CLEANUP: checks: remove return statements in locked functions
Given that all spinning loops we've had since 1.8-rc1 were caused by
unbalanced lock/unlock, let's get rid of all return statements in the
locked check functions and only exit via a a single unlock place.
diff --git a/src/checks.c b/src/checks.c
index 222704a..f669f8a 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -704,6 +704,9 @@
* the connection acknowledgement. If the proxy requires L7 health-checks,
* it sends the request. In other cases, it calls set_server_check_status()
* to set check->status, check->duration and check->result.
+ *
+ * Please do NOT place any return statement in this function and only leave
+ * via the out_unlock label.
*/
static void event_srv_chk_w(struct conn_stream *cs)
{
@@ -716,10 +719,8 @@
if (unlikely(check->result == CHK_RES_FAILED))
goto out_wakeup;
- if (conn->flags & CO_FL_HANDSHAKE) {
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return;
- }
+ if (conn->flags & CO_FL_HANDSHAKE)
+ goto out_unlock;
if (retrieve_errno_from_socket(conn)) {
chk_report_conn_err(check, errno, 0);
@@ -741,10 +742,8 @@
goto out_wakeup;
/* wake() will take care of calling tcpcheck_main() */
- if (check->type == PR_O2_TCPCHK_CHK) {
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return;
- }
+ if (check->type == PR_O2_TCPCHK_CHK)
+ goto out_unlock;
if (check->bo->o) {
conn->mux->snd_buf(cs, check->bo, 0);
@@ -753,10 +752,8 @@
__cs_stop_both(cs);
goto out_wakeup;
}
- if (check->bo->o) {
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return;
- }
+ if (check->bo->o)
+ goto out_unlock;
}
/* full request sent, we allow up to <timeout.check> if nonzero for a response */
@@ -769,8 +766,9 @@
out_wakeup:
task_wakeup(t, TASK_WOKEN_IO);
out_nowake:
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
__cs_stop_send(cs); /* nothing more to write */
+ out_unlock:
+ SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
}
/*
@@ -786,6 +784,9 @@
* distinguish between an SSL server and a pure TCP relay). All other cases will
* call it with a proper error status like HCHK_STATUS_L7STS, HCHK_STATUS_L6RSP,
* etc.
+ *
+ * Please do NOT place any return statement in this function and only leave
+ * via the out_unlock label.
*/
static void event_srv_chk_r(struct conn_stream *cs)
{
@@ -802,16 +803,12 @@
if (unlikely(check->result == CHK_RES_FAILED))
goto out_wakeup;
- if (conn->flags & CO_FL_HANDSHAKE) {
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return;
- }
+ if (conn->flags & CO_FL_HANDSHAKE)
+ goto out_unlock;
/* wake() will take care of calling tcpcheck_main() */
- if (check->type == PR_O2_TCPCHK_CHK) {
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return;
- }
+ if (check->type == PR_O2_TCPCHK_CHK)
+ goto out_unlock;
/* Warning! Linux returns EAGAIN on SO_ERROR if data are still available
* but the connection was closed on the remote end. Fortunately, recv still
@@ -1356,12 +1353,13 @@
conn->flags |= CO_FL_ERROR;
task_wakeup(t, TASK_WOKEN_IO);
+ out_unlock:
SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
return;
wait_more_data:
__cs_want_recv(cs);
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
+ goto out_unlock;
}
/*
@@ -1969,6 +1967,9 @@
/*
* manages a server health-check that uses an external process. Returns
* the time the task accepts to wait, or TIME_ETERNITY for infinity.
+ *
+ * Please do NOT place any return statement in this function and only leave
+ * via the out_unlock label.
*/
static struct task *process_chk_proc(struct task *t)
{
@@ -1981,10 +1982,8 @@
SPIN_LOCK(SERVER_LOCK, &check->server->lock);
if (!(check->state & CHK_ST_INPROGRESS)) {
/* no check currently running */
- if (!expired) { /* woke up too early */
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return t;
- }
+ if (!expired) /* woke up too early */
+ goto out_unlock;
/* we don't send any health-checks when the proxy is
* stopped, the server should not be checked or the check
@@ -2091,6 +2090,8 @@
reschedule:
while (tick_is_expired(t->expire, now_ms))
t->expire = tick_add(t->expire, MS_TO_TICKS(check->inter));
+
+ out_unlock:
SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
return t;
}
@@ -2098,6 +2099,9 @@
/*
* manages a server health-check that uses a connection. Returns
* the time the task accepts to wait, or TIME_ETERNITY for infinity.
+ *
+ * Please do NOT place any return statement in this function and only leave
+ * via the out_unlock label.
*/
static struct task *process_chk_conn(struct task *t)
{
@@ -2112,10 +2116,8 @@
SPIN_LOCK(SERVER_LOCK, &check->server->lock);
if (!(check->state & CHK_ST_INPROGRESS)) {
/* no check currently running */
- if (!expired) { /* woke up too early */
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return t;
- }
+ if (!expired) /* woke up too early */
+ goto out_unlock;
/* we don't send any health-checks when the proxy is
* stopped, the server should not be checked or the check
@@ -2140,8 +2142,8 @@
switch (ret) {
case SF_ERR_UP:
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return t;
+ goto out_unlock;
+
case SF_ERR_NONE:
/* we allow up to min(inter, timeout.connect) for a connection
* to establish but only when timeout.check is set
@@ -2219,7 +2221,7 @@
chk_report_conn_err(check, 0, expired);
}
else
- goto out_wait; /* timeout not reached, wait again */
+ goto out_unlock; /* timeout not reached, wait again */
}
/* check complete or aborted */
@@ -2265,7 +2267,7 @@
reschedule:
while (tick_is_expired(t->expire, now_ms))
t->expire = tick_add(t->expire, MS_TO_TICKS(check->inter));
- out_wait:
+ out_unlock:
SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
return t;
}
@@ -2579,6 +2581,9 @@
* both from the connection's wake() callback and from the check scheduling task.
* It returns 0 on normal cases, or <0 if a close() has happened on an existing
* connection, presenting the risk of an fd replacement.
+ *
+ * Please do NOT place any return statement in this function and only leave
+ * via the out_unlock label after setting retcode.
*/
static int tcpcheck_main(struct check *check)
{
@@ -2634,8 +2639,7 @@
if (s->proxy->timeout.check)
t->expire = tick_first(t->expire, t_con);
}
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return retcode;
+ goto out_unlock;
}
/* special case: option tcp-check with no rule, a connect is enough */
@@ -2730,8 +2734,7 @@
chunk_appendf(&trash, " comment: '%s'", comment);
set_server_check_status(check, HCHK_STATUS_SOCKERR, trash.str);
check->current_step = NULL;
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return retcode;
+ goto out_unlock;
}
if (check->cs)
@@ -2853,8 +2856,7 @@
if (s->proxy->timeout.check)
t->expire = tick_first(t->expire, t_con);
}
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return retcode;
+ goto out_unlock;
}
} /* end 'connect' */
@@ -3059,8 +3061,7 @@
if (&check->current_step->list != head &&
check->current_step->action == TCPCHK_ACT_EXPECT)
__cs_want_recv(cs);
- SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
- return retcode;
+ goto out_unlock;
out_end_tcpcheck:
/* collect possible new errors */
@@ -3074,6 +3075,8 @@
conn->flags |= CO_FL_ERROR;
__cs_stop_both(cs);
+
+ out_unlock:
SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
return retcode;
}