linux-kernel - [PATCH 5.15 802/917] ACPI: PM: Fix device wakeup power reference counting error

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Message-Id: <20211115165456.170065434@linuxfoundation.org>
Date:   Mon, 15 Nov 2021 18:04:57 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 802/917] ACPI: PM: Fix device wakeup power reference counting error

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

[ Upstream commit 452a3e723f75880757acf87b053935c43aa89f89 ]

Fix a device wakeup power reference counting error introduced by
commit a2d7b2e004af ("ACPI: PM: Fix sharing of wakeup power
resources") because of a coding mistake.

Fixes: a2d7b2e004af ("ACPI: PM: Fix sharing of wakeup power resources")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/acpi/power.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 4b42debeed455..c95eedd58f5bf 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -755,13 +755,11 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 
 	mutex_lock(&acpi_device_lock);
 
-	if (dev->wakeup.prepare_count > 1) {
-		dev->wakeup.prepare_count--;
+	/* Do nothing if wakeup power has not been enabled for this device. */
+	if (dev->wakeup.prepare_count <= 0)
 		goto out;
-	}
 
-	/* Do nothing if wakeup power has not been enabled for this device. */
-	if (!dev->wakeup.prepare_count)
+	if (--dev->wakeup.prepare_count > 0)
 		goto out;
 
 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
-- 
2.33.0