linux-kernel - [for-next][PATCH] tracing histograms: Simplify parse

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Date: Mon, 8 Jan 2024 19:05:12 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers
 <mathieu.desnoyers@...icios.com>
Subject: [for-next][PATCH] tracing histograms: Simplify parse_actions()
 function


  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace/core

Head SHA1: 4f1991a92cfe89096b2d1f5583a2e093bdd55c37


Steven Rostedt (Google) (1):
      tracing histograms: Simplify parse_actions() function

----
 kernel/trace/trace_events_hist.c | 49 ++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 25 deletions(-)
---------------------------
commit 4f1991a92cfe89096b2d1f5583a2e093bdd55c37
Author: Steven Rostedt (Google) <rostedt@...dmis.org>
Date:   Sun Jan 7 20:32:58 2024 -0500

    tracing histograms: Simplify parse_actions() function
    
    The parse_actions() function uses 'len = str_has_prefix()' to test which
    action is in the string being parsed. But then it goes and repeats the
    logic for each different action. This logic can be simplified and
    duplicate code can be removed as 'len' contains the length of the found
    prefix which should be used for all actions.
    
    Link: https://lore.kernel.org/all/20240107112044.6702cb66@gandalf.local.home/
    Link: https://lore.kernel.org/linux-trace-kernel/20240107203258.37e26d2b@gandalf.local.home
    
    Cc: Masami Hiramatsu <mhiramat@...nel.org>
    Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
    Cc: Andy Shevchenko <andy@...nel.org>
    Cc: Tom Zanussi <zanussi@...nel.org>
    Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5ecf3c8bde20..6ece1308d36a 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -4805,36 +4805,35 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 	int len;
 
 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
+		enum handler_id hid = 0;
+		char *action_str;
+
 		str = hist_data->attrs->action_str[i];
 
-		if ((len = str_has_prefix(str, "onmatch("))) {
-			char *action_str = str + len;
+		if ((len = str_has_prefix(str, "onmatch(")))
+			hid = HANDLER_ONMATCH;
+		else if ((len = str_has_prefix(str, "onmax(")))
+			hid = HANDLER_ONMAX;
+		else if ((len = str_has_prefix(str, "onchange(")))
+			hid = HANDLER_ONCHANGE;
 
-			data = onmatch_parse(tr, action_str);
-			if (IS_ERR(data)) {
-				ret = PTR_ERR(data);
-				break;
-			}
-		} else if ((len = str_has_prefix(str, "onmax("))) {
-			char *action_str = str + len;
+		action_str = str + len;
 
-			data = track_data_parse(hist_data, action_str,
-						HANDLER_ONMAX);
-			if (IS_ERR(data)) {
-				ret = PTR_ERR(data);
-				break;
-			}
-		} else if ((len = str_has_prefix(str, "onchange("))) {
-			char *action_str = str + len;
+		switch (hid) {
+		case HANDLER_ONMATCH:
+			data = onmatch_parse(tr, action_str);
+			break;
+		case HANDLER_ONMAX:
+		case HANDLER_ONCHANGE:
+			data = track_data_parse(hist_data, action_str, hid);
+			break;
+		default:
+			data = ERR_PTR(-EINVAL);
+			break;
+		}
 
-			data = track_data_parse(hist_data, action_str,
-						HANDLER_ONCHANGE);
-			if (IS_ERR(data)) {
-				ret = PTR_ERR(data);
-				break;
-			}
-		} else {
-			ret = -EINVAL;
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
 			break;
 		}