From nobody Fri Dec 19 20:10:20 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 B51FD3043CD for ; Thu, 6 Nov 2025 21:03:58 +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=1762463038; cv=none; b=LNhqPZJuj2vE1BGQLAwFYoZOxbxRI2WxUyMz5ePkMYDOD6fmyDTwGSwXlbkM8DB/zkIxhcqrJjYhTwKJmRYMwsX0AEzIytaQMus2cOmvYXMs+UkN7W8mLB+2BRoHzPCQOJ3ABG7CsOI+bUzvONYaSuPzJIBM17Ygbx9tDrAsUbo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762463038; c=relaxed/simple; bh=WQdlEZLR91pyM/JJhDRZIhhFahmWBrTK9PMzbl3MwYU=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=NZyEZ1N78IFO3izmNaS4azpu0tm1aVOEe5KI2h9EhJTCx8k5KOWXFGxClHemJws2u7fO69FQilqS8fxa/SHyrSEzjLxeOhVyihADQvVFL2EG05qGW5DGXaBi6HJ3GPtTgcbxlcbjM3pYRnQgloW/bbpmrXgwiChHsP82U1+d2MQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E76R01OU; 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="E76R01OU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78E53C113D0; Thu, 6 Nov 2025 21:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762463038; bh=WQdlEZLR91pyM/JJhDRZIhhFahmWBrTK9PMzbl3MwYU=; h=Date:From:To:Cc:Subject:References:From; b=E76R01OUGuL+5mpBoODiYIyO30KnJH2q0n/cHWwhHpWcadHCSg/1vN7YU/tOKlX5q VcfJdf3YwO11rTUm7Z2aN2YCXPQY+WLUOxmHHPPYNfOvvxXHvIITMSPGB5sArJvhbi PodVB/mD1IVAjupEX5VXHto3whMITxomMne/wt3LNcc7q+8sO9y8VYkLTfgX27veTh rxdwUB3ki2hvNHamTgC+Crl8HJy/PpQ0E1CwtIFylIkVrLCodhAcv9dt37Zh6dDrvM NVcUaV+AYpmGdtJXQLk6SL+xuA73iiNiSgxXQM+a/inHP/Cbmf1wYAnNTuWYPRC8k8 u+zIht2spX+Aw== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1vH79C-000000008EI-0aa5; Thu, 06 Nov 2025 16:03:58 -0500 Message-ID: <20251106210357.996566505@kernel.org> User-Agent: quilt/0.68 Date: Thu, 06 Nov 2025 16:03:38 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [for-next][PATCH 7/7] tracing: Use switch statement instead of ifs in set_tracer_flag() References: <20251106210331.537317097@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. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Link: https://patch.msgid.link/20251106003501.890298562@kernel.org Signed-off-by: Steven Rostedt (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 88234b541b09..0aea9cb84276 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5220,11 +5220,13 @@ 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) @@ -5235,7 +5237,8 @@ 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 { @@ -5252,9 +5255,9 @@ 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; @@ -5265,10 +5268,12 @@ 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); @@ -5276,24 +5281,27 @@ 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