linux-kernel - Re: [PATCH v5 01/22] bootconfig: Add Extra Boot Config support

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Message-Id: <20200108141700.425599efe7ab0ac7c4329661@kernel.org>
Date:   Wed, 8 Jan 2020 14:17:00 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Frank Rowand <frowand.list@...il.com>,
        Ingo Molnar <mingo@...hat.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Tim Bird <Tim.Bird@...y.com>, Jiri Olsa <jolsa@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Rob Herring <robh+dt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Jonathan Corbet <corbet@....net>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-doc@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 01/22] bootconfig: Add Extra Boot Config support

Hi Steve,

On Tue, 7 Jan 2020 20:59:45 -0500
Steven Rostedt <rostedt@...dmis.org> wrote:

> On Thu, 26 Dec 2019 23:04:00 +0900
> Masami Hiramatsu <mhiramat@...nel.org> wrote:
> 
> 
> > +/**
> > + * xbc_node_is_value() - Test the node is a value node
> > + * @node: An XBC node.
> > + *
> > + * Test the @node is a value node and return true if a value node, false if not.
> > + */
> > +static inline __init bool xbc_node_is_value(struct xbc_node *node)
> > +{
> > +	return !!(node->data & XBC_VALUE);
> 
> The "!!" is not needed, as this is a static inline bool function. The
> compiler will make this a 1 or 0 without it.
> 
> 	return node->data & XBC_VALUE;
> 
> is sufficient.

OK.

> 
> > +}
> > +
> > +/**
> > + * xbc_node_is_key() - Test the node is a key node
> > + * @node: An XBC node.
> > + *
> > + * Test the @node is a key node and return true if a key node, false if not.
> > + */
> > +static inline __init bool xbc_node_is_key(struct xbc_node *node)
> > +{
> > +	return !(node->data & XBC_VALUE);
> > +}
> > +

Maybe this is better use xbc_node_is_value()

	return !xbc_node_is_value();

Right?

> > +
> > +/*
> > + * Return delimiter or error, no node added. As same as lib/cmdline.c,
> > + * you can use " around spaces, but can't escape " for value.
> > + */
> > +static int __init __xbc_parse_value(char **__v, char **__n)
> > +{
> > +	char *p, *v = *__v;
> > +	int c, quotes = 0;
> > +
> > +	v = skip_spaces(v);
> > +	while (*v == '#') {
> > +		v = skip_comment(v);
> > +		v = skip_spaces(v);
> > +	}
> > +	if (*v == '"' || *v == '\'') {
> > +		quotes = *v;
> > +		v++;
> > +	}
> > +	p = v - 1;
> > +	while ((c = *++p)) {
> > +		if (!isprint(c) && !isspace(c))
> > +			return xbc_parse_error("Non printable value", p);
> > +		if (quotes) {
> > +			if (c != quotes)
> > +				continue;
> > +			quotes = 0;
> > +			*p++ = '\0';
> > +			p = skip_spaces(p);
> 
> Hmm, if p here == "    \0" then skip_spaces() will make p == "\0"
> 
> > +			c = *p;
> > +			if (c && !strchr(",;\n#}", c))
> > +				return xbc_parse_error("No value delimiter", p);
> > +			p++;
> 
> Now p == one passed "\0" which is in unknown territory.

Ah, right!

> 
> > +			break;
> > +		}
> > +		if (strchr(",;\n#}", c)) {
> 
> Also, why are we looking at '\n'? as wouldn't that get skipped by
> skip_spaces() too?

I forgot that '\n' is also isspace() true...

Thank you!

> 
> -- Steve
> 
> > +			v = strim(v);
> > +			*p++ = '\0';
> > +			break;
> > +		}
> > +	}
> > +	if (quotes)
> > +		return xbc_parse_error("No closing quotes", p);
> > +	if (c == '#') {
> > +		p = skip_comment(p);
> > +		c = *p;
> > +	}
> > +	*__n = p;
> > +	*__v = v;
> > +
> > +	return c;
> > +}
> > +


-- 
Masami Hiramatsu <mhiramat@...nel.org>