linux-kernel - Re: [PATCH v8 6/6] powerpc/fadump: use the new parse

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Message-Id: <12256349-cdac-8e66-699f-095873ed2809@linux.vnet.ibm.com>
Date:   Fri, 29 Sep 2017 18:30:13 +0530
From:   Hari Bathini <hbathini@...ux.vnet.ibm.com>
To:     Michal Suchanek <msuchanek@...e.de>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Jonathan Corbet <corbet@....net>, Jessica Yu <jeyu@...nel.org>,
        Rusty Russell <rusty@...tcorp.com.au>,
        Jason Baron <jbaron@...mai.com>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Daniel Axtens <dja@...ens.net>,
        Nicholas Piggin <npiggin@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michael Neuling <mikey@...ling.org>,
        Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>,
        "Sylvain 'ythier' Hitier" <sylvain.hitier@...il.com>,
        David Howells <dhowells@...hat.com>,
        Ingo Molnar <mingo@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Steven Rostedt," <rostedt@...dmis.org>,
        Michal Hocko <mhocko@...e.com>,
        Laura Abbott <lauraa@...eaurora.org>,
        Tejun Heo <tj@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Lokesh Vutla <lokeshvutla@...com>, Baoquan He <bhe@...hat.com>,
        Ilya Matveychikov <matvejchikov@...il.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 6/6] powerpc/fadump: use the new parse_args callback
 arguments

In case, someone wishes for a changelog:


With fadump_rework_cmdline_params() function, parse_args() callback 
function,

taking new arguments - current & next, use them to process 
'fadump_extra_args='

parmeter, in enforcing the parameters passed through it for fadump kernel.


On Tuesday 12 September 2017 09:31 PM, Michal Suchanek wrote:
> Signed-off-by: Michal Suchanek <msuchanek@...e.de>
> ---
>   arch/powerpc/kernel/fadump.c | 47 ++++++++++++--------------------------------
>   1 file changed, 13 insertions(+), 34 deletions(-)
>
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 8778e1cc0380..1678d99ea835 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -481,33 +481,19 @@ struct param_info {
>   };
>
>   static void __init fadump_update_params(struct param_info *param_info,
> -					char *param, char *val)
> +					char *param, char *val,
> +					char *currant, char *next)
>   {
> -	ptrdiff_t param_offset = param - param_info->tmp_cmdline;
> +	ptrdiff_t param_offset = currant - param_info->tmp_cmdline;
>   	size_t vallen = val ? strlen(val) : 0;
>   	char *tgt = param_info->cmdline + param_offset
>   				- param_info->shortening;
> -	int shortening = 0;
> -	int quoted = 0;
> +	int shortening = ((next - 1) - (currant))
> +		- (FADUMP_EXTRA_ARGS_LEN + 1 + vallen);
>
>   	if (!val)
>   		return;
>
> -	/* leading '"' removed from parameter */
> -	if ((param > param_info->tmp_cmdline) && *(param - 1) == '"') {
> -		quoted = 1;
> -		shortening += 1;
> -		tgt--;
> -	}
> -
> -	/* next_arg removes one leading and one trailing '"' */
> -	if ((*(tgt + FADUMP_EXTRA_ARGS_LEN + 1 + vallen + shortening) == '"') &&
> -	    (quoted || (*(tgt + FADUMP_EXTRA_ARGS_LEN + 1) == '"'))) {
> -		shortening += 1;
> -		if (!quoted)
> -			shortening += 1;
> -	}
> -
>   	/* remove one leading and one trailing quote if both are present */
>   	if ((val[0] == '"') && (val[vallen - 1] == '"')) {
>   		shortening += 2;
> @@ -515,22 +501,15 @@ static void __init fadump_update_params(struct param_info *param_info,
>   		val++;
>   	}
>
> -	/* some characters were removed - move the trailing part of cmdline */
> -	if (shortening) {
> -		char *src;
> +	strncpy(tgt, FADUMP_EXTRA_ARGS_PARAM, FADUMP_EXTRA_ARGS_LEN);
> +	tgt += FADUMP_EXTRA_ARGS_LEN;
> +	*tgt++ = ' ';
> +	strncpy(tgt, val, vallen);
> +	tgt += vallen;
>
> -		strncpy(tgt, FADUMP_EXTRA_ARGS_PARAM, FADUMP_EXTRA_ARGS_LEN);
> -		tgt += FADUMP_EXTRA_ARGS_LEN;
> -		*tgt++ = ' ';
> -
> -		strncpy(tgt, val, vallen);
> -		tgt += vallen;
> -
> -		src = tgt + shortening;
> +	if (shortening) {
> +		char *src = tgt + shortening;
>   		memmove(tgt, src, strlen(src) + 1);
> -	} else {
> -		/* remove the '=' */
> -		*(tgt + FADUMP_EXTRA_ARGS_LEN) = ' ';
>   	}
>
>   	param_info->shortening += shortening;
> @@ -550,7 +529,7 @@ static int __init fadump_rework_cmdline_params(char *param, char *val,
>   		     strlen(FADUMP_EXTRA_ARGS_PARAM) - 1))
>   		return 0;
>
> -	fadump_update_params(param_info, param, val);
> +	fadump_update_params(param_info, param, val, currant, next);
>
>   	return 0;
>   }


Thanks
Hari