Revert "MEDIUM: queue: make pendconn_process_next_strm() only return the pendconn"
This reverts commit 5304669e1b1a213d2754755a47735ecd5549ce7b.
The recent changes since 5304669e1 MEDIUM: queue: make
pendconn_process_next_strm() only return the pendconn opened a tiny race
condition between stream_free() and process_srv_queue(), as the pendconn
is accessed outside of the lock, possibly while it's being freed. A
different approach is required.
diff --git a/src/queue.c b/src/queue.c
index 60b16a0..84d197d 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -254,14 +254,11 @@
* to <srv>.
*
* This function must only be called if the server queue _AND_ the proxy queue
- * are locked. Today it is only called by process_srv_queue.
- *
- * The function returns the dequeued pendconn on success or NULL if none is
- * available. It's up to the caller to add the corresponding stream to the
- * server's list, to update the LB algo, update ->served, and to wake up the
- * stream's task.
+ * are locked. Today it is only called by process_srv_queue. When a pending
+ * connection is dequeued, this function returns 1 if the pending connection can
+ * be handled by the current thread, else it returns 2.
*/
-static struct pendconn *pendconn_process_next_strm(struct server *srv, struct proxy *px)
+static int pendconn_process_next_strm(struct server *srv, struct proxy *px)
{
struct pendconn *p = NULL;
struct pendconn *pp = NULL;
@@ -284,7 +281,7 @@
pp = pendconn_first(&px->queue.head);
if (!p && !pp)
- return NULL;
+ return 0;
else if (!pp)
goto use_p; /* p != NULL */
else if (!p)
@@ -326,8 +323,17 @@
unlinked:
p->strm_flags |= SF_ASSIGNED;
p->target = srv;
+
+ _HA_ATOMIC_INC(&srv->served);
+ _HA_ATOMIC_INC(&srv->proxy->served);
__ha_barrier_atomic_store();
- return p;
+ if (px->lbprm.server_take_conn)
+ px->lbprm.server_take_conn(srv);
+ stream_add_srv_conn(p->strm, srv);
+
+ task_wakeup(p->strm->task, TASK_WOKEN_RES);
+
+ return 1;
}
/* Manages a server's connection queue. This function will try to dequeue as
@@ -337,7 +343,6 @@
void process_srv_queue(struct server *s, int server_locked)
{
struct proxy *p = s->proxy;
- int done = 0;
int maxconn;
if (!server_locked)
@@ -345,26 +350,13 @@
HA_RWLOCK_WRLOCK(PROXY_LOCK, &p->lock);
maxconn = srv_dynamic_maxconn(s);
while (s->served < maxconn) {
- struct pendconn *pc;
-
- pc = pendconn_process_next_strm(s, p);
- if (!pc)
+ int ret = pendconn_process_next_strm(s, p);
+ if (!ret)
break;
-
- done = 1;
-
- _HA_ATOMIC_INC(&s->served);
- _HA_ATOMIC_INC(&p->served);
-
- stream_add_srv_conn(pc->strm, s);
- task_wakeup(pc->strm->task, TASK_WOKEN_RES);
}
HA_RWLOCK_WRUNLOCK(PROXY_LOCK, &p->lock);
if (!server_locked)
HA_SPIN_UNLOCK(SERVER_LOCK, &s->lock);
-
- if (done && p->lbprm.server_take_conn)
- p->lbprm.server_take_conn(s);
}
/* Adds the stream <strm> to the pending connection queue of server <strm>->srv