nginx 0.5.8 *) Bugfix: a segmentation fault might occur if "client_body_in_file_only on" was used and a request body was small. *) Bugfix: a segmentation fault occurred if "client_body_in_file_only on" and "proxy_pass_request_body off" or "fastcgi_pass_request_body off" directives were used, and nginx switched to a next upstream. *) Bugfix: if the "proxy_buffering off" directive was used and a client connection was non-active, then the connection was closed after send timeout; bug appeared in 0.4.7. *) Bugfix: if the "epoll" method was used and a client closed a connection prematurely, then nginx closed the connection after a send timeout only. *) Bugfix: the "[alert] zero size buf" error when FastCGI server was used. *) Bugfixes in the "limit_zone" directive.

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>


void
ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin)
{

#if (NGX_HAVE_ATOMIC_OPS)

    ngx_uint_t  i, n;

    for ( ;; ) {

        if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
            return;
        }

        if (ngx_ncpu > 1) {

            for (n = 1; n < spin; n <<= 1) {

                for (i = 0; i < n; i++) {
                    ngx_cpu_pause();
                }

                if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
                    return;
                }
            }
        }

        ngx_sched_yield();
    }

#else

#if (NGX_THREADS)

#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !

#endif

#endif

}