Subject: Re: [PATCH 1/2] Convert /proc/net/ipv6_route to seq_file interface

From: Benjamin Thery <[email-masked]>
Date: Tue, 30 Oct 2007 14:35:20 +0100

Alexey Dobriyan wrote:
> One proc_net_create() user less.

Funny, I was working on a similar patch.

See comment below.

> Signed-off-by: Alexey Dobriyan <[email-masked]>
> ---
> 
>  net/ipv6/route.c |   70 +++++++++++++++++++------------------------------------
>  1 file changed, 25 insertions(+), 45 deletions(-)
> 
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -2288,71 +2288,49 @@ struct rt6_proc_arg
>  
>  static int rt6_info_route(struct rt6_info *rt, void *p_arg)
>  {
> -	struct rt6_proc_arg *arg = (struct rt6_proc_arg *) p_arg;
> +	struct seq_file *m = p_arg;
>  
> -	if (arg->skip < arg->offset / RT6_INFO_LEN) {
> -		arg->skip++;
> -		return 0;
> -	}
> -
> -	if (arg->len >= arg->length)
> -		return 0;
> -
> -	arg->len += sprintf(arg->buffer + arg->len,
> -			    NIP6_SEQFMT " %02x ",
> -			    NIP6(rt->rt6i_dst.addr),
> +	seq_printf(m, NIP6_SEQFMT " %02x ", NIP6(rt->rt6i_dst.addr),
>  			    rt->rt6i_dst.plen);
>  
>  #ifdef CONFIG_IPV6_SUBTREES
> -	arg->len += sprintf(arg->buffer + arg->len,
> -			    NIP6_SEQFMT " %02x ",
> -			    NIP6(rt->rt6i_src.addr),
> +	seq_printf(m, NIP6_SEQFMT " %02x ", NIP6(rt->rt6i_src.addr),
>  			    rt->rt6i_src.plen);
>  #else
> -	arg->len += sprintf(arg->buffer + arg->len,
> -			    "00000000000000000000000000000000 00 ");
> +	seq_puts(m, "00000000000000000000000000000000 00 ");
>  #endif
>  
>  	if (rt->rt6i_nexthop) {
> -		arg->len += sprintf(arg->buffer + arg->len,
> -				    NIP6_SEQFMT,
> +		seq_printf(m, NIP6_SEQFMT,
>  				    NIP6(*((struct in6_addr *)rt->rt6i_nexthop->primary_key)));
>  	} else {
> -		arg->len += sprintf(arg->buffer + arg->len,
> -				    "00000000000000000000000000000000");
> +		seq_puts(m, "00000000000000000000000000000000");
>  	}
> -	arg->len += sprintf(arg->buffer + arg->len,
> -			    " %08x %08x %08x %08x %8s\n",
> +	seq_printf(m, " %08x %08x %08x %08x %8s\n",
>  			    rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
>  			    rt->u.dst.__use, rt->rt6i_flags,
>  			    rt->rt6i_dev ? rt->rt6i_dev->name : "");
>  	return 0;
>  }
>  
> -static int rt6_proc_info(char *buffer, char **start, off_t offset, int length)
> +static int ipv6_route_show(struct seq_file *m, void *v)
>  {
> -	struct rt6_proc_arg arg = {
> -		.buffer = buffer,
> -		.offset = offset,
> -		.length = length,
> -	};
> -
> -	fib6_clean_all(rt6_info_route, 0, &arg);
> -
> -	*start = buffer;
> -	if (offset)
> -		*start += offset % RT6_INFO_LEN;
> -
> -	arg.len -= offset % RT6_INFO_LEN;
> -
> -	if (arg.len > length)
> -		arg.len = length;
> -	if (arg.len < 0)
> -		arg.len = 0;
> +	fib6_clean_all(rt6_info_route, 0, m);
> +	return 0;
> +}
>  
> -	return arg.len;
> +static int ipv6_route_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, ipv6_route_show, NULL);
>  }
>  
> +static const struct file_operations ipv6_route_proc_fops = {
> +	.open		= ipv6_route_open,
> +	.read		= seq_read,
> +	.llseek		= seq_lseek,
> +	.release	= single_release,
> +};
> +
>  static int rt6_stats_seq_show(struct seq_file *seq, void *v)
>  {
>  	seq_printf(seq, "%04x %04x %04x %04x %04x %04x %04x\n",
> @@ -2499,9 +2477,11 @@ void __init ip6_route_init(void)
>  
>  	fib6_init();
>  #ifdef 	CONFIG_PROC_FS
> -	p = proc_net_create(&init_net, "ipv6_route", 0, rt6_proc_info);
> -	if (p)

> +	p = create_proc_entry("ipv6_route", 0, init_net.proc_net);
> +	if (p) {
>  		p->owner = THIS_MODULE;
> +		p->proc_fops = &ipv6_route_proc_fops;
> +	}

You should use proc_net_fops_create() instead of the above code. 
It does the same thing.

Otherwise the patch looks fine to me.
Tested on i386.

Benjamin

>  	proc_net_fops_create(&init_net, "rt6_stats", S_IRUGO, &rt6_stats_seq_fops);
>  #endif
> 
> -
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