linux-kernel - [PATCH v3][next] tty: sunsu: Simplify device_node cleanup by using _

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Date: Sat, 18 May 2024 17:10:53 +0530
From: Shresth Prasad <shresthprasad7@...il.com>
To: davem@...emloft.net,
	gregkh@...uxfoundation.org,
	jirislaby@...nel.org
Cc: sparclinux@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org,
	Shresth Prasad <shresthprasad7@...il.com>,
	Julia Lawall <julia.lawall@...ia.fr>
Subject: [PATCH v3][next] tty: sunsu: Simplify device_node cleanup by using __free

Add `__free` function attribute to `ap` and `match` pointer
initialisations which ensure that the pointers are freed as soon as they
go out of scope, thus removing the need to manually free them using
`of_node_put`.

This also removes the need for the `goto` statement and the `rc`
variable.

Suggested-by: Julia Lawall <julia.lawall@...ia.fr>
Signed-off-by: Shresth Prasad <shresthprasad7@...il.com>
---
Changes in v3:
    - Remove incorrect testing statement

I've tested the patch by cross compiling it for sparc systems and
booting the produced `image` file in `qemu-system-sparc`.

---
 drivers/tty/serial/sunsu.c | 37 +++++++++++--------------------------
 1 file changed, 11 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/serial/sunsu.c b/drivers/tty/serial/sunsu.c
index 67a5fc70bb4b..0f463da5e7ce 100644
--- a/drivers/tty/serial/sunsu.c
+++ b/drivers/tty/serial/sunsu.c
@@ -1382,44 +1382,29 @@ static inline struct console *SUNSU_CONSOLE(void)
 
 static enum su_type su_get_type(struct device_node *dp)
 {
-	struct device_node *ap = of_find_node_by_path("/aliases");
-	enum su_type rc = SU_PORT_PORT;
+	struct device_node *ap __free(device_node) =
+			    of_find_node_by_path("/aliases");
 
 	if (ap) {
 		const char *keyb = of_get_property(ap, "keyboard", NULL);
 		const char *ms = of_get_property(ap, "mouse", NULL);
-		struct device_node *match;
 
 		if (keyb) {
-			match = of_find_node_by_path(keyb);
+			struct device_node *match __free(device_node) =
+					    of_find_node_by_path(keyb);
 
-			/*
-			 * The pointer is used as an identifier not
-			 * as a pointer, we can drop the refcount on
-			 * the of__node immediately after getting it.
-			 */
-			of_node_put(match);
-
-			if (dp == match) {
-				rc = SU_PORT_KBD;
-				goto out;
-			}
+			if (dp == match)
+				return SU_PORT_KBD;
 		}
 		if (ms) {
-			match = of_find_node_by_path(ms);
+			struct device_node *match __free(device_node) =
+					    of_find_node_by_path(ms);
 
-			of_node_put(match);
-
-			if (dp == match) {
-				rc = SU_PORT_MS;
-				goto out;
-			}
+			if (dp == match)
+				return SU_PORT_MS;
 		}
 	}
-
-out:
-	of_node_put(ap);
-	return rc;
+	return SU_PORT_PORT;
 }
 
 static int su_probe(struct platform_device *op)
-- 
2.44.0