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Message-Id: <20230704-thinkpad_acpi-lockdep-v1-2-60129548a738@weissschuh.net>
Date: Tue, 04 Jul 2023 23:03:18 +0200
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Henrique de Moraes Holschuh <hmh@....eng.br>,
Hans de Goede <hdegoede@...hat.com>,
Mark Gross <markgross@...nel.org>
Cc: ibm-acpi-devel@...ts.sourceforge.net,
platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH 2/2] platform/x86: thinkpad_acpi: use lockdep annotations
Instead of relying on free-form comments to document locking
requirements use well-known lockdep annotations.
These can also be validated at runtime make sure the invariants are not
violated.
Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
drivers/platform/x86/thinkpad_acpi.c | 41 +++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 17 deletions(-)
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index b796e65c99e0..25cc86a4a36a 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -50,6 +50,7 @@
#include <linux/kthread.h>
#include <linux/leds.h>
#include <linux/list.h>
+#include <linux/lockdep.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nvram.h>
@@ -2071,11 +2072,11 @@ static int hotkey_get_tablet_mode(int *status)
* hotkey_acpi_mask accordingly. Also resets any bits
* from hotkey_user_mask that are unavailable to be
* delivered (shadow requirement of the userspace ABI).
- *
- * Call with hotkey_mutex held
*/
static int hotkey_mask_get(void)
{
+ lockdep_assert_held(&hotkey_mutex);
+
if (tp_features.hotkey_mask) {
u32 m = 0;
@@ -2111,8 +2112,6 @@ static void hotkey_mask_warn_incomplete_mask(void)
* Also calls hotkey_mask_get to update hotkey_acpi_mask.
*
* NOTE: does not set bits in hotkey_user_mask, but may reset them.
- *
- * Call with hotkey_mutex held
*/
static int hotkey_mask_set(u32 mask)
{
@@ -2121,6 +2120,8 @@ static int hotkey_mask_set(u32 mask)
const u32 fwmask = mask & ~hotkey_source_mask;
+ lockdep_assert_held(&hotkey_mutex);
+
if (tp_features.hotkey_mask) {
for (i = 0; i < 32; i++) {
if (!acpi_evalf(hkey_handle,
@@ -2152,13 +2153,13 @@ static int hotkey_mask_set(u32 mask)
/*
* Sets hotkey_user_mask and tries to set the firmware mask
- *
- * Call with hotkey_mutex held
*/
static int hotkey_user_mask_set(const u32 mask)
{
int rc;
+ lockdep_assert_held(&hotkey_mutex);
+
/* Give people a chance to notice they are doing something that
* is bound to go boom on their users sooner or later */
if (!tp_warned.hotkey_mask_ff &&
@@ -2519,21 +2520,23 @@ static int hotkey_kthread(void *data)
return 0;
}
-/* call with hotkey_mutex held */
static void hotkey_poll_stop_sync(void)
{
+ lockdep_assert_held(&hotkey_mutex);
+
if (tpacpi_hotkey_task) {
kthread_stop(tpacpi_hotkey_task);
tpacpi_hotkey_task = NULL;
}
}
-/* call with hotkey_mutex held */
static void hotkey_poll_setup(const bool may_warn)
{
const u32 poll_driver_mask = hotkey_driver_mask & hotkey_source_mask;
const u32 poll_user_mask = hotkey_user_mask & hotkey_source_mask;
+ lockdep_assert_held(&hotkey_mutex);
+
if (hotkey_poll_freq > 0 &&
(poll_driver_mask ||
(poll_user_mask && tpacpi_inputdev->users > 0))) {
@@ -2562,9 +2565,10 @@ static void hotkey_poll_setup_safe(const bool may_warn)
mutex_unlock(&hotkey_mutex);
}
-/* call with hotkey_mutex held */
static void hotkey_poll_set_freq(unsigned int freq)
{
+ lockdep_assert_held(&hotkey_mutex);
+
if (!freq)
hotkey_poll_stop_sync();
@@ -6664,12 +6668,13 @@ static unsigned int brightness_enable = 2; /* 2 = auto, 0 = no, 1 = yes */
static struct mutex brightness_mutex;
-/* NVRAM brightness access,
- * call with brightness_mutex held! */
+/* NVRAM brightness access */
static unsigned int tpacpi_brightness_nvram_get(void)
{
u8 lnvram;
+ lockdep_assert_held(&brightness_mutex);
+
lnvram = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
& TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
>> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
@@ -6717,11 +6722,12 @@ static void tpacpi_brightness_checkpoint_nvram(void)
}
-/* call with brightness_mutex held! */
static int tpacpi_brightness_get_raw(int *status)
{
u8 lec = 0;
+ lockdep_assert_held(&brightness_mutex);
+
switch (brightness_mode) {
case TPACPI_BRGHT_MODE_UCMS_STEP:
*status = tpacpi_brightness_nvram_get();
@@ -6737,12 +6743,13 @@ static int tpacpi_brightness_get_raw(int *status)
}
}
-/* call with brightness_mutex held! */
/* do NOT call with illegal backlight level value */
static int tpacpi_brightness_set_ec(unsigned int value)
{
u8 lec = 0;
+ lockdep_assert_held(&brightness_mutex);
+
if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
return -EIO;
@@ -6754,12 +6761,13 @@ static int tpacpi_brightness_set_ec(unsigned int value)
return 0;
}
-/* call with brightness_mutex held! */
static int tpacpi_brightness_set_ucmsstep(unsigned int value)
{
int cmos_cmd, inc;
unsigned int current_value, i;
+ lockdep_assert_held(&brightness_mutex);
+
current_value = tpacpi_brightness_nvram_get();
if (value == current_value)
@@ -8208,11 +8216,10 @@ static bool fan_select_fan2(void)
return true;
}
-/*
- * Call with fan_mutex held
- */
static void fan_update_desired_level(u8 status)
{
+ lockdep_assert_held(&fan_mutex);
+
if ((status &
(TP_EC_FAN_AUTO | TP_EC_FAN_FULLSPEED)) == 0) {
if (status > 7)
--
2.41.0
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