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From: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
To: rafael@kernel.org, rui.zhang@intel.com,
	srinivas.pandruvada@linux.intel.com, daniel.lezcano@linaro.org
Cc: linux-pm@vger.kernel.org,
	Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Subject: [PATCH v2] thermal: Use symbolic constant for UUID prefix comparison
Date: Thu, 30 Oct 2025 09:29:55 +0530	[thread overview]
Message-ID: <20251030035955.62171-1-kaushlendra.kumar@intel.com> (raw)

Replace sizeof() with a symbolic constant for UUID matching to maintain
existing ABI behavior while improving code clarity. The current behavior
of comparing only the first 7 characters is sufficient to distinguish
all UUIDs and changing to full string comparison would alter the kernel
ABI, potentially breaking existing userspace applications.

Use a defined constant to make the truncated comparison explicit and
maintainable.

Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
---
Changes in v2:
- Use symbolic constant instead of strlen() to maintain existing ABI
  behavior as review feedback

 drivers/thermal/intel/int340x_thermal/int3400_thermal.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/intel/int340x_thermal/int3400_thermal.c b/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
index 908cc1bf57f1..128556632685 100644
--- a/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
+++ b/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
@@ -16,6 +16,8 @@
 #define INT3400_ODVP_CHANGED 0x88
 #define INT3400_KEEP_ALIVE 0xA0
 #define INT3400_FAKE_TEMP (20 * 1000) /* faked temp sensor with 20C */
+/* UUID prefix length for comparison - sufficient for all UUIDs */
+#define INT3400_UUID_PREFIX_LEN 7
 
 enum int3400_thermal_uuid {
 	INT3400_THERMAL_ACTIVE = 0,
@@ -199,7 +201,7 @@ static ssize_t current_uuid_store(struct device *dev,
 
 	for (i = 0; i < INT3400_THERMAL_MAXIMUM_UUID; ++i) {
 		if (!strncmp(buf, int3400_thermal_uuids[i],
-			     sizeof(int3400_thermal_uuids[i]) - 1)) {
+			     INT3400_UUID_PREFIX_LEN)) {
 			/*
 			 * If we have a list of supported UUIDs, make sure
 			 * this one is supported.
-- 
2.34.1


             reply	other threads:[~2025-10-30  4:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-30  3:59 Kaushlendra Kumar [this message]
2025-11-12 20:07 ` [PATCH v2] thermal: Use symbolic constant for UUID prefix comparison Rafael J. Wysocki

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