[ltt-dev] [PATCH] lttng: remove ltt root directory if it's no needed

[Mathieu Desnoyers]

* Gui Jianfeng (guijianfeng at cn.fujitsu.com) wrote:
> We have to cleanup the lttng's root directory of debugfs if 
> there is nobody uses it any more.
> 
> This patch is based on 2.6.29-rc3-lttng-0.92.
> 
> Signed-off-by: Gui Jianfeng <guijianfeng at cn.fujitsu.com>
> ---
>  include/linux/ltt-core.h  |    1 +
>  ltt/ltt-core.c            |    7 +++++++
>  ltt/ltt-trace-control.c   |   11 +++++++++++
>  ltt/ltt-userspace-event.c |   10 ++++++++++
>  4 files changed, 29 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/ltt-core.h b/include/linux/ltt-core.h
> index bc244c6..e43fc52 100644
> --- a/include/linux/ltt-core.h
> +++ b/include/linux/ltt-core.h
> @@ -30,6 +30,7 @@ extern struct ltt_traces ltt_traces;
>  /*
>   * get dentry of ltt's root dir
>   */
> +void reset_ltt_root(void);
>  struct dentry *get_ltt_root(void);
>  
>  /* Keep track of trap nesting inside LTT */
> diff --git a/ltt/ltt-core.c b/ltt/ltt-core.c
> index 18db91d..26c04b5 100644
> --- a/ltt/ltt-core.c
> +++ b/ltt/ltt-core.c
> @@ -23,6 +23,13 @@ static DEFINE_MUTEX(ltt_traces_mutex);
>  
>  /* dentry of ltt's root dir */
>  static struct dentry *ltt_root_dentry;
> +
> +void reset_ltt_root(void)
> +{
> +	ltt_root_dentry = NULL;
> +}
> +EXPORT_SYMBOL_GPL(reset_ltt_root);
> +
>  struct dentry *get_ltt_root(void)
>  {
>  	if (!ltt_root_dentry) {
> diff --git a/ltt/ltt-trace-control.c b/ltt/ltt-trace-control.c
> index 16502a2..21416b1 100644
> --- a/ltt/ltt-trace-control.c
> +++ b/ltt/ltt-trace-control.c
> @@ -740,6 +740,10 @@ err_create_destroy_trace_file:
>  err_create_setup_trace_file:
>  	debugfs_remove(ltt_control_dir);
>  err_create_control_dir:
> +	if (list_empty(&ltt_root_dentry->d_subdirs)) {
> +		debugfs_remove(ltt_root_dentry);
> +		reset_ltt_root();
> +	}
>  err_no_root:
>  	return err;
>  }
> @@ -747,6 +751,9 @@ err_no_root:
>  static void __exit ltt_trace_control_exit(void)
>  {
>  	struct dentry *trace_dir;
> +	struct dentry *ltt_root_dentry;
> +
> +	ltt_root_dentry = get_ltt_root();
>  
>  	/* destory all traces */
>  	list_for_each_entry(trace_dir, &ltt_control_dir->d_subdirs,
> @@ -759,6 +766,10 @@ static void __exit ltt_trace_control_exit(void)
>  	debugfs_remove(ltt_setup_trace_file);
>  	debugfs_remove(ltt_destroy_trace_file);
>  	debugfs_remove_recursive(ltt_control_dir);
> +	if (list_empty(&ltt_root_dentry->d_subdirs)) {
> +		debugfs_remove(ltt_root_dentry);
> +		reset_ltt_root();
> +	}

Hi Gui,

Don't you have the feeling of doing cut'n'paste here ? ;)

Please move the code above in put_ltt_root in ltt-core.c.

Mathieu

>  }
>  
>  module_init(ltt_trace_control_init);
> diff --git a/ltt/ltt-userspace-event.c b/ltt/ltt-userspace-event.c
> index 385bd3b..ef4fbb2 100644
> --- a/ltt/ltt-userspace-event.c
> +++ b/ltt/ltt-userspace-event.c
> @@ -117,7 +117,17 @@ err_no_root:
>  
>  static void __exit ltt_userspace_exit(void)
>  {
> +	struct dentry *ltt_root_dentry;
> +
> +	ltt_root_dentry = get_ltt_root();
> +
>  	debugfs_remove(ltt_event_file);
> +	if (ltt_root_dentry) {
> +		if (list_empty(&ltt_root_dentry->d_subdirs)) {
> +			debugfs_remove(ltt_root_dentry);
> +			reset_ltt_root();
> +		}
> +	}
>  }
>  
>  module_init(ltt_userspace_init);
> -- 
> 1.5.4.rc3
> 
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68