Re: [PATCH] mtd: fix memory leaks in phram_setup

[Jörn Engel]

On Sun, 14 May 2006 12:03:49 +0100, David Woodhouse wrote:
> On Sun, 2006-05-14 at 08:37 +0200, Jörn Engel wrote:
> > The only question is: does it make the code better?  The code has
> > seven printk/return combinations.  Each of them would chew up 2 more
> > lines without the macro.  So phram_setup would grow from 44 to 58
> > lines, not nice either.
> 
> How about this then...

Moving the printk into leaf functions?  My plan still is to collect a
bunch of those and put somewhere in lib/.  So maybe that's a bad idea.

Apart from that, I don't have a strong opinion.  The macro sucks.
Long functions suck.  Looks about the same to me.  If you care enough
to get rid of the macro, go ahead.

> diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
> index e09e416..fd2d43f 100644
> --- a/drivers/mtd/devices/phram.c
> +++ b/drivers/mtd/devices/phram.c
> @@ -187,36 +187,41 @@ static int ustrtoul(const char *cp, char
>  	return result;
>  }
>  
> -static int parse_num32(uint32_t *num32, const char *token)
> +static int parse_num32(uint32_t *num32, const char *token, char *name)
>  {
>  	char *endp;
>  	unsigned long n;
>  
>  	n = ustrtoul(token, &endp, 0);
> -	if (*endp)
> +	if (*endp) {
> +		ERROR("Illegal %s\n", name);
>  		return -EINVAL;
> +	}
>  
>  	*num32 = n;
>  	return 0;
>  }
>  
> -static int parse_name(char **pname, const char *token)
> +static char *parse_name(const char *token)
>  {
>  	size_t len;
>  	char *name;
>  
>  	len = strlen(token) + 1;
> -	if (len > 64)
> -		return -ENOSPC;
> +	if (len > 64) {
> +		ERROR("name too long");
> +		return ERR_PTR(-ENOSPC);
> +	}
>  
>  	name = kmalloc(len, GFP_KERNEL);
> -	if (!name)
> -		return -ENOMEM;
> +	if (!name) {
> +		ERROR("out of memory");
> +		return ERR_PTR(-ENOMEM);
> +	}
>  
>  	strcpy(name, token);
>  
> -	*pname = name;
> -	return 0;
> +	return name;
>  }
>  
>  
> @@ -228,11 +233,6 @@ static inline void kill_final_newline(ch
>  }
>  
>  
> -#define parse_err(fmt, args...) do {	\
> -	ERROR(fmt , ## args);	\
> -	return 0;		\
> -} while (0)
> -
>  static int phram_setup(const char *val, struct kernel_param *kp)
>  {
>  	char buf[64+12+12], *str = buf;
> @@ -242,8 +242,10 @@ static int phram_setup(const char *val, 
>  	uint32_t len;
>  	int i, ret;
>  
> -	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
> -		parse_err("parameter too long\n");
> +	if (strnlen(val, sizeof(buf)) >= sizeof(buf)) {
> +		ERROR("parameter too long\n");
> +		return -EINVAL;
> +	}
>  
>  	strcpy(str, val);
>  	kill_final_newline(str);
> @@ -251,30 +253,24 @@ static int phram_setup(const char *val, 
>  	for (i=0; i<3; i++)
>  		token[i] = strsep(&str, ",");
>  
> -	if (str)
> -		parse_err("too many arguments\n");
> -
> -	if (!token[2])
> -		parse_err("not enough arguments\n");
> -
> -	ret = parse_name(&name, token[0]);
> -	if (ret == -ENOMEM)
> -		parse_err("out of memory\n");
> -	if (ret == -ENOSPC)
> -		parse_err("name too long\n");
> -	if (ret)
> -		return 0;
> +	if (str) {
> +		ERROR("too many arguments\n");
> +		return -EINVAL;
> +	}
>  
> -	ret = parse_num32(&start, token[1]);
> -	if (ret) {
> -		kfree(name);
> -		parse_err("illegal start address\n");
> +	if (!token[2]) {
> +		ERROR("not enough arguments\n");
> +		return -EINVAL;
>  	}
>  
> -	ret = parse_num32(&len, token[2]);
> -	if (ret) {
> +	name = prase_name(token[0]);
> +	if (IS_ERR(name))
> +	    return PTR_ERR(name);
> +
> +	if ((ret = parse_num32(&start, token[1], "start address")) ||
> +	    (ret = parse_num32(&len, token[2], "device length"))) {
>  		kfree(name);
> -		parse_err("illegal device length\n");
> +		return ret;
>  	}
>  
>  	register_device(name, start, len);
> 
> -- 
> dwmw2

Jörn

-- 
Correctness comes second.
Features come third.
Performance comes last.
Maintainability is needed for all of them.
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