Fixed lingering_time check. There are two significant changes in this patch: 1) The <= 0 comparison is done with a signed type. This fixes the case of ngx_time() being larger than r->lingering_time. 2) Calculation of r->lingering_time - ngx_time() is now always done in the ngx_msec_t type. This ensures the calculation is correct even if time_t is unsigned and differs in size from ngx_msec_t. Thanks to Lanshun Zhou.