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Date: Wed, 5 Jun 2024 11:15:38 +0100
From: Mark Rutland <mark.rutland@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/5] ftrace: Comment __ftrace_hash_rec_update() and make
 filter_hash bool
Message-ID: <ZmA6ygUWNPkq0PKV@J2N7QTR9R3>
References: <20240604212817.384103202@goodmis.org>
 <20240604212854.725383717@goodmis.org>
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In-Reply-To: <20240604212854.725383717@goodmis.org>

On Tue, Jun 04, 2024 at 05:28:19PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> The function __ftrace_hash_rec_update() parameter "filter_hash" is only
> used for true or false (boolean), but is of type int. It already has an
> "inc" parameter that is boolean. This is confusing, make "filter_hash"
> boolean as well.
> 
> While at it, add some documentation to that function especially since it
> holds the guts of the filtering logic of ftrace.
> 
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  kernel/trace/ftrace.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 9dcdefe9d1aa..93c7c5fd4249 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -1701,8 +1701,20 @@ static bool skip_record(struct dyn_ftrace *rec)
>  		!(rec->flags & FTRACE_FL_ENABLED);
>  }
>  
> +/*
> + * This is the main engine to the ftrace updates.
> + *
> + * It will iterate through all the available ftrace functions
> + * (the ones that ftrace can have callbacks to) and set the flags
> + * to the associated dyn_ftrace records.

I beleive s/to/in/ here, to make this one of:

	set the flags in the associated dyn_ftrace records.

... rather than:

	set the flags to the associated dyn_ftrace records.

> + *
> + * @filter_hash: True if for the filter hash is udpated, false for the
> + *               notrace hash

Typo: s/udpated/updated/

... though I couldn't parse this regardless; maybe:

	@filter_hash: true to update the filter hash, false to update
		      the notrace hash

Mark.

> + * @inc: True to add this hash, false to remove it (increment the
> + *       recorder counters or decrement them).
> + */
>  static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
> -				     int filter_hash,
> +				     bool filter_hash,
>  				     bool inc)
>  {
>  	struct ftrace_hash *hash;
> -- 
> 2.43.0
> 
>