Re: [PATCH] mm/backing-dev: Check return value of the debugfs_create_dir()

[Jan Kara <jack@suse.cz>]

On Tue 25-08-15 13:54:23, Alexander Kuleshov wrote:
> The debugfs_create_dir() function may fail and return error. If the
> root directory not created, we can't create anything inside it. This
> patch adds check for this case.
> 
> Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>

The patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.com>

								Honza
> ---
>  mm/backing-dev.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index dac5bf5..518d26a 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -117,15 +117,21 @@ static const struct file_operations bdi_debug_stats_fops = {
>  
>  static void bdi_debug_register(struct backing_dev_info *bdi, const char *name)
>  {
> -	bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root);
> -	bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir,
> -					       bdi, &bdi_debug_stats_fops);
> +	if (bdi_debug_root) {
> +		bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root);
> +		if (bdi->debug_dir)
> +			bdi->debug_stats = debugfs_create_file("stats", 0444,
> +							bdi->debug_dir, bdi,
> +							&bdi_debug_stats_fops);
> +	}
>  }
>  
>  static void bdi_debug_unregister(struct backing_dev_info *bdi)
>  {
> -	debugfs_remove(bdi->debug_stats);
> -	debugfs_remove(bdi->debug_dir);
> +	if (bdi_debug_root) {
> +		debugfs_remove(bdi->debug_stats);
> +		debugfs_remove(bdi->debug_dir);
> +	}
>  }
>  #else
>  static inline void bdi_debug_init(void)
> -- 
> 2.5.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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