REORG: backend: simplify conn_backend_get
Reorganize the conditions for the reuse of idle/safe connections :
- reduce code by using variable to store reuse mode and idle/safe conns
counts
- consider that idle/safe/avail lists are properly allocated if
max_idle_conns not null. An allocation failure prevents haproxy
startup.
diff --git a/src/backend.c b/src/backend.c
index 51554fe..0d0447d 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1237,6 +1237,7 @@
struct connection *srv_conn = NULL;
struct conn_stream *srv_cs = NULL;
struct server *srv;
+ const int reuse_mode = s->be->options & PR_O_REUSE_MASK;
int reuse = 0;
int init_mux = 0;
int err;
@@ -1254,9 +1255,7 @@
srv = objt_server(s->target);
- if (srv && !reuse) {
- srv_conn = NULL;
-
+ if (srv && !reuse && reuse_mode != PR_O_REUSE_NEVR) {
/* Below we pick connections from the safe, idle or
* available (which are safe too) lists based
* on the strategy, the fact that this is a first or second
@@ -1275,31 +1274,29 @@
* Idle conns are necessarily looked up on the same thread so
* that there is no concurrency issues.
*/
- if (srv->available_conns && !LIST_ISEMPTY(&srv->available_conns[tid]) &&
- ((s->be->options & PR_O_REUSE_MASK) != PR_O_REUSE_NEVR)) {
+ if (!LIST_ISEMPTY(&srv->available_conns[tid])) {
srv_conn = LIST_ELEM(srv->available_conns[tid].n, struct connection *, list);
reuse = 1;
}
- else if (!srv_conn && srv->curr_idle_conns > 0) {
- if (srv->idle_conns && srv->safe_conns &&
- ((s->be->options & PR_O_REUSE_MASK) != PR_O_REUSE_NEVR &&
- s->txn && (s->txn->flags & TX_NOT_FIRST)) &&
- srv->curr_idle_nb + srv->curr_safe_nb > 0) {
- /* we're on the second column of the tables above, let's
- * try idle then safe.
- */
- srv_conn = conn_backend_get(s, srv, 0);
- }
- else if (srv->safe_conns &&
- ((s->txn && (s->txn->flags & TX_NOT_FIRST)) ||
- (s->be->options & PR_O_REUSE_MASK) >= PR_O_REUSE_AGGR) &&
- srv->curr_safe_nb > 0) {
- srv_conn = conn_backend_get(s, srv, 1);
+ /* if no available connections found, search for an idle/safe */
+ else if (srv->max_idle_conns && srv->curr_idle_conns > 0) {
+ const int not_first_req = s->txn && s->txn->flags & TX_NOT_FIRST;
+ const int idle = srv->curr_idle_nb > 0;
+ const int safe = srv->curr_safe_nb > 0;
+
+ /* second column of the tables above,
+ * search for an idle then safe conn */
+ if (not_first_req) {
+ if (idle || safe)
+ srv_conn = conn_backend_get(s, srv, 0);
}
- else if (srv->idle_conns &&
- ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_ALWS) &&
- srv->curr_idle_nb > 0) {
- srv_conn = conn_backend_get(s, srv, 0);
+ /* first column of the tables above */
+ else if (reuse_mode >= PR_O_REUSE_AGGR) {
+ /* search for a safe conn */
+ if (safe)
+ srv_conn = conn_backend_get(s, srv, 1);
+ else if (reuse_mode == PR_O_REUSE_ALWS && idle)
+ srv_conn = conn_backend_get(s, srv, 0);
}
if (srv_conn)
@@ -1401,7 +1398,7 @@
if (srv_conn) {
srv_conn->owner = s->sess;
- if ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_NEVR)
+ if (reuse_mode == PR_O_REUSE_NEVR)
conn_set_private(srv_conn);
}
}
@@ -1551,11 +1548,11 @@
* safe and the mux protocol supports multiplexing, add it in
* the session server list.
*/
- if (srv && ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_ALWS) &&
+ if (srv && reuse_mode == PR_O_REUSE_ALWS &&
!(srv_conn->flags & CO_FL_PRIVATE) && srv_conn->mux->avail_streams(srv_conn) > 0)
LIST_ADDQ(&srv->available_conns[tid], mt_list_to_list(&srv_conn->list));
else if (srv_conn->flags & CO_FL_PRIVATE ||
- ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_SAFE &&
+ (reuse_mode == PR_O_REUSE_SAFE &&
srv_conn->mux->flags & MX_FL_HOL_RISK)) {
/* If it fail now, the same will be done in mux->detach() callback */
session_add_conn(s->sess, srv_conn, srv_conn->target);