From: Carl Smith <carl.smith@alliedtelesis.co.nz>
Date: Tue, 12 Nov 2019 01:57:37 +0000 (+1300)
Subject: vcl: fix nonblocking accept with >1 event in the queue
X-Git-Tag: v19.08.2~70
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=c48306407b070760a95ad1dbb349845e07dd3231;p=vpp.git

vcl: fix nonblocking accept with >1 event in the queue

We discard unwanted events until we get an ACCEPTED.
But if we are non-blocking we need to check the queue
length every time and EAGAIN if empty before waiting.

Type: fix

Signed-off-by: Carl Smith <carl.smith@alliedtelesis.co.nz>
Change-Id: Ie0c7e5cb00f0d37d2e1534f8bb384221ff56f2e3
(cherry picked from commit 592a909a302262cf4088a5468b8e427f577725e8)
---

diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 349e27e5122..263fa916231 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -1464,11 +1464,11 @@ vppcom_session_accept (uint32_t listen_session_handle, vppcom_endpt_t * ep,
 
   is_nonblocking = VCL_SESS_ATTR_TEST (listen_session->attr,
 				       VCL_SESS_ATTR_NONBLOCK);
-  if (svm_msg_q_is_empty (wrk->app_event_queue) && is_nonblocking)
-    return VPPCOM_EAGAIN;
-
   while (1)
     {
+      if (svm_msg_q_is_empty (wrk->app_event_queue) && is_nonblocking)
+	return VPPCOM_EAGAIN;
+
       if (svm_msg_q_sub (wrk->app_event_queue, &msg, SVM_Q_WAIT, 0))
 	return VPPCOM_EAGAIN;