Re: [PATCH] kernel/padata.c: always check the return value of __padata_remove_cpu()and __padata_add_cpu()

From: Chen Gang
Date: Mon Aug 19 2013 - 23:45:38 EST



If this patch is correct, better to let CPU_ONLINE and CPU_DOWN_FAILED
share the same code.

And do we need a comment "/* fall through */" between CPU_UP_CANCELED
and CPU_DOWN_FAILED (or it is another bug, need a 'break' statement) ?

At last, also better to let CPU_DOWN_PREPARE and CPU_UP_CANCELED share
the same code (if need a 'break'), or share the most of code (if "fall
through").

Thanks.

On 08/20/2013 11:43 AM, Chen Gang wrote:
> When failure occures, __padata_add_cpu() and __padata_remove_cpu() will
> return -ENOMEM, which need be noticed in any cases (even in cleaning up
> cases).
>
> Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
> ---
> kernel/padata.c | 8 ++++++--
> 1 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/padata.c b/kernel/padata.c
> index 072f4ee..6a124cd 100644
> --- a/kernel/padata.c
> +++ b/kernel/padata.c
> @@ -871,16 +871,20 @@ static int padata_cpu_callback(struct notifier_block *nfb,
> if (!pinst_has_cpu(pinst, cpu))
> break;
> mutex_lock(&pinst->lock);
> - __padata_remove_cpu(pinst, cpu);
> + err = __padata_remove_cpu(pinst, cpu);
> mutex_unlock(&pinst->lock);
> + if (err)
> + return notifier_from_errno(err);
>
> case CPU_DOWN_FAILED:
> case CPU_DOWN_FAILED_FROZEN:
> if (!pinst_has_cpu(pinst, cpu))
> break;
> mutex_lock(&pinst->lock);
> - __padata_add_cpu(pinst, cpu);
> + err = __padata_add_cpu(pinst, cpu);
> mutex_unlock(&pinst->lock);
> + if (err)
> + return notifier_from_errno(err);
> }
>
> return NOTIFY_OK;
>


--
Chen Gang
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