From 42ce8d3b623162f3248db50a38359f294e6b06fd Mon Sep 17 00:00:00 2001
From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Thu, 30 Dec 2021 21:47:06 +0100
Subject: [PATCH] mt76: mt7615: fix a leftover race in runtime-pm
Git-commit: 42ce8d3b623162f3248db50a38359f294e6b06fd
Patch-mainline: v5.18-rc1
References: git-fixes
Fix a possible race in mt7615_pm_power_save_work() if rx/tx napi
schedules ps_work and we are currently accessing device register
on a different cpu.
Fixes: db928f1ab9789 ("mt76: mt7663: rely on mt76_connac_pm_ref/mt76_connac_pm_unref in tx/rx napi")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/wireless/mediatek/mt76/mt7615/mac.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index 2d81cbf2600c..bc72791cdcb5 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -2131,6 +2131,14 @@ void mt7615_pm_power_save_work(struct work_struct *work)
test_bit(MT76_HW_SCHED_SCANNING, &dev->mphy.state))
goto out;
+ if (mutex_is_locked(&dev->mt76.mutex))
+ /* if mt76 mutex is held we should not put the device
+ * to sleep since we are currently accessing device
+ * register map. We need to wait for the next power_save
+ * trigger.
+ */
+ goto out;
+
if (time_is_after_jiffies(dev->pm.last_activity + delta)) {
delta = dev->pm.last_activity + delta - jiffies;
goto out;
--
2.31.1