linux-kernel - [PATCH v2 2/2] power: supply: samsung-sdi-battery: Constify struct power_supply_maintenance_charge

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Message-ID: <6caafd0ac2556a40405273b1a4badc508ea8e9b0.1719125040.git.christophe.jaillet@wanadoo.fr>
Date: Sun, 23 Jun 2024 10:04:45 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: linus.walleij@...aro.org,
	Sebastian Reichel <sre@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	linux-pm@...r.kernel.org
Subject: [PATCH v2 2/2] power: supply: samsung-sdi-battery: Constify struct power_supply_maintenance_charge_table

'struct power_supply_maintenance_charge_table' is not modified in this
driver.

Constifying this structure moves some data to a read-only section, so
increase overall security.

In order to do it, some code also needs to be adjusted to this new const
qualifier.

On a x86_64, with allmodconfig:
Before:
======
$ size drivers/power/supply/samsung-sdi-battery.o
   text	   data	    bss	    dec	    hex	filename
   4055	   4584	      0	   8639	   21bf	drivers/power/supply/samsung-sdi-battery.o

After:
=====
$ size drivers/power/supply/samsung-sdi-battery.o
   text	   data	    bss	    dec	    hex	filename
   4087	   4552	      0	   8639	   21bf	drivers/power/supply/samsung-sdi-battery.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
Compile tested-only

Changes in v2
  - Add Linus Walleij <linus.walleij@...aro.org> in Cc  [Sebastian Reichel]
  - Also update ab8500_chargalg.c  [Sebastian Reichel, kernel test robot]

v1: https://lore.kernel.org/all/02c6ad69a3ace192c9d609b7336a681a8fc7ba94.1717253900.git.christophe.jaillet@wanadoo.fr/
---
 drivers/power/supply/ab8500_chargalg.c     | 2 +-
 drivers/power/supply/power_supply_core.c   | 2 +-
 drivers/power/supply/samsung-sdi-battery.c | 2 +-
 include/linux/power_supply.h               | 6 +++---
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/power/supply/ab8500_chargalg.c b/drivers/power/supply/ab8500_chargalg.c
index 55ab7a28056e..854491ad3ecd 100644
--- a/drivers/power/supply/ab8500_chargalg.c
+++ b/drivers/power/supply/ab8500_chargalg.c
@@ -1225,8 +1225,8 @@ static bool ab8500_chargalg_time_to_restart(struct ab8500_chargalg *di)
  */
 static void ab8500_chargalg_algorithm(struct ab8500_chargalg *di)
 {
+	const struct power_supply_maintenance_charge_table *mt;
 	struct power_supply_battery_info *bi = di->bm->bi;
-	struct power_supply_maintenance_charge_table *mt;
 	int charger_status;
 	int ret;
 
diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index 022d0e4bf621..8f6025acd10a 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -1072,7 +1072,7 @@ int power_supply_vbat2ri(struct power_supply_battery_info *info,
 }
 EXPORT_SYMBOL_GPL(power_supply_vbat2ri);
 
-struct power_supply_maintenance_charge_table *
+const struct power_supply_maintenance_charge_table *
 power_supply_get_maintenance_charging_setting(struct power_supply_battery_info *info,
 					      int index)
 {
diff --git a/drivers/power/supply/samsung-sdi-battery.c b/drivers/power/supply/samsung-sdi-battery.c
index 725fbe09379e..b63fd2758c2f 100644
--- a/drivers/power/supply/samsung-sdi-battery.c
+++ b/drivers/power/supply/samsung-sdi-battery.c
@@ -613,7 +613,7 @@ static struct power_supply_battery_ocv_table samsung_ocv_cap_eb585157lu[] = {
 	{ .ocv = 3300000, .capacity = 0},
 };
 
-static struct power_supply_maintenance_charge_table samsung_maint_charge_table[] = {
+static const struct power_supply_maintenance_charge_table samsung_maint_charge_table[] = {
 	{
 		/* Maintenance charging phase A, 60 hours */
 		.charge_current_max_ua = 600000,
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 5061eeecf62e..72dc7e45c90c 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -736,7 +736,7 @@ struct power_supply_battery_info {
 	int overvoltage_limit_uv;
 	int constant_charge_current_max_ua;
 	int constant_charge_voltage_max_uv;
-	struct power_supply_maintenance_charge_table *maintenance_charge;
+	const struct power_supply_maintenance_charge_table *maintenance_charge;
 	int maintenance_charge_size;
 	int alert_low_temp_charge_current_ua;
 	int alert_low_temp_charge_voltage_uv;
@@ -810,7 +810,7 @@ power_supply_temp2resist_simple(struct power_supply_resistance_temp_table *table
 				int table_len, int temp);
 extern int power_supply_vbat2ri(struct power_supply_battery_info *info,
 				int vbat_uv, bool charging);
-extern struct power_supply_maintenance_charge_table *
+extern const struct power_supply_maintenance_charge_table *
 power_supply_get_maintenance_charging_setting(struct power_supply_battery_info *info, int index);
 extern bool power_supply_battery_bti_in_range(struct power_supply_battery_info *info,
 					      int resistance);
@@ -824,7 +824,7 @@ extern int power_supply_set_battery_charged(struct power_supply *psy);
 static inline bool
 power_supply_supports_maintenance_charging(struct power_supply_battery_info *info)
 {
-	struct power_supply_maintenance_charge_table *mt;
+	const struct power_supply_maintenance_charge_table *mt;
 
 	mt = power_supply_get_maintenance_charging_setting(info, 0);
 
-- 
2.45.2