Messages in this thread Patch in this message | | | From | Akinobu Mita <> | Subject | [PATCH 02/12] cpu-hotplug: return better errno on cpu hotplug failure | Date | Thu, 18 Mar 2010 18:05:14 +0900 |
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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> --- kernel/cpu.c | 14 ++++++++------ 1 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c index bc9c301..d3f335e 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -136,8 +136,12 @@ 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) @@ -150,7 +154,7 @@ 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 @@ -230,14 +234,13 @@ 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; } @@ -314,11 +317,10 @@ 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; } -- 1.6.0.6
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