Subject: Re: [PATCH v2] PowerPC: kernel: need return the related error code when failure occurs

From: Chen Gang <[email-masked]>
Date: Sat, 22 Jun 2013 12:08:47 +0800

Hello Maintainers:

Please help check this patch whether is OK, when you have time.

Thanks.

On 05/21/2013 05:20 PM, Chen Gang wrote:
>
> When error occurs, need return the related error code to let upper
> caller know about it.
>
> ppc_md.nvram_size() can return the error code (e.g. core99_nvram_size()
> in 'arch/powerpc/platforms/powermac/nvram.c').
>
> Also set ret value when only need it, so can save structions for normal
> cases.
>
> The original related patch: "f9ce299 [PATCH] powerpc: fix large nvram
> access".
>
>
> Signed-off-by: Chen Gang <[email-masked]>
> ---
>  arch/powerpc/kernel/nvram_64.c |   20 ++++++++++++++------
>  1 files changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
> index 48fbc2b..8213ee1 100644
> --- a/arch/powerpc/kernel/nvram_64.c
> +++ b/arch/powerpc/kernel/nvram_64.c
> @@ -84,22 +84,30 @@ static ssize_t dev_nvram_read(struct file *file, char __user *buf,
>  	char *tmp = NULL;
>  	ssize_t size;
>  
> -	ret = -ENODEV;
> -	if (!ppc_md.nvram_size)
> +	if (!ppc_md.nvram_size) {
> +		ret = -ENODEV;
>  		goto out;
> +	}
>  
> -	ret = 0;
>  	size = ppc_md.nvram_size();
> -	if (*ppos >= size || size < 0)
> +	if (size < 0) {
> +		ret = size;
> +		goto out;
> +	}
> +
> +	if (*ppos >= size) {
> +		ret = 0;
>  		goto out;
> +	}
>  
>  	count = min_t(size_t, count, size - *ppos);
>  	count = min(count, PAGE_SIZE);
>  
> -	ret = -ENOMEM;
>  	tmp = kmalloc(count, GFP_KERNEL);
> -	if (!tmp)
> +	if (!tmp) {
> +		ret = -ENOMEM;
>  		goto out;
> +	}
>  
>  	ret = ppc_md.nvram_read(tmp, count, ppos);
>  	if (ret <= 0)
>

Thanks
-- 
Chen Gang

Asianux Corporation