Re: [PATCH trace-cmd] trace-cmd report: Ensure filter is applied to single input file

[Steven Rostedt <rostedt@goodmis.org>]

On Fri, 17 Mar 2023 18:24:30 -0300
Gabriel Krisman Bertazi <krisman@suse.de> wrote:

> Since 955d05fc7aee ("trace-cmd report: Make filter arguments match their
> files"), the -F filtering is silently ignored when a trace file is
> provided with -i and the filter comes after -i .  The reason is that the
> filter is now associated with input_files and not saved to the global
> list only in this case, but process_filters still only checks the global
> list when handles->input_file is not set.
> 
> Avoid this by checking last_input_file first, which always contains a
> pointer to the correct filter in this case.
> 
> This was only lightly tested, using a single trace file.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=217038
> Fixes: 955d05fc7aee ("trace-cmd report: Make filter arguments match their files")
> Signed-off-by: Gabriel krisman Bertazi <krisman@suse.de>
> ---
>  tracecmd/trace-read.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/tracecmd/trace-read.c b/tracecmd/trace-read.c
> index 52ba818..dbbd124 100644
> --- a/tracecmd/trace-read.c
> +++ b/tracecmd/trace-read.c
> @@ -567,11 +567,15 @@ static void process_filters(struct handle_list *handles)
>  	struct tracecmd_filter *trace_filter;
>  	struct filter_str *filter;
>  	int filters = 0;
> +	struct input_files *input_file = handles->input_file;

BTW, please keep the "upside-down x-mas tree" formatting of the above.

ie.

static void process_filters(struct handle_list *handles)
{
        struct input_files *input_file = handles->input_file;
        struct tracecmd_filter *trace_filter;
        struct filter_str *filter;
        int filters = 0;


>  
> -	make_pid_filter(handles->handle, handles->input_file);
> +	if (!input_file)
> +		input_file = last_input_file;
>  
> -	if (handles->input_file)
> -		filter = handles->input_file->filter_str;
> +	make_pid_filter(handles->handle, input_file);
> +
> +	if (input_file)
> +		filter = input_file->filter_str;
>  	else
>  		filter = filter_strings;
>  

So I was playing with this, and I actually needed something else.

If an -F comes before *any* file, I think it should be added to *all* files.

That is:

 -F sched_switch -i trace1.dat -i trace2.dat

Should filter sched_switch for both trace1.dat and trace2.dat.

I actually wanted this just a few minutes ago ;-)

Can you do this, or would you want me to?

-- Steve