[PATCH] sysrq: Auto release device node using __free attribute

Roman Storozhenko
2024-04-11T18:03:02Z

Add a cleanup function attribute '__free(device_node)' to the device node
pointer initialization statement and remove the pairing cleanup function
call of 'of_node_put' at the end of the function.
The '_free()' attrubute is introduced by scope-based resource management
in-kernel framework implemented in 'cleanup.h'. A pointer marked with
'__free()' attribute makes a compiler insert a cleanup function call
to the places where the pointer goes out of the scope. This feature
allows to get rid of manual cleanup function calls.

Suggested-by: Julia.Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Roman Storozhenko <romeusmeister@gmail.com>
---
This patch targets the next tree:
tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
tag: next-20240411
---
drivers/tty/sysrq.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 02217e3c916b..1d1261f618c0 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -758,11 +758,12 @@ static void sysrq_detect_reset_sequence(struct sysrq_state *state,
static void sysrq_of_get_keyreset_config(void)
{
u32 key;
- struct device_node *np;
struct property *prop;
const __be32 *p;

- np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq");
+ struct device_node *np __free(device_node) =
+ of_find_node_by_path("/chosen/linux,sysrq-reset-seq");
+
if (!np) {
pr_debug("No sysrq node found");
return;
@@ -781,8 +782,6 @@ static void sysrq_of_get_keyreset_config(void)

/* Get reset timeout if any. */
of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms);
-
- of_node_put(np);
}
#else
static void sysrq_of_get_keyreset_config(void)
--
2.34.1