[nginx] SSL: reworked posted next events again.

[Maxim Dounin]

details:   https://hg.nginx.org/nginx/rev/f1720934c45b
branches:  
changeset: 7617:f1720934c45b
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Fri Dec 27 19:43:01 2019 +0300
description:
SSL: reworked posted next events again.

Previous change 1ce3f01a4355 incorrectly introduced processing of the
ngx_posted_next_events queue at the end of operation, effectively making
posted next events a nop, since at the end of an event loop iteration
the queue is always empty.  Correct approach is to move events to the
ngx_posted_events queue at an iteration start, as it was done previously.

Further, in some cases the c->read event might be already in the
ngx_posted_events queue, and calling ngx_post_event() with the
ngx_posted_next_events queue won't do anything.  To make sure the event
will be correctly placed into the ngx_posted_next_events queue
we now check if it is already posted.

diffstat:

 src/event/ngx_event.c         |   2 +-
 src/event/ngx_event_openssl.c |   4 ++++
 src/event/ngx_event_posted.c  |  22 ++++++++++------------
 src/event/ngx_event_posted.h  |   2 +-
 4 files changed, 16 insertions(+), 14 deletions(-)

diffs (85 lines):

diff --git a/src/event/ngx_event.c b/src/event/ngx_event.c
--- a/src/event/ngx_event.c
+++ b/src/event/ngx_event.c
@@ -238,6 +238,7 @@ ngx_process_events_and_timers(ngx_cycle_
     }
 
     if (!ngx_queue_empty(&ngx_posted_next_events)) {
+        ngx_event_move_posted_next(cycle);
         timer = 0;
     }
 
@@ -261,7 +262,6 @@ ngx_process_events_and_timers(ngx_cycle_
     }
 
     ngx_event_process_posted(cycle, &ngx_posted_events);
-    ngx_event_process_posted_next(cycle, &ngx_posted_next_events);
 }
 
 
diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -2017,6 +2017,10 @@ ngx_ssl_recv(ngx_connection_t *c, u_char
                         c->read->available = 0;
                         c->read->ready = 0;
 
+                        if (c->read->posted) {
+                            ngx_delete_posted_event(c->read);
+                        }
+
                         ngx_post_event(c->read, &ngx_posted_next_events);
                     }
 
diff --git a/src/event/ngx_event_posted.c b/src/event/ngx_event_posted.c
--- a/src/event/ngx_event_posted.c
+++ b/src/event/ngx_event_posted.c
@@ -37,26 +37,24 @@ ngx_event_process_posted(ngx_cycle_t *cy
 
 
 void
-ngx_event_process_posted_next(ngx_cycle_t *cycle, ngx_queue_t *posted)
+ngx_event_move_posted_next(ngx_cycle_t *cycle)
 {
     ngx_queue_t  *q;
     ngx_event_t  *ev;
 
-    while (!ngx_queue_empty(posted)) {
-
-        q = ngx_queue_head(posted);
+    for (q = ngx_queue_head(&ngx_posted_next_events);
+         q != ngx_queue_sentinel(&ngx_posted_next_events);
+         q = ngx_queue_next(q))
+    {
         ev = ngx_queue_data(q, ngx_event_t, queue);
 
         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                       "posted next event %p", ev);
 
-        ngx_delete_posted_event(ev);
+        ev->ready = 1;
+        ev->available = -1;
+    }
 
-        if (!ev->ready) {
-            ev->ready = 1;
-            ev->available = -1;
-        }
-
-        ev->handler(ev);
-    }
+    ngx_queue_add(&ngx_posted_events, &ngx_posted_next_events);
+    ngx_queue_init(&ngx_posted_next_events);
 }
diff --git a/src/event/ngx_event_posted.h b/src/event/ngx_event_posted.h
--- a/src/event/ngx_event_posted.h
+++ b/src/event/ngx_event_posted.h
@@ -39,7 +39,7 @@
 
 
 void ngx_event_process_posted(ngx_cycle_t *cycle, ngx_queue_t *posted);
-void ngx_event_process_posted_next(ngx_cycle_t *cycle, ngx_queue_t *posted);
+void ngx_event_move_posted_next(ngx_cycle_t *cycle);
 
 
 extern ngx_queue_t  ngx_posted_accept_events;