[PATCH] drm/dp/mst: Use memchr_inv() instead of memcmp() against a zeroed array

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

We have memch_inv(), so no need to memcmp() against a zeroed temp array.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 552e71d5aa5f..f7e292bf2baf 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1337,15 +1337,17 @@ static void drm_dp_mst_link_probe_work(struct work_struct *work)
 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
 				 u8 *guid)
 {
-	static u8 zero_guid[16];
+	u64 salt;
 
-	if (!memcmp(guid, zero_guid, 16)) {
-		u64 salt = get_jiffies_64();
-		memcpy(&guid[0], &salt, sizeof(u64));
-		memcpy(&guid[8], &salt, sizeof(u64));
-		return false;
-	}
-	return true;
+	if (memchr_inv(guid, 0, 16))
+		return true;
+
+	salt = get_jiffies_64();
+
+	memcpy(&guid[0], &salt, sizeof(u64));
+	memcpy(&guid[8], &salt, sizeof(u64));
+
+	return false;
 }
 
 #if 0
-- 
2.13.0