linux-kernel - Re: [PATCH 3/4] kmod: Return directly if module name is empty in request

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Message-ID: <20200418054519.GX11244@42.do-not-panic.com>
Date:   Sat, 18 Apr 2020 05:45:19 +0000
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>
Cc:     Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org, Xuefeng Li <lixuefeng@...ngson.cn>
Subject: Re: [PATCH 3/4] kmod: Return directly if module name is empty in
 request_module()

On Sat, Apr 18, 2020 at 01:19:59PM +0800, Tiezhu Yang wrote:
> If module name is empty, it is better to return directly at the beginning
> of request_module() without doing the needless call_modprobe() operation.
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> ---
>  kernel/kmod.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/kernel/kmod.c b/kernel/kmod.c
> index 3cd075c..5851444 100644
> --- a/kernel/kmod.c
> +++ b/kernel/kmod.c
> @@ -28,6 +28,8 @@
>  
>  #include <trace/events/module.h>
>  
> +#define MODULE_NOT_FOUND 256
> +
>  /*
>   * Assuming:
>   *
> @@ -144,6 +146,9 @@ int __request_module(bool wait, const char *fmt, ...)
>  	if (ret >= MODULE_NAME_LEN)
>  		return -ENAMETOOLONG;
>  
> +	if (strlen(module_name) == 0)
> +		return MODULE_NOT_FOUND;

I'd rather we just use something standard like -EINVAL.
What do we return if its not found? Then use that value.

> +
>  	ret = security_kernel_module_request(module_name);
>  	if (ret)
>  		return ret;
> -- 
> 2.1.0
>