* the module usage count.
  */
 #define TPM_ORD_PCR_EXTEND cpu_to_be32(20)
-#define EXTEND_PCR_SIZE 34
+#define EXTEND_PCR_RESULT_SIZE 34
 static struct tpm_input_header pcrextend_header = {
        .tag = TPM_TAG_RQU_COMMAND,
        .length = cpu_to_be32(34),
                return -ENODEV;
 
        cmd.header.in = pcrextend_header;
-       BUILD_BUG_ON(be32_to_cpu(cmd.header.in.length) > EXTEND_PCR_SIZE);
        cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
        memcpy(cmd.params.pcrextend_in.hash, hash, TPM_DIGEST_SIZE);
-       rc = transmit_cmd(chip, &cmd, cmd.header.in.length,
+       rc = transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
                          "attempting extend a PCR value");
 
        module_put(chip->dev->driver->owner);