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

[guijianfeng@cn.fujitsu.com (Gui Jianfeng)]

Mathieu Desnoyers wrote:
> * 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 ? ;)

  Yes, really have.... :)   Will post v2

> 
> 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
>>
>>
> 

-- 
Regards
Gui Jianfeng