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From:   kah.jing.lee@intel.com
To:     Dinh Nguyen <dinguyen@kernel.org>
Cc:     linux-kernel@vger.kernel.org, tien.sung.ang@intel.com,
        Kah Jing Lee <kah.jing.lee@intel.com>
Subject: [PATCH] firmware: stratix10-rsu: prevent io block when sending RSU messages
Date:   Wed,  5 Jul 2023 10:18:47 +0800
Message-Id: <20230705021846.1536829-1-kah.jing.lee@intel.com>
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From: Kah Jing Lee <kah.jing.lee@intel.com>

Fix the issue for preventing recursive rsu mutex lock
issue in RSU update command.

Signed-off-by: Kah Jing Lee <kah.jing.lee@intel.com>
---
 drivers/firmware/stratix10-rsu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/stratix10-rsu.c b/drivers/firmware/stratix10-rsu.c
index e51c95f8d445..0a7542e9bb6f 100644
--- a/drivers/firmware/stratix10-rsu.c
+++ b/drivers/firmware/stratix10-rsu.c
@@ -280,7 +280,9 @@ static int rsu_send_msg(struct stratix10_rsu_priv *priv,
 	struct stratix10_svc_client_msg msg;
 	int ret;
 
-	mutex_lock(&priv->lock);
+	if (!mutex_trylock(&priv->lock))
+		return -EAGAIN;
+
 	reinit_completion(&priv->completion);
 	priv->client.receive_cb = callback;
 
@@ -525,7 +527,9 @@ static ssize_t reboot_image_store(struct device *dev,
 
 	ret = rsu_send_msg(priv, COMMAND_RSU_UPDATE,
 			   address, rsu_command_callback);
-	if (ret) {
+	if (ret == -EAGAIN)
+		return 0;
+	else if (ret) {
 		dev_err(dev, "Error, RSU update returned %i\n", ret);
 		return ret;
 	}
-- 
2.25.1