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

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Date:	Tue, 20 Aug 2013 11:44:31 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	steffen.klassert@...unet.com
CC:	linux-crypto@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kernel/padata.c: always check the return value of __padata_remove_cpu()
 and __padata_add_cpu()


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@...anux.com>
> ---
>  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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