linux-kernel - Re: [PATCH V4 4/4] x86/resctrl: Use appropriate API for strings terminated by newline

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Date:   Mon, 18 May 2020 14:50:26 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Reinette Chatre <reinette.chatre@...el.com>
Cc:     tglx@...utronix.de, fenghua.yu@...el.com, bp@...en8.de,
        tony.luck@...el.com, kuo-lang.tseng@...el.com,
        ravi.v.shankar@...el.com, mingo@...hat.com, babu.moger@....com,
        hpa@...or.com, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V4 4/4] x86/resctrl: Use appropriate API for strings
 terminated by newline

On Sat, May 16, 2020 at 11:28:41AM -0700, Reinette Chatre wrote:
> The user input to files in the resctrl filesystem are expected to be
> terminated with a newline. Testing the user input includes a test for
> the presence of a newline and then replacing the newline with NUL
> byte followed by comparison using strcmp().
> 
> sysfs_streq() exists to test if strings are equal, treating both NUL and
> newline-then-NUL as equivalent string terminations. Even more,
> sysfs_match_string() exists to match a given string in an array using
> sysfs_streq().
> 
> Replace existing strcmp() comparisons of strings that are terminated
> with a newline with more appropriate sysfs_streq() via the
> sysfs_match_string() API that can perform the match across the different
> mode strings that are already maintained in an array.

Sorry for late comment, but just have noticed...

>  	if (mode == RDT_MODE_PSEUDO_LOCKED) {
> @@ -1445,14 +1450,14 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
>  		goto out;
>  	}
>  
> -	if (!strcmp(buf, "shareable")) {
> +	if (user_m == RDT_MODE_SHAREABLE) {
>  		if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
>  			ret = rdtgroup_locksetup_exit(rdtgrp);
>  			if (ret)
>  				goto out;
>  		}

>  		rdtgrp->mode = RDT_MODE_SHAREABLE;

...can we simple move this and similar (in other branches) to...


> -	} else {
> -		rdt_last_cmd_puts("Unknown or unsupported mode\n");
> -		ret = -EINVAL;
>  	}

...here as

		rdtgrp->mode = user_m;

?

>  out:

Note, I didn't check all branches carefully.

-- 
With Best Regards,
Andy Shevchenko