Merge tag 'tpmdd-next-20200108' of git://git.infradead.org/users/jjs/linux-tpmdd

Pull more tpmd fixes from Jarkko Sakkinen:
 "One critical regression fix (the faulty commit got merged in rc3, but
  also marked for stable)"

* tag 'tpmdd-next-20200108' of git://git.infradead.org/users/jjs/linux-tpmdd:
  tpm: Handle negative priv->response_len in tpm_common_read()

drivers/char/tpm/tpm-dev-common.c

@@ -130,7 +130,7 @@ ssize_t tpm_common_read(struct file *file, char __user *buf,
 		priv->response_read = true;
 
 		ret_size = min_t(ssize_t, size, priv->response_length);
-		if (!ret_size) {
+		if (ret_size <= 0) {
 			priv->response_length = 0;
 			goto out;
 		}

drivers/char/tpm/tpm-dev.h

@@ -14,7 +14,7 @@ struct file_priv {
 	struct work_struct timeout_work;
 	struct work_struct async_work;
 	wait_queue_head_t async_wait;
-	size_t response_length;
+	ssize_t response_length;
 	bool response_read;
 	bool command_enqueued;