[PATCH v2] thermal: core: Use strnlen in thermal_zone_device_register_with_trips

[Thorsten Blum <thorsten.blum@linux.dev>]

Replace strlen() with the safer strnlen() and calculate the length of
the thermal zone name 'type' only once.  No functional changes.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
Changes in v2:
- Format the code differently (Rafael)
- Link to v1: https://lore.kernel.org/lkml/20251215121633.375193-1-thorsten.blum@linux.dev/
---
 drivers/thermal/thermal_core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 17ca5c082643..90e7edf16a52 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1505,15 +1505,19 @@ thermal_zone_device_register_with_trips(const char *type,
 	const struct thermal_trip *trip = trips;
 	struct thermal_zone_device *tz;
 	struct thermal_trip_desc *td;
+	size_t type_len = 0;
 	int id;
 	int result;
 
-	if (!type || strlen(type) == 0) {
+	if (type)
+		type_len = strnlen(type, THERMAL_NAME_LENGTH);
+
+	if (type_len == 0) {
 		pr_err("No thermal zone type defined\n");
 		return ERR_PTR(-EINVAL);
 	}
 
-	if (strlen(type) >= THERMAL_NAME_LENGTH) {
+	if (type_len == THERMAL_NAME_LENGTH) {
 		pr_err("Thermal zone name (%s) too long, should be under %d chars\n",
 		       type, THERMAL_NAME_LENGTH);
 		return ERR_PTR(-EINVAL);
-- 
Thorsten Blum <thorsten.blum@linux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4