[PATCH 15/61] trace: Prefer IS_ERR_OR_NULL over manual NULL check

[Steven Rostedt]

On Tue, 10 Mar 2026 12:48:41 +0100
Philipp Hahn <phahn-oss at avm.de> wrote:

> Prefer using IS_ERR_OR_NULL() over using IS_ERR() and a manual NULL
> check.

Why?

> 
> Change generated with coccinelle.
> 
> To: Steven Rostedt <rostedt at goodmis.org>
> To: Masami Hiramatsu <mhiramat at kernel.org>
> To: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> Cc: linux-kernel at vger.kernel.org
> Cc: linux-trace-kernel at vger.kernel.org
> Signed-off-by: Philipp Hahn <phahn-oss at avm.de>
> ---
>  kernel/trace/fprobe.c                | 2 +-
>  kernel/trace/kprobe_event_gen_test.c | 2 +-
>  kernel/trace/trace_events_hist.c     | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
> index dcadf1d23b8a31f571392d0c49cbd22df1716b4f..a94ce810d83b90f55d1178a9bd29c78fd068df4c 100644
> --- a/kernel/trace/fprobe.c
> +++ b/kernel/trace/fprobe.c
> @@ -607,7 +607,7 @@ static int fprobe_module_callback(struct notifier_block *nb,
>  	do {
>  		rhashtable_walk_start(&iter);
>  
> -		while ((node = rhashtable_walk_next(&iter)) && !IS_ERR(node))
> +		while (!IS_ERR_OR_NULL((node = rhashtable_walk_next(&iter))))

Ug, No!

That looks so much worse than the original.

-- Steve

>  			fprobe_remove_node_in_module(mod, node, &alist);
>  
>  		rhashtable_walk_stop(&iter);
> diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
> index 5a4b722b50451bfdee42769a6d3be39c055690d1..a1735ca273f0b756aa1fcfcdab30ddad9bc51c5f 100644
> --- a/kernel/trace/kprobe_event_gen_test.c
> +++ b/kernel/trace/kprobe_event_gen_test.c
> @@ -75,7 +75,7 @@ static struct trace_event_file *gen_kretprobe_test;
>  
>  static bool trace_event_file_is_valid(struct trace_event_file *input)
>  {
> -	return input && !IS_ERR(input);
> +	return !IS_ERR_OR_NULL(input);
>  }
>  
>  /*
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 73ea180cad555898693e92ee397a1c9493c7c167..59df215e1dfd9349eca1c0823ed709ec7285f766 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -3973,7 +3973,7 @@ trace_action_create_field_var(struct hist_trigger_data *hist_data,
>  	 */
>  	field_var = create_target_field_var(hist_data, system, event, var);
>  
> -	if (field_var && !IS_ERR(field_var)) {
> +	if (!IS_ERR_OR_NULL(field_var)) {
>  		save_field_var(hist_data, field_var);
>  		hist_field = field_var->var;
>  	} else {
>