Re: [PATCH] tracing/histograms: Simplify last_cmd_set()

[Mukesh Ojha]

On 10/21/2023 8:12 PM, Christophe JAILLET wrote:

Turn a kzalloc()+strcpy()+strncat() into an equivalent and less verbose
kasprintf().

Signed-off-by: Christophe JAILLET <christophe.jail...@wanadoo.fr>
---
  kernel/trace/trace_events_hist.c | 11 ++---------
  1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index d06938ae0717..1abc07fba1b9 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -774,23 +774,16 @@ static void last_cmd_set(struct trace_event_file *file, 
char *str)
  {
        const char *system = NULL, *name = NULL;
        struct trace_event_call *call;
-       int len;

if (!str)

                return;

- /* sizeof() contains the nul byte */

-       len = sizeof(HIST_PREFIX) + strlen(str);
        kfree(last_cmd);
-       last_cmd = kzalloc(len, GFP_KERNEL);
+
+       last_cmd = kasprintf(GFP_KERNEL, HIST_PREFIX "%s", str);
        if (!last_cmd)
                return;

- strcpy(last_cmd, HIST_PREFIX);

-       /* Again, sizeof() contains the nul byte */
-       len -= sizeof(HIST_PREFIX);
-       strncat(last_cmd, str, len);

LGTM, careful optimization., Thanks.
Reviewed-by: Mukesh ojha <quic_mo...@quicinc.com>


-Mukesh

-
        if (file) {
                call = file->event_call;
                system = call->class->system;