From:   Rob Clark <robdclark@gmail.com>
To:     dri-devel@lists.freedesktop.org
Cc:     Daniel Vetter <daniel@ffwll.ch>, freedreno@lists.freedesktop.org,
        linux-arm-msm@vger.kernel.org, Rob Clark <robdclark@chromium.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Pavel Machek <pavel@ucw.cz>, Len Brown <len.brown@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-pm@vger.kernel.org (open list:HIBERNATION (aka Software Suspend,
        aka swsusp)), linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v2 19/23] PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order
Date:   Mon, 20 Mar 2023 07:43:41 -0700
Message-Id: <20230320144356.803762-20-robdclark@gmail.com>
In-Reply-To: <20230320144356.803762-1-robdclark@gmail.com>
References: <20230320144356.803762-1-robdclark@gmail.com>
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From: Rob Clark <robdclark@chromium.org>

Annotate dev_pm_qos_mtx to teach lockdep to scream about allocations
that could trigger reclaim under dev_pm_qos_mtx.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/base/power/qos.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 9cba334b3729..d4addda3944a 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -1012,3 +1012,14 @@ void dev_pm_qos_hide_latency_tolerance(struct device *dev)
 	pm_runtime_put(dev);
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);
+
+static int __init dev_pm_qos_init(void)
+{
+	/* Teach lockdep about lock ordering wrt. shrinker: */
+	fs_reclaim_acquire(GFP_KERNEL);
+	might_lock(&dev_pm_qos_mtx);
+	fs_reclaim_release(GFP_KERNEL);
+
+	return 0;
+}
+early_initcall(dev_pm_qos_init);
-- 
2.39.2