diff --git a/modules/ngx_http_upstream_iwrr_module/ngx_http_upstream_iwrr_module.c b/modules/ngx_http_upstream_iwrr_module/ngx_http_upstream_iwrr_module.c
index 13caf6ff23..e8848bcf40 100644
--- a/modules/ngx_http_upstream_iwrr_module/ngx_http_upstream_iwrr_module.c
+++ b/modules/ngx_http_upstream_iwrr_module/ngx_http_upstream_iwrr_module.c
@@ -46,7 +46,7 @@ static ngx_int_t ngx_http_upstream_init_iwrr_peer(ngx_http_request_t *r,
 static ngx_int_t ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc,
     void *data);
 static ngx_http_upstream_rr_peer_t *ngx_http_upstream_get_iwrr(
-    ngx_http_upstream_iwrr_peer_data_t *oip);
+    ngx_http_upstream_iwrr_peer_data_t *uip);
 static ngx_http_upstream_iwrr_queue_t *ngx_http_upstream_iwrr_queue_next(
     ngx_http_upstream_iwrr_srv_conf_t *uiscf);
 
@@ -229,20 +229,20 @@ ngx_http_upstream_init_iwrr_peer(ngx_http_request_t *r,
     ngx_http_upstream_srv_conf_t *us)
 {
     ngx_http_upstream_iwrr_srv_conf_t     *uiscf;
-    ngx_http_upstream_iwrr_peer_data_t    *oip;
+    ngx_http_upstream_iwrr_peer_data_t    *uip;
 
     uiscf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_iwrr_module);
     if (uiscf == NULL) {
         return NGX_ERROR;
     }
 
-    oip = ngx_palloc(r->pool, sizeof(ngx_http_upstream_iwrr_peer_data_t));
-    if (oip == NULL) {
+    uip = ngx_palloc(r->pool, sizeof(ngx_http_upstream_iwrr_peer_data_t));
+    if (uip == NULL) {
         return NGX_ERROR;
     }
 
-    oip->uiscf = uiscf;
-    r->upstream->peer.data = &oip->rrp;
+    uip->uiscf = uiscf;
+    r->upstream->peer.data = &uip->rrp;
 
     if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
         return NGX_ERROR;
@@ -256,7 +256,7 @@ ngx_http_upstream_init_iwrr_peer(ngx_http_request_t *r,
 static ngx_int_t
 ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc, void *data)
 {
-    ngx_http_upstream_iwrr_peer_data_t    *oip = data;
+    ngx_http_upstream_iwrr_peer_data_t    *uip = data;
 
     ngx_int_t                                rc;
     ngx_uint_t                               i, n;
@@ -270,7 +270,7 @@ ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc, void *data)
     pc->cached = 0;
     pc->connection = NULL;
 
-    rrp = &oip->rrp;
+    rrp = &uip->rrp;
 
     peers = rrp->peers;
     ngx_http_upstream_rr_peers_wlock(peers);
@@ -297,7 +297,7 @@ ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc, void *data)
 
         /* there are several peers */
 
-        peer = ngx_http_upstream_get_iwrr(oip);
+        peer = ngx_http_upstream_get_iwrr(uip);
 
         if (peer == NULL) {
             goto failed;
@@ -330,7 +330,7 @@ ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc, void *data)
 
         rrp->peers = peers->next;
 
-        oip->uiscf = oip->uiscf ? oip->uiscf->next : oip->uiscf;
+        uip->uiscf = uip->uiscf ? uip->uiscf->next : uip->uiscf;
 
         n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
                 / (8 * sizeof(uintptr_t));
@@ -341,7 +341,7 @@ ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc, void *data)
 
         ngx_http_upstream_rr_peers_unlock(peers);
 
-        rc = ngx_http_upstream_get_iwrr_peer(pc, oip);
+        rc = ngx_http_upstream_get_iwrr_peer(pc, uip);
 
         if (rc != NGX_BUSY) {
             return rc;
@@ -358,7 +358,7 @@ ngx_http_upstream_get_iwrr_peer(ngx_peer_connection_t *pc, void *data)
 }
 
 static ngx_http_upstream_rr_peer_t *
-ngx_http_upstream_get_iwrr(ngx_http_upstream_iwrr_peer_data_t *oip)
+ngx_http_upstream_get_iwrr(ngx_http_upstream_iwrr_peer_data_t *uip)
 {
     time_t                                 now;
     uintptr_t                              m;
@@ -371,9 +371,9 @@ ngx_http_upstream_get_iwrr(ngx_http_upstream_iwrr_peer_data_t *oip)
 
     now = ngx_time();
 
-    rrp = &oip->rrp;
+    rrp = &uip->rrp;
     peers = rrp->peers;
-    uiscf = oip->uiscf;
+    uiscf = uip->uiscf;
 
 #if (T_NGX_HTTP_UPSTREAM_RANDOM)
     if (uiscf->init_number == NGX_CONF_UNSET_UINT) {