[PATCH v2] tracing: Remove redundant assignment to event_var

From: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
To: rostedt@goodmis.org
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org,
	Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Subject: [PATCH v2] tracing: Remove redundant assignment to event_var
Date: Sat,  8 May 2021 18:37:16 +0800	[thread overview]
Message-ID: <1620470236-26562-1-git-send-email-jiapeng.chong@linux.alibaba.com> (raw)

Variable event_var is set to 'ERR_PTR(-EINVAL)', but this value
is never read as it is overwritten or not used later on, hence
it is a redundant assignment and can be removed.

Clean up the following clang-analyzer warning:

kernel/trace/trace_events_hist.c:2437:21: warning: Value stored to
'event_var' during its initialization is never read
[clang-analyzer-deadcode.DeadStores].

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
Changes in v2:
  -Move the declaration of event_var below key_field, as their names
   are both the same size in length and are of the same type. This
   keeps the "upside-down x-mas tree" look of the declarations. For
   the follow advice: https://lore.kernel.org/patchwork/patch/1422518/

 kernel/trace/trace_events_hist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index c1abd63..dacd6fe 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2434,12 +2434,12 @@ static struct trace_event_file *event_file(struct trace_array *tr,
 		      char *subsys_name, char *event_name, char *field_name)
 {
 	struct trace_array *tr = target_hist_data->event_file->tr;
-	struct hist_field *event_var = ERR_PTR(-EINVAL);
 	struct hist_trigger_data *hist_data;
 	unsigned int i, n, first = true;
 	struct field_var_hist *var_hist;
 	struct trace_event_file *file;
 	struct hist_field *key_field;
+	struct hist_field *event_var;
 	char *saved_filter;
 	char *cmd;
 	int ret;
-- 
1.8.3.1

