greybus: fix a timeout race
Whenever we send a request message we start a timer to ensure the
we don't wait too long for the matching response to arrive.
Currently we set up the timeout *after* sending the message, but
that is subject to a race--the response could arrive (and the
timeout prematurely disabled) before the timeout is even set up.
Set up the timeout before sending the message.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
index e647425..3e3fc73 100644
--- a/drivers/staging/greybus/operation.c
+++ b/drivers/staging/greybus/operation.c
@@ -447,13 +447,20 @@
*/
operation->callback = callback;
gb_pending_operation_insert(operation);
+
+ /*
+ * We impose a time limit for requests to complete. We need
+ * to set the timer before we send the request though, so we
+ * don't lose a race with the receipt of the resposne.
+ */
+ timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT);
+ schedule_delayed_work(&operation->timeout_work, timeout);
+
+ /* All set, send the request */
ret = gb_message_send(&operation->request, GFP_KERNEL);
if (ret)
return ret;
- /* We impose a time limit for requests to complete. */
- timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT);
- schedule_delayed_work(&operation->timeout_work, timeout);
if (!callback)
ret = gb_operation_wait(operation);