From nobody Fri Dec 19 15:44:27 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B996C16D9C2; Thu, 6 Nov 2025 00:34:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762389292; cv=none; b=lEB1akVzS3TtgVvaw2EtnNikS5cSdlQIYdoUFnqt5YW0CWV7G8xxN/Y/t0VEFQ7TNhzjo3x99hEZ3xlRc9iBY5QHnbzfdq6Ef4gpr49oMWgtHCPzPDM1bofGCwt/x52HAA+DxnaoWwstX8IX7om0iTE0Za0EfYSPP9P1KhXcwjs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762389292; c=relaxed/simple; bh=Ql+H8A5+GMaJkE7Zpv0T+FJ4Id1te48MhyUNdLkw2bg=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=aGxySezGCLFrjRdXrKqewujuk5E3W8xMTGX0buQRGCUZekmGHLdSK4fz1B3mzs4EaaRqkqIVQ3xXvUpooD4vsJge+CnZnTHDpiRfWcfznEJwkAKK31+DMx9UA00XLT1nEVid4x5nEcCWFHUD9HWzG/L5T1NEc9p+3iT9O72CmlQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XJdfXsBf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XJdfXsBf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A231C116D0; Thu, 6 Nov 2025 00:34:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762389292; bh=Ql+H8A5+GMaJkE7Zpv0T+FJ4Id1te48MhyUNdLkw2bg=; h=Date:From:To:Cc:Subject:References:From; b=XJdfXsBfMyWba9m8O6tTXKDOt+ytO0b+ClVo6ci4aPOsR402kL9boqh9dZrbQaUNu 820+AaZ7WqAc97BCKM8rjOG6NburzUeFZ/NF9oQiAN0Ukfma3jsGERnEk+4eP2JCyF Lj9HEjT4EumBTV+KICYB5lRuAjAYNsVXHLrOfpMjgIcSeZS8AgtI90RqJIbDfg6Z10 hFmayU4NLGA6uttJj250xPjwsklTp/S829OnWhlKDWNq6rOBRar8s/rhjpqax7jKMs vMir1Yi8mbLTiJnS9QrM8NTjY1ez1g/OdRuQpPgYj13PejDBf6ns54gxbfY2ciARPv RyTg13yMxw1YQ== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1vGnxu-000000019J6-0744; Wed, 05 Nov 2025 19:35:02 -0500 Message-ID: <20251106003501.890298562@kernel.org> User-Agent: quilt/0.68 Date: Wed, 05 Nov 2025 19:33:26 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [PATCH 2/2] tracing: Use switch statement instead of ifs in set_tracer_flag() References: <20251106003324.964761749@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Steven Rostedt The "mask" passed in to set_trace_flag() has a single bit set. The function then checks if the mask is equal to one of the option masks and performs the appropriate function associated to that option. Instead of having a bunch of "if ()" statement, use a "switch ()" statement instead to make it cleaner and a bit more optimal. No function changes. Signed-off-by: Steven Rostedt (Google) Reviewed-by: Masami Hiramatsu (Google) --- kernel/trace/trace.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 07bd10808277..8460bec9f263 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5251,11 +5251,13 @@ int trace_keep_overwrite(struct tracer *tracer, u64= mask, int set) =20 int set_tracer_flag(struct trace_array *tr, u64 mask, int enabled) { - if ((mask =3D=3D TRACE_ITER(RECORD_TGID)) || - (mask =3D=3D TRACE_ITER(RECORD_CMD)) || - (mask =3D=3D TRACE_ITER(TRACE_PRINTK)) || - (mask =3D=3D TRACE_ITER(COPY_MARKER))) + switch (mask) { + case TRACE_ITER(RECORD_TGID): + case TRACE_ITER(RECORD_CMD): + case TRACE_ITER(TRACE_PRINTK): + case TRACE_ITER(COPY_MARKER): lockdep_assert_held(&event_mutex); + } =20 /* do nothing if flag is already set */ if (!!(tr->trace_flags & mask) =3D=3D !!enabled) @@ -5266,7 +5268,8 @@ int set_tracer_flag(struct trace_array *tr, u64 mask,= int enabled) if (tr->current_trace->flag_changed(tr, mask, !!enabled)) return -EINVAL; =20 - if (mask =3D=3D TRACE_ITER(TRACE_PRINTK)) { + switch (mask) { + case TRACE_ITER(TRACE_PRINTK): if (enabled) { update_printk_trace(tr); } else { @@ -5283,9 +5286,9 @@ int set_tracer_flag(struct trace_array *tr, u64 mask,= int enabled) if (printk_trace =3D=3D tr) update_printk_trace(&global_trace); } - } + break; =20 - if (mask =3D=3D TRACE_ITER(COPY_MARKER)) { + case TRACE_ITER(COPY_MARKER): update_marker_trace(tr, enabled); /* update_marker_trace updates the tr->trace_flags */ return 0; @@ -5296,10 +5299,12 @@ int set_tracer_flag(struct trace_array *tr, u64 mas= k, int enabled) else tr->trace_flags &=3D ~mask; =20 - if (mask =3D=3D TRACE_ITER(RECORD_CMD)) + switch (mask) { + case TRACE_ITER(RECORD_CMD): trace_event_enable_cmd_record(enabled); + break; =20 - if (mask =3D=3D TRACE_ITER(RECORD_TGID)) { + case TRACE_ITER(RECORD_TGID): =20 if (trace_alloc_tgid_map() < 0) { tr->trace_flags &=3D ~TRACE_ITER(RECORD_TGID); @@ -5307,24 +5312,27 @@ int set_tracer_flag(struct trace_array *tr, u64 mas= k, int enabled) } =20 trace_event_enable_tgid_record(enabled); - } + break; =20 - if (mask =3D=3D TRACE_ITER(EVENT_FORK)) + case TRACE_ITER(EVENT_FORK): trace_event_follow_fork(tr, enabled); + break; =20 - if (mask =3D=3D TRACE_ITER(FUNC_FORK)) + case TRACE_ITER(FUNC_FORK): ftrace_pid_follow_fork(tr, enabled); + break; =20 - if (mask =3D=3D TRACE_ITER(OVERWRITE)) { + case TRACE_ITER(OVERWRITE): ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled); #ifdef CONFIG_TRACER_MAX_TRACE ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled); #endif - } + break; =20 - if (mask =3D=3D TRACE_ITER(PRINTK)) { + case TRACE_ITER(PRINTK): trace_printk_start_stop_comm(enabled); trace_printk_control(enabled); + break; } =20 return 0; --=20 2.51.0