linux-kernel - [PATCH] platform/chrome: cros_ec_lpc: Sync filesystem on EC panic

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Message-ID: <20230726181738.1.Ic6b8e25120b2aec95e3d0f4ac92c2a35fc7a40e8@changeid>
Date:   Wed, 26 Jul 2023 18:17:39 +0000
From:   Rob Barnes <robbarnes@...gle.com>
To:     bleung@...omium.org, groeck@...omium.org, tzungbi@...nel.org,
        dtor@...omium.org
Cc:     Rob Barnes <robbarnes@...gle.com>, chrome-platform@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: [PATCH] platform/chrome: cros_ec_lpc: Sync filesystem on EC panic

Perform a filesystem sync when an EC panic is reported. The
sync is performed twice in case some inodes or pages are
temporarily locked. Testing showed syncing twice significantly
improved reliability.

hw_protection_shutdown is replaced for a couple reasons. It is
unnecessary because the EC will force reset either way.
hw_protection_shutdown does not reliably sync filesystem
before shutting down.

Signed-off-by: Rob Barnes <robbarnes@...gle.com>
---

 drivers/platform/chrome/cros_ec_lpc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 500a61b093e47..44b7637e745c2 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -327,8 +327,10 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
 		dev_emerg(ec_dev->dev, "CrOS EC Panic Reported. Shutdown is imminent!");
 		blocking_notifier_call_chain(&ec_dev->panic_notifier, 0, ec_dev);
 		kobject_uevent_env(&ec_dev->dev->kobj, KOBJ_CHANGE, (char **)env);
-		/* Begin orderly shutdown. Force shutdown after 1 second. */
-		hw_protection_shutdown("CrOS EC Panic", 1000);
+		/* Sync filesystem before EC resets */
+		ksys_sync_helper();
+		/* Sync again just in case some inodes were temporarily locked */
+		ksys_sync_helper();
 		/* Do not query for other events after a panic is reported */
 		return;
 	}
-- 
2.41.0.487.g6d72f3e995-goog