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

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

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170712155254.26455-1-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 552e71d5aa5fa9c6cff2d2ed232083977960512d..f7e292bf2baff049e852f3a73f0c5a6656c65a58 100644 (file)
--- 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