path: root/kernel/cpu.c
diff options
authorAkinobu Mita <akinobu.mita@gmail.com>2010-05-26 14:43:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 09:12:47 -0700
commite6bde73b07edeb703d4c89c1daabc09c303de11f (patch)
tree9b60a3fc2ce002b26e46611357cb5529795e7ac5 /kernel/cpu.c
parente9fb7631ebcdc9467cbb736337546a42f7b7f28e (diff)
cpu-hotplug: return better errno on cpu hotplug failure
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>
Diffstat (limited to 'kernel/cpu.c')
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 09207c772c2..0690ac27a25 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -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,
+ 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);
@@ -232,14 +236,13 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
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);
__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)
ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
- if (ret == NOTIFY_BAD) {
+ if (ret) {
printk("%s: attempt to bring up CPU %u failed\n",
__func__, cpu);
- ret = -EINVAL;
goto out_notify;