linux-kernel - [PATCH v2] firmware: Hold a reference for of_find_compatible

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Date:   Tue, 28 Jun 2022 10:16:40 +0800
From:   Liang He <windhl@....com>
To:     broonie@...nel.org, gregkh@...uxfoundation.org,
        ckeepax@...nsource.cirrus.com, michal.simek@...inx.com,
        abhyuday.godhasara@...inx.com, simont@...nsource.cirrus.com,
        ronak.jain@...inx.com, peng.fan@....com,
        linux-kernel@...r.kernel.org
Cc:     windhl@....com
Subject: [PATCH v2] firmware: Hold a reference for of_find_compatible_node()

In of_register_trusted_foundations(), we need to hold the reference
returned by of_find_compatible_node() and then use it to call
of_node_put() for refcount balance.

Signed-off-by: Liang He <windhl@....com>
---
 v2: use 'check-and-put' coding style
 v1: hold ref returned by of_find_xxx
 
 v1 link: https://lore.kernel.org/all/20220621032625.4078445-1-windhl@126.com/



 include/linux/firmware/trusted_foundations.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/linux/firmware/trusted_foundations.h b/include/linux/firmware/trusted_foundations.h
index be5984bda592..931b6c5c72df 100644
--- a/include/linux/firmware/trusted_foundations.h
+++ b/include/linux/firmware/trusted_foundations.h
@@ -71,12 +71,16 @@ static inline void register_trusted_foundations(
 
 static inline void of_register_trusted_foundations(void)
 {
+	struct device_node *np = of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations");
+
+	if (!np)
+		return;
+	of_node_put(np);
 	/*
 	 * If we find the target should enable TF but does not support it,
 	 * fail as the system won't be able to do much anyway
 	 */
-	if (of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations"))
-		register_trusted_foundations(NULL);
+	register_trusted_foundations(NULL);
 }
 
 static inline bool trusted_foundations_registered(void)
-- 
2.25.1