errno(ret);
}
static int cpu_notify(unsigned long val, void *v)
@ -151,7 +155,7 @@ static void cpu_notify_nofail(unsigned long val, void *v)
int err;
err = cpu_notify(val, v);
BUG_ON(err == NOTIFY_BAD);
BUG_ON(err);
}
#ifdef CONFIG_HOTPLUG_CPU
@ -232,14 +236,13 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
cpu_hotplug_begin();
set_cpu_active(cpu, false);
err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
if (err == NOTIFY_BAD) {
if (err) {
set_cpu_active(cpu, true);
nr_calls--;
__cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
printk("%s: attempt to take down CPU %u failed\n",
__func__, cpu);
err = -EINVAL;
goto out_release;
}
@ -304,11 +307,10 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
cpu_hotplug_begin();
ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
if (ret == NOTIFY_BAD) {
if (ret) {
nr_calls--;
printk("%s: attempt to bring up CPU %u failed\n",
__func__, cpu);
ret = -EINVAL;
goto out_notify;
}