Re: [PATCH v2] PM / wakeup: use seq_open() to show wakeup stats

[Andy Shevchenko]

On Mon, Mar 5, 2018 at 10:47 AM, Ganesh Mahendran
<opensource.ganesh@xxxxxxxxx> wrote:
> single_open() interface requires that the whole output must
> fit into a single buffer. This will lead to timeout when
> system memory is not in a good situation.
>
> This patch use seq_open() to show wakeup stats. This method
> need only one page, so timeout will not be observed.

> +       if (n == 0) {
> +               seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
> +                       "expire_count\tactive_since\ttotal_time\tmax_time\t"
> +                       "last_change\tprevent_suspend_time\n");
> +       }

Can't you do this once at ->open() stage, for example?

>  static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
>  {
> -       return single_open(file, wakeup_sources_stats_show, NULL);
> +       return seq_open_private(file, &wakeup_sources_stats_seq_ops, sizeof(int));
>  }

-- 
With Best Regards,
Andy Shevchenko