linux-kernel - [PATCH v3 1/2] PM: narrow down -DDEBUG on kernel/power/ files

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Date:   Thu, 24 Mar 2022 08:07:24 +0000
From:   David Cohen <dacohen@...me>
To:     rafael@...nel.org, len.brown@...el.com, pavel@....cz
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        David Cohen <dacohen@...me>
Subject: [PATCH v3 1/2] PM: narrow down -DDEBUG on kernel/power/ files

The macro -DDEBUG is broadly enabled on kernel/power/ directory if
CONFIG_DYNAMIC_DEBUG is enabled. As side effect all debug messages using
pr_debug() and dev_dbg() are enabled by default on dynamic debug.
We're reworking pm_pr_dbg() to support dynamic debug, where pm_pr_dbg()
will print message if either pm_debug_messages_on flag is set or if it's
explicitly enabled on dynamic debug's control. That means if we let
-DDEBUG broadly set, the pm_debug_messages_on flag will be bypassed by
default on pm_pr_dbg() if dynamic debug is also enabled.

The files that directly use pr_debug() and dev_dbg() on kernel/power/ are:
 - swap.c
 - snapshot.c
 - energy_model.c

And those files do not use pm_pr_dbg(). So if we limit -DDEBUG to them,
we keep the same functional behavior while allowing the pm_pr_dbg()
refactor.

Signed-off-by: David Cohen <dacohen@...me>
---
 kernel/power/Makefile  | 6 +++++-
 kernel/power/process.c | 3 ---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 5899260a8bef..874ad834dc8d 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -1,6 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0

-ccflags-$(CONFIG_PM_DEBUG)	:= -DDEBUG
+ifeq ($(CONFIG_DYNAMIC_DEBUG), y)
+CFLAGS_swap.o                   := -DDEBUG
+CFLAGS_snapshot.o               := -DDEBUG
+CFLAGS_energy_model.o           := -DDEBUG
+endif

 KASAN_SANITIZE_snapshot.o	:= n

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 11b570fcf049..3068601e585a 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -6,9 +6,6 @@
  * Originally from swsusp.
  */

-
-#undef DEBUG
-
 #include <linux/interrupt.h>
 #include <linux/oom.h>
 #include <linux/suspend.h>
--
2.35.1