--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -1827,19 +1827,13 @@ ngx_http_fastcgi_input_filter(ngx_event_
             break;
         }
 
-        if (p->free) {
-            cl = p->free;
-            b = cl->buf;
-            p->free = cl->next;
-            ngx_free_chain(p->pool, cl);
-
-        } else {
-            b = ngx_alloc_buf(p->pool);
-            if (b == NULL) {
-                return NGX_ERROR;
-            }
+        cl = ngx_chain_get_free_buf(p->pool, &p->free);
+        if (cl == NULL) {
+            return NGX_ERROR;
         }
 
+        b = cl->buf;
+
         ngx_memzero(b, sizeof(ngx_buf_t));
 
         b->pos = f->pos;
@@ -1852,14 +1846,6 @@ ngx_http_fastcgi_input_filter(ngx_event_
         *prev = b;
         prev = &b->shadow;
 
-        cl = ngx_alloc_chain_link(p->pool);
-        if (cl == NULL) {
-            return NGX_ERROR;
-        }
-
-        cl->buf = b;
-        cl->next = NULL;
-
         if (p->in) {
             *p->last_in = cl;
         } else {