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From: Jerome Marchand <jmarchan@redhat.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Pavel Emelyanov <xemul@parallels.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	xiyou.wangcong@gmail.com
Subject: Re: [PATCH v2] procfs: fix numbering in /proc/locks
Date: Tue, 05 Oct 2010 14:14:11 +0200	[thread overview]
Message-ID: <4CAB1693.2080301@redhat.com> (raw)
In-Reply-To: <4CA484BA.7090809@redhat.com>

On 09/30/2010 02:38 PM, Jerome Marchand wrote:
> 
> The lock number in /proc/locks (first field) is implemented by a counter
> (private field of struct seq_file) which is incremented at each call of
> locks_show() and reset to 1 in locks_start() whatever the offset is. It
> should be reset according to the actual position in the list.
> 
> Moreover, locks_show() can be called twice to print a single line thus
> skipping a number. The counter should be incremented in locks_next().
> 
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
> ---
>  locks.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index ab24d49..49d7343 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2166,19 +2166,19 @@ static int locks_show(struct seq_file *f, void *v)
>  	list_for_each_entry(bfl, &fl->fl_block, fl_block)
>  		lock_get_status(f, bfl, (long)f->private, " ->");
>  
> -	f->private++;
>  	return 0;
>  }
>  
>  static void *locks_start(struct seq_file *f, loff_t *pos)
>  {
>  	lock_kernel();
> -	f->private = (void *)1;
> +	f->private = (void *) (*pos + 1);

That cast trigger a warning on some arch:
"warning: cast to pointer from integer of different size"

There is no real risk here. At worst /proc/locks will show wrong number
if there is more than 2^32 locks, but should I mute the warning it with
something like:
        f->private = (void *) (size_t) (*pos + 1);
?

Thanks,
Jerome

>  	return seq_list_start(&file_lock_list, *pos);
>  }
>  
>  static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
>  {
> +	f->private++;
>  	return seq_list_next(v, &file_lock_list, pos);
>  }
>  
> --
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  parent reply	other threads:[~2010-10-05 12:14 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-30 12:38 [PATCH v2] procfs: fix numbering in /proc/locks Jerome Marchand
2010-10-01  7:03 ` Américo Wang
2010-10-01  7:13 ` Pavel Emelyanov
2010-10-05 12:14 ` Jerome Marchand [this message]
2010-10-06 10:36   ` Américo Wang
2010-10-07 23:27   ` Andrew Morton
2010-10-08  8:29     ` Jerome Marchand
2010-10-15 11:32     ` [PATCH v3] " Jerome Marchand
2010-10-22 21:27       ` Andrew Morton

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